/src/gdal/gcore/gdalthreadsafedataset.cpp
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1 | | /****************************************************************************** |
2 | | * |
3 | | * Project: GDAL Core |
4 | | * Purpose: Base class for thread safe dataset |
5 | | * Author: Even Rouault <even dot rouault at spatialys.com> |
6 | | * |
7 | | ****************************************************************************** |
8 | | * Copyright (c) 2024, Even Rouault <even dot rouault at spatialys.com> |
9 | | * |
10 | | * SPDX-License-Identifier: MIT |
11 | | ****************************************************************************/ |
12 | | |
13 | | #ifndef DOXYGEN_SKIP |
14 | | |
15 | | #include "cpl_mem_cache.h" |
16 | | #include "cpl_multiproc.h" |
17 | | #include "gdal_proxy.h" |
18 | | #include "gdal_rat.h" |
19 | | #include "gdal_priv.h" |
20 | | |
21 | | #include <map> |
22 | | #include <memory> |
23 | | #include <mutex> |
24 | | #include <thread> |
25 | | #include <vector> |
26 | | |
27 | | bool GDALThreadLocalDatasetCacheIsInDestruction(); |
28 | | |
29 | | /** Design notes of this file. |
30 | | * |
31 | | * This file is at the core of the "RFC 101 - Raster dataset read-only thread-safety". |
32 | | * Please consult it for high level understanding. |
33 | | * |
34 | | * 3 classes are involved: |
35 | | * - GDALThreadSafeDataset whose instances are returned to the user, and can |
36 | | * use them in a thread-safe way. |
37 | | * - GDALThreadSafeRasterBand whose instances are created (and owned) by a |
38 | | * GDALThreadSafeDataset instance, and returned to the user, which can use |
39 | | * them in a thread-safe way. |
40 | | * - GDALThreadLocalDatasetCache which is an internal class, which holds the |
41 | | * thread-local datasets. |
42 | | */ |
43 | | |
44 | | /************************************************************************/ |
45 | | /* GDALThreadLocalDatasetCache */ |
46 | | /************************************************************************/ |
47 | | |
48 | | class GDALThreadSafeDataset; |
49 | | |
50 | | /** This class is instantiated once per thread that uses a |
51 | | * GDALThreadSafeDataset instance. It holds mostly a cache that maps a |
52 | | * GDALThreadSafeDataset* pointer to the corresponding per-thread dataset. |
53 | | */ |
54 | | class GDALThreadLocalDatasetCache |
55 | | { |
56 | | private: |
57 | | /** Least-recently-used based cache that maps a GDALThreadSafeDataset* |
58 | | * instance to the corresponding per-thread dataset. |
59 | | * It should be noted as this a LRU cache, entries might get evicted when |
60 | | * its capacity is reached (64 datasets), which might be undesirable. |
61 | | * Hence it is doubled with m_oMapReferencedDS for datasets that are in |
62 | | * active used by a thread. |
63 | | * |
64 | | * This cache is created as a unique_ptr, and not a standard object, for |
65 | | * delicate reasons related to application termination, where we might |
66 | | * want to leak the memory associated to it, to avoid the dataset it |
67 | | * references from being closed, after GDAL has been "closed" (typically |
68 | | * GDALDestroyDriverManager() has been called), which would otherwise lead |
69 | | * to crashes. |
70 | | */ |
71 | | std::unique_ptr<lru11::Cache<const GDALThreadSafeDataset *, |
72 | | std::shared_ptr<GDALDataset>>> |
73 | | m_poCache{}; |
74 | | |
75 | | static thread_local bool tl_inDestruction; |
76 | | |
77 | | GDALThreadLocalDatasetCache(const GDALThreadLocalDatasetCache &) = delete; |
78 | | GDALThreadLocalDatasetCache & |
79 | | operator=(const GDALThreadLocalDatasetCache &) = delete; |
80 | | |
81 | | public: |
82 | | GDALThreadLocalDatasetCache(); |
83 | | ~GDALThreadLocalDatasetCache(); |
84 | | |
85 | | /** Thread-id of the thread that instantiated this object. Used only for |
86 | | * CPLDebug() purposes |
87 | | */ |
88 | | GIntBig m_nThreadID = 0; |
89 | | |
90 | | /** Mutex that protects access to m_oCache. There is "competition" around |
91 | | * access to m_oCache since the destructor of a GDALThreadSafeDataset |
92 | | * instance needs to evict entries corresponding to itself from all |
93 | | * GDALThreadLocalDatasetCache instances. |
94 | | */ |
95 | | std::mutex m_oMutex{}; |
96 | | |
97 | | /** This is a reference to *(m_poCache.get()). |
98 | | */ |
99 | | lru11::Cache<const GDALThreadSafeDataset *, std::shared_ptr<GDALDataset>> |
100 | | &m_oCache; |
101 | | |
102 | | /** Pair of shared_ptr<GDALDataset> with associated thread-local config |
103 | | * options that were valid in the calling thread at the time |
104 | | * GDALThreadLocalDatasetCache::RefUnderlyingDataset() was called, so they |
105 | | * can be restored at UnrefUnderlyingDataset() time. |
106 | | */ |
107 | | struct SharedPtrDatasetThreadLocalConfigOptionsPair |
108 | | { |
109 | | std::shared_ptr<GDALDataset> poDS; |
110 | | CPLStringList aosTLConfigOptions; |
111 | | |
112 | | SharedPtrDatasetThreadLocalConfigOptionsPair( |
113 | | const std::shared_ptr<GDALDataset> &poDSIn, |
114 | | CPLStringList &&aosTLConfigOptionsIn) |
115 | 0 | : poDS(poDSIn), aosTLConfigOptions(std::move(aosTLConfigOptionsIn)) |
116 | 0 | { |
117 | 0 | } |
118 | | }; |
119 | | |
120 | | /** Maps a GDALThreadSafeDataset* |
121 | | * instance to the corresponding per-thread dataset. Insertion into this |
122 | | * map is done by GDALThreadLocalDatasetCache::RefUnderlyingDataset() and |
123 | | * removal by UnrefUnderlyingDataset(). In most all use cases, the size of |
124 | | * this map should be 0 or 1 (not clear if it could be more, that would |
125 | | * involve RefUnderlyingDataset() being called in nested ways by the same |
126 | | * thread, but it doesn't hurt from being robust to that potential situation) |
127 | | */ |
128 | | std::map<const GDALThreadSafeDataset *, |
129 | | SharedPtrDatasetThreadLocalConfigOptionsPair> |
130 | | m_oMapReferencedDS{}; |
131 | | |
132 | | /** Maps a GDALRasterBand* returned by GDALThreadSafeRasterBand::RefUnderlyingDataset() |
133 | | * to the (thread-local) dataset that owns it (that is a dataset returned |
134 | | * by RefUnderlyingDataset(). The size of his map should be 0 or 1 in |
135 | | * most cases. |
136 | | */ |
137 | | std::map<GDALRasterBand *, GDALDataset *> m_oMapReferencedDSFromBand{}; |
138 | | |
139 | | static bool IsInDestruction() |
140 | 0 | { |
141 | 0 | return tl_inDestruction; |
142 | 0 | } |
143 | | }; |
144 | | |
145 | | /************************************************************************/ |
146 | | /* GDALThreadSafeDataset */ |
147 | | /************************************************************************/ |
148 | | |
149 | | /** Global variable used to determine if the singleton of GlobalCache |
150 | | * owned by GDALThreadSafeDataset is valid. |
151 | | * This is needed to avoid issues at process termination where the order |
152 | | * of destruction between static global instances and TLS instances can be |
153 | | * tricky. |
154 | | */ |
155 | | static bool bGlobalCacheValid = false; |
156 | | |
157 | | /** Thread-safe GDALDataset class. |
158 | | * |
159 | | * That class delegates all calls to its members to per-thread GDALDataset |
160 | | * instances. |
161 | | */ |
