/src/PROJ/curl/lib/bufq.c

Source (jump to first uncovered line)
/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution. The terms
 * are also available at https://curl.se/docs/copyright.html.
 *
 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 * copies of the Software, and permit persons to whom the Software is
 * furnished to do so, under the terms of the COPYING file.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 * SPDX-License-Identifier: curl
 *
 ***************************************************************************/

#include "curl_setup.h"
#include "bufq.h"

/* The last 3 #include files should be in this order */
#include "curl_printf.h"
#include "curl_memory.h"
#include "memdebug.h"

static bool chunk_is_empty(const struct buf_chunk *chunk)
{
  return chunk->r_offset >= chunk->w_offset;
}

static bool chunk_is_full(const struct buf_chunk *chunk)
{
  return chunk->w_offset >= chunk->dlen;
}

static size_t chunk_len(const struct buf_chunk *chunk)
{
  return chunk->w_offset - chunk->r_offset;
}

static void chunk_reset(struct buf_chunk *chunk)
{
  chunk->next = NULL;
  chunk->r_offset = chunk->w_offset = 0;
}

static size_t chunk_append(struct buf_chunk *chunk,
                           const unsigned char *buf, size_t len)
{
  unsigned char *p = &chunk->x.data[chunk->w_offset];
  size_t n = chunk->dlen - chunk->w_offset;
  DEBUGASSERT(chunk->dlen >= chunk->w_offset);
  if(n) {
    n = CURLMIN(n, len);
    memcpy(p, buf, n);
    chunk->w_offset += n;
  }
  return n;
}

static size_t chunk_read(struct buf_chunk *chunk,
                         unsigned char *buf, size_t len)
{
  unsigned char *p = &chunk->x.data[chunk->r_offset];
  size_t n = chunk->w_offset - chunk->r_offset;
  DEBUGASSERT(chunk->w_offset >= chunk->r_offset);
  if(!n) {
    return 0;
  }
  else if(n <= len) {
    memcpy(buf, p, n);
    chunk->r_offset = chunk->w_offset = 0;
    return n;
  }
  else {
    memcpy(buf, p, len);
    chunk->r_offset += len;
    return len;
  }
}

static CURLcode chunk_slurpn(struct buf_chunk *chunk, size_t max_len,
                             Curl_bufq_reader *reader,
                             void *reader_ctx, size_t *pnread)
{
  unsigned char *p = &chunk->x.data[chunk->w_offset];
  size_t n = chunk->dlen - chunk->w_offset; /* free amount */
  CURLcode result;

  *pnread = 0;
  DEBUGASSERT(chunk->dlen >= chunk->w_offset);
  if(!n)
    return CURLE_AGAIN;
  if(max_len && n > max_len)
    n = max_len;
  result = reader(reader_ctx, p, n, pnread);
  if(!result) {
    DEBUGASSERT(*pnread <= n);
    chunk->w_offset += *pnread;
  }
  return result;
}

static void chunk_peek(const struct buf_chunk *chunk,
                       const unsigned char **pbuf, size_t *plen)
{
  DEBUGASSERT(chunk->w_offset >= chunk->r_offset);
  *pbuf = &chunk->x.data[chunk->r_offset];
  *plen = chunk->w_offset - chunk->r_offset;
}

static void chunk_peek_at(const struct buf_chunk *chunk, size_t offset,
                          const unsigned char **pbuf, size_t *plen)
{
  offset += chunk->r_offset;
  DEBUGASSERT(chunk->w_offset >= offset);
  *pbuf = &chunk->x.data[offset];
  *plen = chunk->w_offset - offset;
}

static size_t chunk_skip(struct buf_chunk *chunk, size_t amount)
{
  size_t n = chunk->w_offset - chunk->r_offset;
  DEBUGASSERT(chunk->w_offset >= chunk->r_offset);
  if(n) {
    n = CURLMIN(n, amount);
    chunk->r_offset += n;
    if(chunk->r_offset == chunk->w_offset)
      chunk->r_offset = chunk->w_offset = 0;
  }
  return n;
}

static void chunk_list_free(struct buf_chunk **anchor)
{
  struct buf_chunk *chunk;
  while(*anchor) {
    chunk = *anchor;
    *anchor = chunk->next;
    free(chunk);
  }
}



void Curl_bufcp_init(struct bufc_pool *pool,
                     size_t chunk_size, size_t spare_max)
{
  DEBUGASSERT(chunk_size > 0);
  DEBUGASSERT(spare_max > 0);
  memset(pool, 0, sizeof(*pool));
  pool->chunk_size = chunk_size;
  pool->spare_max = spare_max;
}

static CURLcode bufcp_take(struct bufc_pool *pool,
                           struct buf_chunk **pchunk)
{
  struct buf_chunk *chunk = NULL;

  if(pool->spare) {
    chunk = pool->spare;
    pool->spare = chunk->next;
    --pool->spare_count;
    chunk_reset(chunk);
    *pchunk = chunk;
    return CURLE_OK;
  }

  chunk = calloc(1, sizeof(*chunk) + pool->chunk_size);
  if(!chunk) {
    *pchunk = NULL;
    return CURLE_OUT_OF_MEMORY;
  }
  chunk->dlen = pool->chunk_size;
  *pchunk = chunk;
  return CURLE_OK;
}

static void bufcp_put(struct bufc_pool *pool,
                      struct buf_chunk *chunk)
{
  if(pool->spare_count >= pool->spare_max) {
    free(chunk);
  }
  else {
    chunk_reset(chunk);
    chunk->next = pool->spare;
    pool->spare = chunk;
    ++pool->spare_count;
  }
}

void Curl_bufcp_free(struct bufc_pool *pool)
{
  chunk_list_free(&pool->spare);
  pool->spare_count = 0;
}

static void bufq_init(struct bufq *q, struct bufc_pool *pool,
                      size_t chunk_size, size_t max_chunks, int opts)
{
  DEBUGASSERT(chunk_size > 0);
  DEBUGASSERT(max_chunks > 0);
  memset(q, 0, sizeof(*q));
  q->chunk_size = chunk_size;
  q->max_chunks = max_chunks;
  q->pool = pool;
  q->opts = opts;
}

void Curl_bufq_init2(struct bufq *q, size_t chunk_size, size_t max_chunks,
                     int opts)
{
  bufq_init(q, NULL, chunk_size, max_chunks, opts);
}

void Curl_bufq_init(struct bufq *q, size_t chunk_size, size_t max_chunks)
{
  bufq_init(q, NULL, chunk_size, max_chunks, BUFQ_OPT_NONE);
}

void Curl_bufq_initp(struct bufq *q, struct bufc_pool *pool,