162 | | class GDALThreadSafeDataset final : public GDALProxyDataset |
163 | | { |
164 | | public: |
165 | | GDALThreadSafeDataset(std::unique_ptr<GDALDataset> poPrototypeDSUniquePtr, |
166 | | GDALDataset *poPrototypeDS); |
167 | | ~GDALThreadSafeDataset() override; |
168 | | |
169 | | CPLErr Close(GDALProgressFunc = nullptr, void * = nullptr) override; |
170 | | |
171 | | static std::unique_ptr<GDALDataset> |
172 | | Create(std::unique_ptr<GDALDataset> poPrototypeDS, int nScopeFlags); |
173 | | |
174 | | static GDALDataset *Create(GDALDataset *poPrototypeDS, int nScopeFlags); |
175 | | |
176 | | /* All below public methods override GDALDataset methods, and instead of |
177 | | * forwarding to a thread-local dataset, they act on the prototype dataset, |
178 | | * because they return a non-trivial type, that could be invalidated |
179 | | * otherwise if the thread-local dataset is evicted from the LRU cache. |
180 | | */ |
181 | | const OGRSpatialReference *GetSpatialRef() const override |
182 | 0 | { |
183 | 0 | std::lock_guard oGuard(m_oPrototypeDSMutex); |
184 | 0 | if (m_oSRS.IsEmpty()) |
185 | 0 | { |
186 | 0 | auto poSRS = m_poPrototypeDS->GetSpatialRef(); |
187 | 0 | if (poSRS) |
188 | 0 | { |
189 | 0 | m_oSRS.AssignAndSetThreadSafe(*poSRS); |
190 | 0 | } |
191 | 0 | } |
192 | 0 | return m_oSRS.IsEmpty() ? nullptr : &m_oSRS; |
193 | 0 | } |
194 | | |
195 | | const OGRSpatialReference *GetGCPSpatialRef() const override |
196 | 0 | { |
197 | 0 | std::lock_guard oGuard(m_oPrototypeDSMutex); |
198 | 0 | if (m_oGCPSRS.IsEmpty()) |
199 | 0 | { |
200 | 0 | auto poSRS = m_poPrototypeDS->GetGCPSpatialRef(); |
201 | 0 | if (poSRS) |
202 | 0 | { |
203 | 0 | m_oGCPSRS.AssignAndSetThreadSafe(*poSRS); |
204 | 0 | } |
205 | 0 | } |
206 | 0 | return m_oGCPSRS.IsEmpty() ? nullptr : &m_oGCPSRS; |
207 | 0 | } |
208 | | |
209 | | const GDAL_GCP *GetGCPs() override |
210 | 0 | { |
211 | 0 | std::lock_guard oGuard(m_oPrototypeDSMutex); |
212 | 0 | return const_cast<GDALDataset *>(m_poPrototypeDS)->GetGCPs(); |
213 | 0 | } |
214 | | |
215 | | const char *GetMetadataItem(const char *pszName, |
216 | | const char *pszDomain = "") override |
217 | 0 | { |
218 | 0 | std::lock_guard oGuard(m_oPrototypeDSMutex); |
219 | 0 | return const_cast<GDALDataset *>(m_poPrototypeDS) |
220 | 0 | ->GetMetadataItem(pszName, pszDomain); |
221 | 0 | } |
222 | | |
223 | | char **GetMetadata(const char *pszDomain = "") override |
224 | 0 | { |
225 | 0 | std::lock_guard oGuard(m_oPrototypeDSMutex); |
226 | 0 | return const_cast<GDALDataset *>(m_poPrototypeDS) |
227 | 0 | ->GetMetadata(pszDomain); |
228 | 0 | } |
229 | | |
230 | | /* End of methods that forward on the prototype dataset */ |
231 | | |
232 | | GDALAsyncReader *BeginAsyncReader(int, int, int, int, void *, int, int, |
233 | | GDALDataType, int, int *, int, int, int, |
234 | | char **) override |
235 | 0 | { |
236 | 0 | CPLError(CE_Failure, CPLE_AppDefined, |
237 | 0 | "GDALThreadSafeDataset::BeginAsyncReader() not supported"); |
238 | 0 | return nullptr; |
239 | 0 | } |
240 | | |
241 | | protected: |
242 | | GDALDataset *RefUnderlyingDataset() const override; |
243 | | |
244 | | void |
245 | | UnrefUnderlyingDataset(GDALDataset *poUnderlyingDataset) const override; |
246 | | |
247 | | int CloseDependentDatasets() override; |
248 | | |
249 | | private: |
250 | | friend class GDALThreadSafeRasterBand; |
251 | | friend class GDALThreadLocalDatasetCache; |
252 | | |
253 | | /** Mutex that protects accesses to m_poPrototypeDS */ |
254 | | mutable std::mutex m_oPrototypeDSMutex{}; |
255 | | |
256 | | /** "Prototype" dataset, that is the dataset that was passed to the |
257 | | * GDALThreadSafeDataset constructor. All calls on to it should be on |
258 | | * const methods, and should be protected by m_oPrototypeDSMutex (except |
259 | | * during GDALThreadSafeDataset instance construction) |
260 | | */ |
261 | | const GDALDataset *m_poPrototypeDS = nullptr; |
262 | | |
263 | | /** Unique pointer for m_poPrototypeDS in the cases where GDALThreadSafeDataset |
264 | | * has been passed a unique pointer */ |
265 | | std::unique_ptr<GDALDataset> m_poPrototypeDSUniquePtr{}; |
266 | | |
267 | | /** Thread-local config options at the time where GDALThreadSafeDataset |
268 | | * has been constructed. |
269 | | */ |
270 | | const CPLStringList m_aosThreadLocalConfigOptions{}; |
271 | | |
272 | | /** Cached value returned by GetSpatialRef() */ |
273 | | mutable OGRSpatialReference m_oSRS{}; |
274 | | |
275 | | /** Cached value returned by GetGCPSpatialRef() */ |
276 | | mutable OGRSpatialReference m_oGCPSRS{}; |
277 | | |
278 | | /** Structure that references all GDALThreadLocalDatasetCache* instances. |
279 | | */ |
280 | | struct GlobalCache |
281 | | { |
282 | | /** Mutex that protect access to oSetOfCache */ |
283 | | std::mutex oMutex{}; |
284 | | |
285 | | /** Set of GDALThreadLocalDatasetCache* instances. That is it has |
286 | | * one entry per thread that has used at least once a |
287 | | * GDALThreadLocalDatasetCache/GDALThreadSafeRasterBand |
288 | | */ |
289 | | std::set<GDALThreadLocalDatasetCache *> oSetOfCache{}; |
290 | | |
291 | | GlobalCache() |
292 | 0 | { |
293 | 0 | bGlobalCacheValid = true; |
294 | 0 | } |
295 | | |
296 | | ~GlobalCache() |
297 | 0 | { |
298 | 0 | bGlobalCacheValid = false; |
299 | 0 | } |
300 | | }; |
301 | | |
302 | | /** Returns a singleton for a GlobalCache instance that references all |
303 | | * GDALThreadLocalDatasetCache* instances. |
304 | | */ |
305 | | static GlobalCache &GetSetOfCache() |
306 | 0 | { |
307 | 0 | static GlobalCache cache; |
308 | 0 | return cache; |
309 | 0 | } |
310 | | |
311 | | /** Thread-local dataset cache. */ |
312 | | static thread_local std::unique_ptr<GDALThreadLocalDatasetCache> tl_poCache; |
313 | | |
314 | | void UnrefUnderlyingDataset(GDALDataset *poUnderlyingDataset, |
315 | | GDALThreadLocalDatasetCache *poCache) const; |
316 | | |
317 | | GDALThreadSafeDataset(const GDALThreadSafeDataset &) = delete; |
318 | | GDALThreadSafeDataset &operator=(const GDALThreadSafeDataset &) = delete; |
319 | | }; |
320 | | |
321 | | /************************************************************************/ |
322 | | /* GDALThreadSafeRasterBand */ |
323 | | /************************************************************************/ |
324 | | |
325 | | /** Thread-safe GDALRasterBand class. |
326 | | * |
327 | | * That class delegates all calls to its members to per-thread GDALDataset |
328 | | * instances. |
329 | | */ |
330 | | class GDALThreadSafeRasterBand final : public GDALProxyRasterBand |
331 | | { |
332 | | public: |
333 | | GDALThreadSafeRasterBand(GDALThreadSafeDataset *poTSDS, |
334 | | GDALDataset *poParentDS, int nBandIn, |
335 | | GDALRasterBand *poPrototypeBand, |
336 | | int nBaseBandOfMaskBand, int nOvrIdx); |
337 | | |
338 | | GDALRasterBand *GetMaskBand() override; |
339 | | int GetOverviewCount() override; |
340 | | GDALRasterBand *GetOverview(int idx) override; |
341 | | GDALRasterBand *GetRasterSampleOverview(GUIntBig nDesiredSamples) override; |
342 | | |
343 | | GDALRasterAttributeTable *GetDefaultRAT() override; |
344 | | |
345 | | /* All below public methods override GDALRasterBand methods, and instead of |
346 | | * forwarding to a thread-local dataset, they act on the prototype band, |
347 | | * because they return a non-trivial type, that could be invalidated |
348 | | * otherwise if the thread-local dataset is evicted from the LRU cache. |
349 | | */ |
350 | | const char *GetMetadataItem(const char *pszName, |
351 | | const char *pszDomain = "") override |
352 | 0 | { |
353 | 0 | std::lock_guard oGuard(m_poTSDS->m_oPrototypeDSMutex); |
354 | 0 | return const_cast<GDALRasterBand *>(m_poPrototypeBand) |
355 | 0 | ->GetMetadataItem(pszName, pszDomain); |
356 | 0 | } |
357 | | |
358 | | char **GetMetadata(const char *pszDomain = "") override |
359 | 0 | { |
360 | 0 | std::lock_guard oGuard(m_poTSDS->m_oPrototypeDSMutex); |
361 | 0 | return const_cast<GDALRasterBand *>(m_poPrototypeBand) |
362 | 0 | ->GetMetadata(pszDomain); |
363 | 0 | } |
364 | | |
365 | | const char *GetUnitType() override |
366 | 0 | { |
367 | 0 | std::lock_guard oGuard(m_poTSDS->m_oPrototypeDSMutex); |
368 | 0 | return const_cast<GDALRasterBand *>(m_poPrototypeBand)->GetUnitType(); |
369 | 0 | } |
370 | | |
371 | | GDALColorTable *GetColorTable() override |
372 | 0 | { |
373 | 0 | std::lock_guard oGuard(m_poTSDS->m_oPrototypeDSMutex); |
374 | 0 | return const_cast<GDALRasterBand *>(m_poPrototypeBand)->GetColorTable(); |
375 | 0 | } |
376 | | |
377 | | /* End of methods that forward on the prototype band */ |
378 | | |
379 | | CPLVirtualMem *GetVirtualMemAuto(GDALRWFlag, int *, GIntBig *, |
380 | | char **) override |
381 | 0 | { |
382 | 0 | CPLError(CE_Failure, CPLE_AppDefined, |
383 | 0 | "GDALThreadSafeRasterBand::GetVirtualMemAuto() not supported"); |
384 | 0 | return nullptr; |
385 | 0 | } |
386 | | |
387 | | protected: |
388 | | GDALRasterBand *RefUnderlyingRasterBand(bool bForceOpen) const override; |
389 | | void UnrefUnderlyingRasterBand( |
390 | | GDALRasterBand *poUnderlyingRasterBand) const override; |
391 | | |
392 | | private: |
393 | | /** Pointer to the thread-safe dataset from which this band has been |
394 | | *created */ |
395 | | GDALThreadSafeDataset *m_poTSDS = nullptr; |
396 | | |
397 | | /** Pointer to the "prototype" raster band that corresponds to us. |
398 | | * All calls to m_poPrototypeBand should be protected by |
399 | | * GDALThreadSafeDataset:m_oPrototypeDSMutex. |
400 | | */ |
401 | | const GDALRasterBand *m_poPrototypeBand = nullptr; |
402 | | |
403 | | /** 0 for standard bands, otherwise > 0 value that indicates that this |
404 | | * band is a mask band and m_nBaseBandOfMaskBand is then the number |
405 | | * of the band that is the parent of the mask band. |
406 | | */ |
407 | | const int m_nBaseBandOfMaskBand; |
408 | | |
409 | | /** 0 for standard bands, otherwise >= 0 value that indicates that this |
410 | | * band is an overview band and m_nOvrIdx is then the index of the overview. |
411 | | */ |
412 | | const int m_nOvrIdx; |
413 | | |
414 | | /** Mask band associated with this band. */ |
415 | | std::unique_ptr<GDALRasterBand> m_poMaskBand{}; |
416 | | |
417 | | /** List of overviews associated with this band. */ |
418 | | std::vector<std::unique_ptr<GDALRasterBand>> m_apoOverviews{}; |
419 | | |
420 | | GDALThreadSafeRasterBand(const GDALThreadSafeRasterBand &) = delete; |
421 | | GDALThreadSafeRasterBand & |
422 | | operator=(const GDALThreadSafeRasterBand &) = delete; |
423 | | }; |
424 | | |
425 | | /************************************************************************/ |
426 | | /* Global variables initialization. */ |
427 | | /************************************************************************/ |
428 | | |
429 | | /** Instantiation of the TLS cache of datasets */ |
430 | | thread_local std::unique_ptr<GDALThreadLocalDatasetCache> |
431 | | GDALThreadSafeDataset::tl_poCache; |
432 | | |
433 | | thread_local bool GDALThreadLocalDatasetCache::tl_inDestruction = false; |
434 | | |
435 | | /************************************************************************/ |
436 | | /* GDALThreadLocalDatasetCache() */ |
437 | | /************************************************************************/ |
438 | | |
439 | | /** Constructor of GDALThreadLocalDatasetCache. This is called implicitly |
440 | | * when GDALThreadSafeDataset::tl_poCache is called the first time by a |
441 | | * thread. |
442 | | */ |
443 | | GDALThreadLocalDatasetCache::GDALThreadLocalDatasetCache() |
444 | 0 | : m_poCache(std::make_unique<lru11::Cache<const GDALThreadSafeDataset *, |
445 | 0 | std::shared_ptr<GDALDataset>>>()), |
446 | 0 | m_nThreadID(CPLGetPID()), m_oCache(*m_poCache.get()) |
447 | 0 | { |
448 | 0 | CPLDebug("GDAL", |
449 | 0 | "Registering thread-safe dataset cache for thread " CPL_FRMT_GIB, |
450 | 0 | m_nThreadID); |
451 | | |
452 | | // We reference ourselves to the GDALThreadSafeDataset set-of-cache singleton |
453 | 0 | auto &oSetOfCache = GDALThreadSafeDataset::GetSetOfCache(); |
454 | 0 | std::lock_guard oLock(oSetOfCache.oMutex); |
455 | 0 | oSetOfCache.oSetOfCache.insert(this); |
456 | 0 | } |
457 | | |
458 | | /************************************************************************/ |
459 | | /* ~GDALThreadLocalDatasetCache() */ |
460 | | /************************************************************************/ |
461 | | |
462 | | /** Destructor of GDALThreadLocalDatasetCache. This is called implicitly when a |
463 | | * thread is terminated. |
464 | | */ |
465 | | GDALThreadLocalDatasetCache::~GDALThreadLocalDatasetCache() |
466 | 0 | { |
467 | 0 | tl_inDestruction = true; |
468 | | |
469 | | // If GDAL has been de-initialized explicitly (ie GDALDestroyDriverManager() |
470 | | // has been called), or we are during process termination, do not try to |
471 | | // free m_poCache at all, which would cause the datasets its owned to be |
472 | | // destroyed, which will generally lead to crashes in those situations where |
473 | | // GDAL has been de-initialized. |
474 | 0 | const bool bDriverManagerDestroyed = *GDALGetphDMMutex() == nullptr; |
475 | 0 | if (bDriverManagerDestroyed || !bGlobalCacheValid) |
476 | 0 | { |
477 | 0 | #ifndef __COVERITY__ |
478 | | // Leak datasets when GDAL has been de-initialized |
479 | 0 | if (!m_poCache->empty()) |
480 | 0 | { |
481 | 0 | CPL_IGNORE_RET_VAL(m_poCache.release()); |
482 | 0 | } |
483 | 0 | #endif |
484 | 0 | return; |
485 | 0 | } |
486 | | |
487 | | // Unreference ourselves from the GDALThreadSafeDataset set-of-cache singleton |
488 | 0 | CPLDebug("GDAL", |
489 | 0 | "Unregistering thread-safe dataset cache for thread " CPL_FRMT_GIB, |
490 | 0 | m_nThreadID); |
491 | 0 | { |
492 | 0 | auto &oSetOfCache = GDALThreadSafeDataset::GetSetOfCache(); |
493 | 0 | std::lock_guard oLock(oSetOfCache.oMutex); |
494 | 0 | oSetOfCache.oSetOfCache.erase(this); |
495 | 0 | } |
496 | | |
497 | | // Below code is just for debugging purposes and show which internal |
498 | | // thread-local datasets are released at thread termination. |
499 | 0 | const auto lambda = |
500 | 0 | [this](const lru11::KeyValuePair<const GDALThreadSafeDataset *, |
501 | 0 | std::shared_ptr<GDALDataset>> &kv) |
502 | 0 | { |
503 | 0 | CPLDebug("GDAL", |
504 | 0 | "~GDALThreadLocalDatasetCache(): GDALClose(%s, this=%p) " |
505 | 0 | "for thread " CPL_FRMT_GIB, |
506 | 0 | kv.value->GetDescription(), kv.value.get(), m_nThreadID); |
507 | 0 | }; |
508 | 0 | m_oCache.cwalk(lambda); |
509 | 0 | } |
510 | | |
511 | | /************************************************************************/ |
512 | | /* GDALThreadLocalDatasetCacheIsInDestruction() */ |
513 | | /************************************************************************/ |
514 | | |
515 | | bool GDALThreadLocalDatasetCacheIsInDestruction() |
516 | 0 | { |
517 | 0 | return GDALThreadLocalDatasetCache::IsInDestruction(); |
518 | 0 | } |
519 | | |
520 | | /************************************************************************/ |
521 | | /* GDALThreadSafeDataset() */ |
522 | | /************************************************************************/ |
523 | | |
524 | | /** Constructor of GDALThreadSafeDataset. |
525 | | * It may be called with poPrototypeDSUniquePtr set to null, in the situations |
526 | | * where GDALThreadSafeDataset doesn't own the prototype dataset. |
527 | | * poPrototypeDS should always be not-null, and if poPrototypeDSUniquePtr is |
528 | | * not null, then poPrototypeDS should be equal to poPrototypeDSUniquePtr.get() |
529 | | */ |
530 | | GDALThreadSafeDataset::GDALThreadSafeDataset( |
531 | | std::unique_ptr<GDALDataset> poPrototypeDSUniquePtr, |
532 | | GDALDataset *poPrototypeDS) |
533 | 0 | : m_poPrototypeDS(poPrototypeDS), |
534 | 0 | m_aosThreadLocalConfigOptions(CPLGetThreadLocalConfigOptions()) |
535 | 0 | { |
536 | 0 | CPLAssert(poPrototypeDS != nullptr); |
537 | 0 | if (poPrototypeDSUniquePtr) |
538 | 0 | { |
539 | 0 | CPLAssert(poPrototypeDS == poPrototypeDSUniquePtr.get()); |
540 | 0 | } |
541 | | |
542 | | // Replicate the characteristics of the prototype dataset onto ourselves |
543 | 0 | nRasterXSize = poPrototypeDS->GetRasterXSize(); |
544 | 0 | nRasterYSize = poPrototypeDS->GetRasterYSize(); |
545 | 0 | for (int i = 1; i <= poPrototypeDS->GetRasterCount(); ++i) |
546 | 0 | { |
547 | 0 | SetBand(i, std::make_unique<GDALThreadSafeRasterBand>( |
548 | 0 | this, this, i, poPrototypeDS->GetRasterBand(i), 0, -1)); |
549 | 0 | } |
550 | 0 | nOpenFlags = GDAL_OF_RASTER | GDAL_OF_THREAD_SAFE; |
551 | 0 | SetDescription(poPrototypeDS->GetDescription()); |
552 | 0 | papszOpenOptions = CSLDuplicate(poPrototypeDS->GetOpenOptions()); |
553 | |
|
554 | 0 | m_poPrototypeDSUniquePtr = std::move(poPrototypeDSUniquePtr); |
555 | | |
556 | | // In the case where we are constructed without owning the prototype |
557 | | // dataset, let's increase its reference counter though. |
558 | 0 | if (!m_poPrototypeDSUniquePtr) |
559 | 0 | const_cast<GDALDataset *>(m_poPrototypeDS)->Reference(); |
560 | 0 | } |
561 | | |
562 | | /************************************************************************/ |
563 | | /* Create() */ |
564 | | /************************************************************************/ |
565 | | |
566 | | /** Utility method used by GDALGetThreadSafeDataset() to construct a |
567 | | * GDALThreadSafeDataset instance in the case where the GDALThreadSafeDataset |
568 | | * instance owns the prototype dataset. |
569 | | */ |
570 | | |
571 | | /* static */ std::unique_ptr<GDALDataset> |
572 | | GDALThreadSafeDataset::Create(std::unique_ptr<GDALDataset> poPrototypeDS, |
573 | | int nScopeFlags) |
574 | 0 | { |
575 | 0 | if (nScopeFlags != GDAL_OF_RASTER) |
576 | 0 | { |
577 | 0 | CPLError(CE_Failure, CPLE_NotSupported, |
578 | 0 | "GDALGetThreadSafeDataset(): Only nScopeFlags == " |
579 | 0 | "GDAL_OF_RASTER is supported"); |
580 | 0 | return nullptr; |
581 | 0 | } |
582 | 0 | if (poPrototypeDS->IsThreadSafe(nScopeFlags)) |
583 | 0 | { |
584 | 0 | return poPrototypeDS; |
585 | 0 | } |
586 | 0 | if (!poPrototypeDS->CanBeCloned(nScopeFlags, /* bCanShareState = */ true)) |
587 | 0 | { |
588 | 0 | CPLError(CE_Failure, CPLE_NotSupported, |
589 | 0 | "GDALGetThreadSafeDataset(): Source dataset cannot be " |
590 | 0 | "cloned"); |
591 | 0 | return nullptr; |
592 | 0 | } |
593 | 0 | auto poPrototypeDSRaw = poPrototypeDS.get(); |
594 | 0 | return std::make_unique<GDALThreadSafeDataset>(std::move(poPrototypeDS), |
595 | 0 | poPrototypeDSRaw); |
596 | 0 | } |
597 | | |
598 | | /************************************************************************/ |
599 | | /* Create() */ |
600 | | /************************************************************************/ |
601 | | |
602 | | /** Utility method used by GDALGetThreadSafeDataset() to construct a |
603 | | * GDALThreadSafeDataset instance in the case where the GDALThreadSafeDataset |
604 | | * instance does not own the prototype dataset. |
605 | | */ |
606 | | |
607 | | /* static */ GDALDataset * |
608 | | GDALThreadSafeDataset::Create(GDALDataset *poPrototypeDS, int nScopeFlags) |
609 | 0 | { |
610 | 0 | if (nScopeFlags != GDAL_OF_RASTER) |
611 | 0 | { |
612 | 0 | CPLError(CE_Failure, CPLE_NotSupported, |
613 | 0 | "GDALGetThreadSafeDataset(): Only nScopeFlags == " |
614 | 0 | "GDAL_OF_RASTER is supported"); |
615 | 0 | return nullptr; |
616 | 0 | } |
617 | 0 | if (poPrototypeDS->IsThreadSafe(nScopeFlags)) |
618 | 0 | { |
619 | 0 | poPrototypeDS->Reference(); |
620 | 0 | return poPrototypeDS; |
621 | 0 | } |
622 | 0 | if (!poPrototypeDS->CanBeCloned(nScopeFlags, /* bCanShareState = */ true)) |
623 | 0 | { |
624 | 0 | CPLError(CE_Failure, CPLE_NotSupported, |
625 | 0 | "GDALGetThreadSafeDataset(): Source dataset cannot be " |
626 | 0 | "cloned"); |
627 | 0 | return nullptr; |
628 | 0 | } |
629 | 0 | return std::make_unique<GDALThreadSafeDataset>(nullptr, poPrototypeDS) |
630 | 0 | .release(); |
631 | 0 | } |
632 | | |
633 | | /************************************************************************/ |
634 | | /* ~GDALThreadSafeDataset() */ |
635 | | /************************************************************************/ |
636 | | |
637 | | GDALThreadSafeDataset::~GDALThreadSafeDataset() |
638 | 0 | { |
639 | 0 | GDALThreadSafeDataset::Close(); |
640 | 0 | } |
641 | | |
642 | | /************************************************************************/ |
643 | | /* Close() */ |
644 | | /************************************************************************/ |
645 | | |
646 | | CPLErr GDALThreadSafeDataset::Close(GDALProgressFunc, void *) |
647 | 0 | { |
648 | 0 | CPLErr eErr = CE_None; |
649 | 0 | if (nOpenFlags != OPEN_FLAGS_CLOSED) |
650 | 0 | { |
651 | | // Collect TLS datasets in a vector, and free them after releasing |
652 | | // g_nInDestructorCounter to limit contention |
653 | 0 | std::vector<std::pair<std::shared_ptr<GDALDataset>, GIntBig>> |
654 | 0 | aoDSToFree; |
655 | 0 | { |
656 | 0 | auto &oSetOfCache = GetSetOfCache(); |
657 | 0 | std::lock_guard oLock(oSetOfCache.oMutex); |
658 | 0 | for (auto *poCache : oSetOfCache.oSetOfCache) |
659 | 0 | { |
660 | 0 | std::unique_lock oLockCache(poCache->m_oMutex); |
661 | 0 | std::shared_ptr<GDALDataset> poDS; |
662 | 0 | if (poCache->m_oCache.tryGet(this, poDS)) |
663 | 0 | { |
664 | 0 | aoDSToFree.emplace_back(std::move(poDS), |
665 | 0 | poCache->m_nThreadID); |
666 | 0 | poCache->m_oCache.remove(this); |
667 | 0 | } |
668 | 0 | } |
669 | 0 | } |
670 | |
|
671 | 0 | for (const auto &oEntry : aoDSToFree) |
672 | 0 | { |
673 | 0 | CPLDebug("GDAL", |
674 | 0 | "~GDALThreadSafeDataset(): GDALClose(%s, this=%p) for " |
675 | 0 | "thread " CPL_FRMT_GIB, |
676 | 0 | GetDescription(), oEntry.first.get(), oEntry.second); |
677 | 0 | } |
678 | | // Actually release TLS datasets |
679 | 0 | aoDSToFree.clear(); |
680 | |
|
681 | 0 | GDALThreadSafeDataset::CloseDependentDatasets(); |
682 | |
|
683 | 0 | eErr = GDALDataset::Close(); |
684 | 0 | } |
685 | |
|
686 | 0 | return eErr; |
687 | 0 | } |
688 | | |
689 | | /************************************************************************/ |
690 | | /* CloseDependentDatasets() */ |
691 | | /************************************************************************/ |
692 | | |
693 | | /** Implements GDALDataset::CloseDependentDatasets() |
694 | | * |
695 | | * Takes care of releasing the prototype dataset. |
696 | | * |
697 | | * As implied by the contract of CloseDependentDatasets(), returns true if |
698 | | * the prototype dataset has actually been released (or false if |
699 | | * CloseDependentDatasets() has already been closed) |
700 | | */ |
701 | | int GDALThreadSafeDataset::CloseDependentDatasets() |
702 | 0 | { |
703 | 0 | int bRet = false; |
704 | 0 | if (m_poPrototypeDSUniquePtr) |
705 | 0 | { |
706 | 0 | bRet = true; |
707 | 0 | } |
708 | 0 | else if (m_poPrototypeDS) |
709 | 0 | { |
710 | 0 | if (const_cast<GDALDataset *>(m_poPrototypeDS)->ReleaseRef()) |
711 | 0 | { |
712 | 0 | bRet = true; |
713 | 0 | } |
714 | 0 | } |
715 | |
|
716 | 0 | m_poPrototypeDSUniquePtr.reset(); |
717 | 0 | m_poPrototypeDS = nullptr; |
718 | |
|
719 | 0 | return bRet; |
720 | 0 | } |
721 | | |
722 | | /************************************************************************/ |
723 | | /* RefUnderlyingDataset() */ |
724 | | /************************************************************************/ |
725 | | |
726 | | /** Implements GDALProxyDataset::RefUnderlyingDataset. |
727 | | * |
728 | | * This method is called by all virtual methods of GDALDataset overridden by |
729 | | * RefUnderlyingDataset() when it delegates the calls to the underlying |
730 | | * dataset. |
731 | | * |
732 | | * Our implementation takes care of opening a thread-local dataset, on the |
733 | | * same underlying dataset of m_poPrototypeDS, if needed, and to insert it |
734 | | * into a cache for fast later uses by the same thread. |
735 | | */ |
736 | | GDALDataset *GDALThreadSafeDataset::RefUnderlyingDataset() const |
737 | 0 | { |
738 | | // Back-up thread-local config options at the time we are called |
739 | 0 | CPLStringList aosTLConfigOptionsBackup(CPLGetThreadLocalConfigOptions()); |
740 | | |
741 | | // Now merge the thread-local config options at the time where this |
742 | | // instance has been created with the current ones. |
743 | 0 | const CPLStringList aosMerged( |
744 | 0 | CSLMerge(CSLDuplicate(m_aosThreadLocalConfigOptions.List()), |
745 | 0 | aosTLConfigOptionsBackup.List())); |
746 | | |
747 | | // And make that merged list active |
748 | 0 | CPLSetThreadLocalConfigOptions(aosMerged.List()); |
749 | |
|
750 | 0 | std::shared_ptr<GDALDataset> poTLSDS; |
751 | | |
752 | | // Get the thread-local dataset cache for this thread. |
753 | 0 | GDALThreadLocalDatasetCache *poCache = tl_poCache.get(); |
754 | 0 | if (!poCache) |
755 | 0 | { |
756 | 0 | auto poCacheUniquePtr = std::make_unique<GDALThreadLocalDatasetCache>(); |
757 | 0 | poCache = poCacheUniquePtr.get(); |
758 | 0 | tl_poCache = std::move(poCacheUniquePtr); |
759 | 0 | } |
760 | | |
761 | | // Check if there's an entry in this cache for our current GDALThreadSafeDataset |
762 | | // instance. |
763 | 0 | std::unique_lock oLock(poCache->m_oMutex); |
764 | 0 | if (poCache->m_oCache.tryGet(this, poTLSDS)) |
765 | 0 | { |
766 | | // If so, return it, but before returning, make sure to creates a |
767 | | // "hard" reference to the thread-local dataset, in case it would |
768 | | // get evicted from poCache->m_oCache (by other threads that would |
769 | | // access lots of datasets in between) |
770 | 0 | CPLAssert(!cpl::contains(poCache->m_oMapReferencedDS, this)); |
771 | 0 | auto poDSRet = poTLSDS.get(); |
772 | 0 | poCache->m_oMapReferencedDS.insert( |
773 | 0 | {this, GDALThreadLocalDatasetCache:: |
774 | 0 | SharedPtrDatasetThreadLocalConfigOptionsPair( |
775 | 0 | poTLSDS, std::move(aosTLConfigOptionsBackup))}); |
776 | 0 | return poDSRet; |
777 | 0 | } |
778 | | |
779 | | // "Clone" the prototype dataset, which in 99% of the cases, involves |
780 | | // doing a GDALDataset::Open() call to re-open it. Do that by temporarily |
781 | | // dropping the lock that protects poCache->m_oCache. |
782 | 0 | oLock.unlock(); |
783 | 0 | poTLSDS = m_poPrototypeDS->Clone(GDAL_OF_RASTER, /* bCanShareState=*/true); |
784 | 0 | if (poTLSDS) |
785 | 0 | { |
786 | 0 | CPLDebug("GDAL", "GDALOpen(%s, this=%p) for thread " CPL_FRMT_GIB, |
787 | 0 | GetDescription(), poTLSDS.get(), CPLGetPID()); |
788 | | |
789 | | // Check that the re-openeded dataset has the same characteristics |
790 | | // as "this" / m_poPrototypeDS |
791 | 0 | if (poTLSDS->GetRasterXSize() != nRasterXSize || |
792 | 0 | poTLSDS->GetRasterYSize() != nRasterYSize || |
793 | 0 | poTLSDS->GetRasterCount() != nBands) |
794 | 0 | { |
795 | 0 | poTLSDS.reset(); |
796 | 0 | CPLError(CE_Failure, CPLE_AppDefined, |
797 | 0 | "Re-opened dataset for %s does not share the same " |
798 | 0 | "characteristics as the master dataset", |
799 | 0 | GetDescription()); |
800 | 0 | } |
801 | 0 | } |
802 | | |
803 | | // Re-acquire the lok |
804 | 0 | oLock.lock(); |
805 | | |
806 | | // In case of failed closing, restore the thread-local config options that |
807 | | // were valid at the beginning of this method, and return in error. |
808 | 0 | if (!poTLSDS) |
809 | 0 | { |
810 | 0 | CPLSetThreadLocalConfigOptions(aosTLConfigOptionsBackup.List()); |
811 | 0 | return nullptr; |
812 | 0 | } |
813 | | |
814 | | // We have managed to get a thread-local dataset. Insert it into the |
815 | | // LRU cache and the m_oMapReferencedDS map that holds strong references. |
816 | 0 | auto poDSRet = poTLSDS.get(); |
817 | 0 | { |
818 | 0 | poCache->m_oCache.insert(this, poTLSDS); |
819 | 0 | CPLAssert(!cpl::contains(poCache->m_oMapReferencedDS, this)); |
820 | 0 | poCache->m_oMapReferencedDS.insert( |
821 | 0 | {this, GDALThreadLocalDatasetCache:: |
822 | 0 | SharedPtrDatasetThreadLocalConfigOptionsPair( |
823 | 0 | poTLSDS, std::move(aosTLConfigOptionsBackup))}); |
824 | 0 | } |
825 | 0 | return poDSRet; |
826 | 0 | } |
827 | | |
828 | | /************************************************************************/ |
829 | | /* UnrefUnderlyingDataset() */ |
830 | | /************************************************************************/ |
831 | | |
832 | | /** Implements GDALProxyDataset::UnrefUnderlyingDataset. |
833 | | * |
834 | | * This is called by GDALProxyDataset overridden methods of GDALDataset, when |
835 | | * they no longer need to access the underlying dataset. |
836 | | * |
837 | | * This method actually delegates most of the work to the other |
838 | | * UnrefUnderlyingDataset() method that takes an explicit GDALThreadLocalDatasetCache* |
839 | | * instance. |
840 | | */ |
841 | | void GDALThreadSafeDataset::UnrefUnderlyingDataset( |
842 | | GDALDataset *poUnderlyingDataset) const |
843 | 0 | { |
844 | 0 | GDALThreadLocalDatasetCache *poCache = tl_poCache.get(); |
845 | 0 | CPLAssert(poCache); |
846 | 0 | std::unique_lock oLock(poCache->m_oMutex); |
847 | 0 | UnrefUnderlyingDataset(poUnderlyingDataset, poCache); |
848 | 0 | } |
849 | | |
850 | | /************************************************************************/ |
851 | | /* UnrefUnderlyingDataset() */ |
852 | | /************************************************************************/ |
853 | | |
854 | | /** Takes care of removing the strong reference to a thread-local dataset |
855 | | * from the TLS cache of datasets. |
856 | | */ |
857 | | void GDALThreadSafeDataset::UnrefUnderlyingDataset( |
858 | | [[maybe_unused]] GDALDataset *poUnderlyingDataset, |
859 | | GDALThreadLocalDatasetCache *poCache) const |
860 | 0 | { |
861 | 0 | auto oIter = poCache->m_oMapReferencedDS.find(this); |
862 | 0 | CPLAssert(oIter != poCache->m_oMapReferencedDS.end()); |
863 | 0 | CPLAssert(oIter->second.poDS.get() == poUnderlyingDataset); |
864 | 0 | CPLSetThreadLocalConfigOptions(oIter->second.aosTLConfigOptions.List()); |
865 | 0 | poCache->m_oMapReferencedDS.erase(oIter); |
866 | 0 | } |
867 | | |
868 | | /************************************************************************/ |
869 | | /* GDALThreadSafeRasterBand() */ |
870 | | /************************************************************************/ |
871 | | |
872 | | GDALThreadSafeRasterBand::GDALThreadSafeRasterBand( |
873 | | GDALThreadSafeDataset *poTSDS, GDALDataset *poParentDS, int nBandIn, |
874 | | GDALRasterBand *poPrototypeBand, int nBaseBandOfMaskBand, int nOvrIdx) |
875 | 0 | : m_poTSDS(poTSDS), m_poPrototypeBand(poPrototypeBand), |
876 | 0 | m_nBaseBandOfMaskBand(nBaseBandOfMaskBand), m_nOvrIdx(nOvrIdx) |
877 | 0 | { |
878 | | // Replicates characteristics of the prototype band. |
879 | 0 | poDS = poParentDS; |
880 | 0 | nBand = nBandIn; |
881 | 0 | eDataType = poPrototypeBand->GetRasterDataType(); |
882 | 0 | nRasterXSize = poPrototypeBand->GetXSize(); |
883 | 0 | nRasterYSize = poPrototypeBand->GetYSize(); |
884 | 0 | poPrototypeBand->GetBlockSize(&nBlockXSize, &nBlockYSize); |
885 | |
|
886 | 0 | if (nBandIn > 0) |
887 | 0 | { |
888 | | // For regular bands instantiates a (thread-safe) mask band and |
889 | | // as many overviews as needed. |
890 | |
|
891 | 0 | m_poMaskBand = std::make_unique<GDALThreadSafeRasterBand>( |
892 | 0 | poTSDS, nullptr, 0, poPrototypeBand->GetMaskBand(), nBandIn, |
893 | 0 | nOvrIdx); |
894 | 0 | if (nOvrIdx < 0) |
895 | 0 | { |
896 | 0 | const int nOvrCount = poPrototypeBand->GetOverviewCount(); |
897 | 0 | for (int iOvrIdx = 0; iOvrIdx < nOvrCount; ++iOvrIdx) |
898 | 0 | { |
899 | 0 | m_apoOverviews.emplace_back( |
900 | 0 | std::make_unique<GDALThreadSafeRasterBand>( |
901 | 0 | poTSDS, nullptr, nBandIn, |
902 | 0 | poPrototypeBand->GetOverview(iOvrIdx), |
903 | 0 | nBaseBandOfMaskBand, iOvrIdx)); |
904 | 0 | } |
905 | 0 | } |
906 | 0 | } |
907 | 0 | else if (nBaseBandOfMaskBand > 0) |
908 | 0 | { |
909 | | // If we are a mask band, nstanciates a (thread-safe) mask band of |
910 | | // ourselves, but with the trick of negating nBaseBandOfMaskBand to |
911 | | // avoid infinite recursion... |
912 | 0 | m_poMaskBand = std::make_unique<GDALThreadSafeRasterBand>( |
913 | 0 | poTSDS, nullptr, 0, poPrototypeBand->GetMaskBand(), |
914 | 0 | -nBaseBandOfMaskBand, nOvrIdx); |
915 | 0 | } |
916 | 0 | } |
917 | | |
918 | | /************************************************************************/ |
919 | | /* RefUnderlyingRasterBand() */ |
920 | | /************************************************************************/ |
921 | | |
922 | | /** Implements GDALProxyRasterBand::RefUnderlyingDataset. |
923 | | * |
924 | | * This method is called by all virtual methods of GDALRasterBand overridden by |
925 | | * RefUnderlyingRasterBand() when it delegates the calls to the underlying |
926 | | * band. |
927 | | */ |
928 | | GDALRasterBand * |
929 | | GDALThreadSafeRasterBand::RefUnderlyingRasterBand(bool /*bForceOpen*/) const |
930 | 0 | { |
931 | | // Get a thread-local dataset |
932 | 0 | auto poTLDS = m_poTSDS->RefUnderlyingDataset(); |
933 | 0 | if (!poTLDS) |
934 | 0 | return nullptr; |
935 | | |
936 | | // Get corresponding thread-local band. If m_nBaseBandOfMaskBand is not |
937 | | // zero, then the base band is indicated into it, otherwise use nBand. |
938 | 0 | const int nTLSBandIdx = |
939 | 0 | m_nBaseBandOfMaskBand ? std::abs(m_nBaseBandOfMaskBand) : nBand; |
940 | 0 | auto poTLRasterBand = poTLDS->GetRasterBand(nTLSBandIdx); |
941 | 0 | if (!poTLRasterBand) |
942 | 0 | { |
943 | 0 | CPLError(CE_Failure, CPLE_AppDefined, |
944 | 0 | "GDALThreadSafeRasterBand::RefUnderlyingRasterBand(): " |
945 | 0 | "GetRasterBand(%d) failed", |
946 | 0 | nTLSBandIdx); |
947 | 0 | m_poTSDS->UnrefUnderlyingDataset(poTLDS); |
948 | 0 | return nullptr; |
949 | 0 | } |
950 | | |
951 | | // Get the overview level if needed. |
952 | 0 | if (m_nOvrIdx >= 0) |
953 | 0 | { |
954 | 0 | poTLRasterBand = poTLRasterBand->GetOverview(m_nOvrIdx); |
955 | 0 | if (!poTLRasterBand) |
956 | 0 | { |
957 | 0 | CPLError(CE_Failure, CPLE_AppDefined, |
958 | 0 | "GDALThreadSafeRasterBand::RefUnderlyingRasterBand(): " |
959 | 0 | "GetOverview(%d) failed", |
960 | 0 | m_nOvrIdx); |
961 | 0 | m_poTSDS->UnrefUnderlyingDataset(poTLDS); |
962 | 0 | return nullptr; |
963 | 0 | } |
964 | 0 | } |
965 | | |
966 | | // Get the mask band (or the mask band of the mask band) if needed. |
967 | 0 | if (m_nBaseBandOfMaskBand) |
968 | 0 | { |
969 | 0 | poTLRasterBand = poTLRasterBand->GetMaskBand(); |
970 | 0 | if (m_nBaseBandOfMaskBand < 0) |
971 | 0 | poTLRasterBand = poTLRasterBand->GetMaskBand(); |
972 | 0 | } |
973 | | |
974 | | // Check that the thread-local band characteristics are identical to the |
975 | | // ones of the prototype band. |
976 | 0 | if (m_poPrototypeBand->GetXSize() != poTLRasterBand->GetXSize() || |
977 | 0 | m_poPrototypeBand->GetYSize() != poTLRasterBand->GetYSize() || |
978 | 0 | m_poPrototypeBand->GetRasterDataType() != |
979 | 0 | poTLRasterBand->GetRasterDataType() |
980 | | // m_poPrototypeBand->GetMaskFlags() is not thread-safe |
981 | | // || m_poPrototypeBand->GetMaskFlags() != poTLRasterBand->GetMaskFlags() |
982 | 0 | ) |
983 | 0 | { |
984 | 0 | CPLError(CE_Failure, CPLE_AppDefined, |
985 | 0 | "GDALThreadSafeRasterBand::RefUnderlyingRasterBand(): TLS " |
986 | 0 | "band has not expected characteristics"); |
987 | 0 | m_poTSDS->UnrefUnderlyingDataset(poTLDS); |
988 | 0 | return nullptr; |
989 | 0 | } |
990 | 0 | int nThisBlockXSize; |
991 | 0 | int nThisBlockYSize; |
992 | 0 | int nTLSBlockXSize; |
993 | 0 | int nTLSBlockYSize; |
994 | 0 | m_poPrototypeBand->GetBlockSize(&nThisBlockXSize, &nThisBlockYSize); |
995 | 0 | poTLRasterBand->GetBlockSize(&nTLSBlockXSize, &nTLSBlockYSize); |
996 | 0 | if (nThisBlockXSize != nTLSBlockXSize || nThisBlockYSize != nTLSBlockYSize) |
997 | 0 | { |
998 | 0 | CPLError(CE_Failure, CPLE_AppDefined, |
999 | 0 | "GDALThreadSafeRasterBand::RefUnderlyingRasterBand(): TLS " |
1000 | 0 | "band has not expected characteristics"); |
1001 | 0 | m_poTSDS->UnrefUnderlyingDataset(poTLDS); |
1002 | 0 | return nullptr; |
1003 | 0 | } |
1004 | | |
1005 | | // Registers the association between the thread-local band and the |
1006 | | // thread-local dataset |
1007 | 0 | { |
1008 | 0 | GDALThreadLocalDatasetCache *poCache = |
1009 | 0 | GDALThreadSafeDataset::tl_poCache.get(); |
1010 | 0 | CPLAssert(poCache); |
1011 | 0 | std::unique_lock oLock(poCache->m_oMutex); |
1012 | 0 | CPLAssert(!cpl::contains(poCache->m_oMapReferencedDSFromBand, |
1013 | 0 | poTLRasterBand)); |
1014 | 0 | poCache->m_oMapReferencedDSFromBand[poTLRasterBand] = poTLDS; |
1015 | 0 | } |
1016 | | // CPLDebug("GDAL", "%p->RefUnderlyingRasterBand() return %p", this, poTLRasterBand); |
1017 | 0 | return poTLRasterBand; |
1018 | 0 | } |
1019 | | |
1020 | | /************************************************************************/ |
1021 | | /* UnrefUnderlyingRasterBand() */ |
1022 | | /************************************************************************/ |
1023 | | |
1024 | | /** Implements GDALProxyRasterBand::UnrefUnderlyingRasterBand. |
1025 | | * |
1026 | | * This is called by GDALProxyRasterBand overridden methods of GDALRasterBand, |
1027 | | * when they no longer need to access the underlying dataset. |
1028 | | */ |
1029 | | void GDALThreadSafeRasterBand::UnrefUnderlyingRasterBand( |
1030 | | GDALRasterBand *poUnderlyingRasterBand) const |
1031 | 0 | { |
1032 | | // CPLDebug("GDAL", "%p->UnrefUnderlyingRasterBand(%p)", this, poUnderlyingRasterBand); |
1033 | | |
1034 | | // Unregisters the association between the thread-local band and the |
1035 | | // thread-local dataset |
1036 | 0 | { |
1037 | 0 | GDALThreadLocalDatasetCache *poCache = |
1038 | 0 | GDALThreadSafeDataset::tl_poCache.get(); |
1039 | 0 | CPLAssert(poCache); |
1040 | 0 | std::unique_lock oLock(poCache->m_oMutex); |
1041 | 0 | auto oIter = |
1042 | 0 | poCache->m_oMapReferencedDSFromBand.find(poUnderlyingRasterBand); |
1043 | 0 | CPLAssert(oIter != poCache->m_oMapReferencedDSFromBand.end()); |
1044 | | |
1045 | 0 | m_poTSDS->UnrefUnderlyingDataset(oIter->second, poCache); |
1046 | 0 | poCache->m_oMapReferencedDSFromBand.erase(oIter); |
1047 | 0 | } |
1048 | 0 | } |
1049 | | |
1050 | | /************************************************************************/ |
1051 | | /* GetMaskBand() */ |
1052 | | /************************************************************************/ |
1053 | | |
1054 | | /** Implements GDALRasterBand::GetMaskBand |
1055 | | */ |
1056 | | GDALRasterBand *GDALThreadSafeRasterBand::GetMaskBand() |
1057 | 0 | { |
1058 | 0 | return m_poMaskBand ? m_poMaskBand.get() : this; |
1059 | 0 | } |
1060 | | |
1061 | | /************************************************************************/ |
1062 | | /* GetOverviewCount() */ |
1063 | | /************************************************************************/ |
1064 | | |
1065 | | /** Implements GDALRasterBand::GetOverviewCount |
1066 | | */ |
1067 | | int GDALThreadSafeRasterBand::GetOverviewCount() |
1068 | 0 | { |
1069 | 0 | return static_cast<int>(m_apoOverviews.size()); |
1070 | 0 | } |
1071 | | |
1072 | | /************************************************************************/ |
1073 | | /* GetOverview() */ |
1074 | | /************************************************************************/ |
1075 | | |
1076 | | /** Implements GDALRasterBand::GetOverview |
1077 | | */ |
1078 | | GDALRasterBand *GDALThreadSafeRasterBand::GetOverview(int nIdx) |
1079 | 0 | { |
1080 | 0 | if (nIdx < 0 || nIdx >= static_cast<int>(m_apoOverviews.size())) |
1081 | 0 | return nullptr; |
1082 | 0 | return m_apoOverviews[nIdx].get(); |
1083 | 0 | } |
1084 | | |
1085 | | /************************************************************************/ |
1086 | | /* GetRasterSampleOverview() */ |
1087 | | /************************************************************************/ |
1088 | | |
1089 | | /** Implements GDALRasterBand::GetRasterSampleOverview |
1090 | | */ |
1091 | | GDALRasterBand * |
1092 | | GDALThreadSafeRasterBand::GetRasterSampleOverview(GUIntBig nDesiredSamples) |
1093 | | |
1094 | 0 | { |
1095 | | // Call the base implementation, and do not forward to proxy |
1096 | 0 | return GDALRasterBand::GetRasterSampleOverview(nDesiredSamples); |
1097 | 0 | } |
1098 | | |
1099 | | /************************************************************************/ |
1100 | | /* GetDefaultRAT() */ |
1101 | | /************************************************************************/ |
1102 | | |
1103 | | /** Implements GDALRasterBand::GetDefaultRAT |
1104 | | * |
1105 | | * This is a bit tricky to do as GDALRasterAttributeTable has virtual methods |
1106 | | * with potential (non thread-safe) side-effects. The clean solution would be |
1107 | | * to implement a GDALThreadSafeRAT wrapper class, but this is a bit too much |
1108 | | * effort. So for now, we check if the RAT returned by the prototype band is |
1109 | | * an instance of GDALDefaultRasterAttributeTable. If it is, given that this |
1110 | | * class has thread-safe getters, we can directly return it. |
1111 | | * Otherwise return in error. |
1112 | | */ |
1113 | | GDALRasterAttributeTable *GDALThreadSafeRasterBand::GetDefaultRAT() |
1114 | 0 | { |
1115 | 0 | std::lock_guard oGuard(m_poTSDS->m_oPrototypeDSMutex); |
1116 | 0 | const auto poRAT = |
1117 | 0 | const_cast<GDALRasterBand *>(m_poPrototypeBand)->GetDefaultRAT(); |
1118 | 0 | if (!poRAT) |
1119 | 0 | return nullptr; |
1120 | | |
1121 | 0 | if (dynamic_cast<GDALDefaultRasterAttributeTable *>(poRAT)) |
1122 | 0 | return poRAT; |
1123 | | |
1124 | 0 | CPLError(CE_Failure, CPLE_AppDefined, |
1125 | 0 | "GDALThreadSafeRasterBand::GetDefaultRAT() not supporting a " |
1126 | 0 | "non-GDALDefaultRasterAttributeTable implementation"); |
1127 | 0 | return nullptr; |
1128 | 0 | } |
1129 | | |
1130 | | #endif // DOXYGEN_SKIP |
1131 | | |
1132 | | /************************************************************************/ |
1133 | | /* GDALDataset::IsThreadSafe() */ |
1134 | | /************************************************************************/ |
1135 | | |
1136 | | /** Return whether this dataset, and its related objects (typically raster |
1137 | | * bands), can be called for the intended scope. |
1138 | | * |
1139 | | * Note that in the current implementation, nScopeFlags should be set to |
1140 | | * GDAL_OF_RASTER, as thread-safety is limited to read-only operations and |
1141 | | * excludes operations on vector layers (OGRLayer) or multidimensional API |
1142 | | * (GDALGroup, GDALMDArray, etc.) |
1143 | | * |
1144 | | * This is the same as the C function GDALDatasetIsThreadSafe(). |
1145 | | * |
1146 | | * @since 3.10 |
1147 | | */ |
1148 | | bool GDALDataset::IsThreadSafe(int nScopeFlags) const |
1149 | 0 | { |
1150 | 0 | return (nOpenFlags & GDAL_OF_THREAD_SAFE) != 0 && |
1151 | 0 | nScopeFlags == GDAL_OF_RASTER && (nOpenFlags & GDAL_OF_RASTER) != 0; |
1152 | 0 | } |
1153 | | |
1154 | | /************************************************************************/ |
1155 | | /* GDALDatasetIsThreadSafe() */ |
1156 | | /************************************************************************/ |
1157 | | |
1158 | | /** Return whether this dataset, and its related objects (typically raster |
1159 | | * bands), can be called for the intended scope. |
1160 | | * |
1161 | | * Note that in the current implementation, nScopeFlags should be set to |
1162 | | * GDAL_OF_RASTER, as thread-safety is limited to read-only operations and |
1163 | | * excludes operations on vector layers (OGRLayer) or multidimensional API |
1164 | | * (GDALGroup, GDALMDArray, etc.) |
1165 | | * |
1166 | | * This is the same as the C++ method GDALDataset::IsThreadSafe(). |
1167 | | * |
1168 | | * @param hDS Source dataset |
1169 | | * @param nScopeFlags Intended scope of use. |
1170 | | * Only GDAL_OF_RASTER is supported currently. |
1171 | | * @param papszOptions Options. None currently. |
1172 | | * |
1173 | | * @since 3.10 |
1174 | | */ |
1175 | | bool GDALDatasetIsThreadSafe(GDALDatasetH hDS, int nScopeFlags, |
1176 | | CSLConstList papszOptions) |
1177 | 0 | { |
1178 | 0 | VALIDATE_POINTER1(hDS, __func__, false); |
1179 | | |
1180 | 0 | CPL_IGNORE_RET_VAL(papszOptions); |
1181 | |
|
1182 | 0 | return GDALDataset::FromHandle(hDS)->IsThreadSafe(nScopeFlags); |
1183 | 0 | } |
1184 | | |
1185 | | /************************************************************************/ |
1186 | | /* GDALGetThreadSafeDataset() */ |
1187 | | /************************************************************************/ |
1188 | | |
1189 | | /** Return a thread-safe dataset. |
1190 | | * |
1191 | | * In the general case, this thread-safe dataset will open a |
1192 | | * behind-the-scenes per-thread dataset (reusing the name and open options of poDS), |
1193 | | * the first time a thread calls a method on the thread-safe dataset, and will |
1194 | | * transparently redirect calls from the calling thread to this behind-the-scenes |
1195 | | * per-thread dataset. Hence there is an initial setup cost per thread. |
1196 | | * Datasets of the MEM driver cannot be opened by name, but this function will |
1197 | | * take care of "cloning" them, using the same backing memory, when needed. |
1198 | | * |
1199 | | * Ownership of the passed dataset is transferred to the thread-safe dataset. |
1200 | | * |
1201 | | * The function may also return the passed dataset if it is already thread-safe. |
1202 | | * |
1203 | | * @param poDS Source dataset |
1204 | | * @param nScopeFlags Intended scope of use. |
1205 | | * Only GDAL_OF_RASTER is supported currently. |
1206 | | * |
1207 | | * @return a new thread-safe dataset, or nullptr in case of error. |
1208 | | * |
1209 | | * @since 3.10 |
1210 | | */ |
1211 | | std::unique_ptr<GDALDataset> |
1212 | | GDALGetThreadSafeDataset(std::unique_ptr<GDALDataset> poDS, int nScopeFlags) |
1213 | 0 | { |
1214 | 0 | return GDALThreadSafeDataset::Create(std::move(poDS), nScopeFlags); |
1215 | 0 | } |
1216 | | |
1217 | | /************************************************************************/ |
1218 | | /* GDALGetThreadSafeDataset() */ |
1219 | | /************************************************************************/ |
1220 | | |
1221 | | /** Return a thread-safe dataset. |
1222 | | * |
1223 | | * In the general case, this thread-safe dataset will open a |
1224 | | * behind-the-scenes per-thread dataset (reusing the name and open options of poDS), |
1225 | | * the first time a thread calls a method on the thread-safe dataset, and will |
1226 | | * transparently redirect calls from the calling thread to this behind-the-scenes |
1227 | | * per-thread dataset. Hence there is an initial setup cost per thread. |
1228 | | * Datasets of the MEM driver cannot be opened by name, but this function will |
1229 | | * take care of "cloning" them, using the same backing memory, when needed. |
1230 | | * |
1231 | | * The life-time of the passed dataset must be longer than the one of |
1232 | | * the returned thread-safe dataset. |
1233 | | * |
1234 | | * Note that this function does increase the reference count on poDS while |
1235 | | * it is being used |
1236 | | * |
1237 | | * The function may also return the passed dataset if it is already thread-safe. |
1238 | | * A non-nullptr returned dataset must be released with ReleaseRef(). |
1239 | | * |
1240 | | * Patterns like the following one are valid: |
1241 | | * \code{.cpp} |
1242 | | * auto poDS = GDALDataset::Open(...); |
1243 | | * auto poThreadSafeDS = GDALGetThreadSafeDataset(poDS, GDAL_OF_RASTER | GDAL_OF_THREAD_SAFE); |
1244 | | * poDS->ReleaseRef(); |
1245 | | * if (poThreadSafeDS ) |
1246 | | * { |
1247 | | * // ... do something with poThreadSafeDS ... |
1248 | | * poThreadSafeDS->ReleaseRef(); |
1249 | | * } |
1250 | | * \endcode |
1251 | | * |
1252 | | * @param poDS Source dataset |
1253 | | * @param nScopeFlags Intended scope of use. |
1254 | | * Only GDAL_OF_RASTER is supported currently. |
1255 | | * |
1256 | | * @return a new thread-safe dataset or poDS, or nullptr in case of error. |
1257 | | |
1258 | | * @since 3.10 |
1259 | | */ |
1260 | | GDALDataset *GDALGetThreadSafeDataset(GDALDataset *poDS, int nScopeFlags) |
1261 | 0 | { |
1262 | 0 | return GDALThreadSafeDataset::Create(poDS, nScopeFlags); |
1263 | 0 | } |
1264 | | |
1265 | | /************************************************************************/ |
1266 | | /* GDALGetThreadSafeDataset() */ |
1267 | | /************************************************************************/ |
1268 | | |
1269 | | /** Return a thread-safe dataset. |
1270 | | * |
1271 | | * In the general case, this thread-safe dataset will open a |
1272 | | * behind-the-scenes per-thread dataset (reusing the name and open options of hDS), |
1273 | | * the first time a thread calls a method on the thread-safe dataset, and will |
1274 | | * transparently redirect calls from the calling thread to this behind-the-scenes |
1275 | | * per-thread dataset. Hence there is an initial setup cost per thread. |
1276 | | * Datasets of the MEM driver cannot be opened by name, but this function will |
1277 | | * take care of "cloning" them, using the same backing memory, when needed. |
1278 | | * |
1279 | | * The life-time of the passed dataset must be longer than the one of |
1280 | | * the returned thread-safe dataset. |
1281 | | * |
1282 | | * Note that this function does increase the reference count on poDS while |
1283 | | * it is being used |
1284 | | * |
1285 | | * The function may also return the passed dataset if it is already thread-safe. |
1286 | | * A non-nullptr returned dataset must be released with GDALReleaseDataset(). |
1287 | | * |
1288 | | * \code{.cpp} |
1289 | | * hDS = GDALOpenEx(...); |
1290 | | * hThreadSafeDS = GDALGetThreadSafeDataset(hDS, GDAL_OF_RASTER | GDAL_OF_THREAD_SAFE, NULL); |
1291 | | * GDALReleaseDataset(hDS); |
1292 | | * if( hThreadSafeDS ) |
1293 | | * { |
1294 | | * // ... do something with hThreadSafeDS ... |
1295 | | * GDALReleaseDataset(hThreadSafeDS); |
1296 | | * } |
1297 | | * \endcode |
1298 | | * |
1299 | | * @param hDS Source dataset |
1300 | | * @param nScopeFlags Intended scope of use. |
1301 | | * Only GDAL_OF_RASTER is supported currently. |
1302 | | * @param papszOptions Options. None currently. |
1303 | | * |
1304 | | * @since 3.10 |
1305 | | */ |
1306 | | GDALDatasetH GDALGetThreadSafeDataset(GDALDatasetH hDS, int nScopeFlags, |
1307 | | CSLConstList papszOptions) |
1308 | 0 | { |
1309 | 0 | VALIDATE_POINTER1(hDS, __func__, nullptr); |
1310 | | |
1311 | 0 | CPL_IGNORE_RET_VAL(papszOptions); |
1312 | 0 | return GDALDataset::ToHandle( |
1313 | 0 | GDALGetThreadSafeDataset(GDALDataset::FromHandle(hDS), nScopeFlags)); |
1314 | 0 | } |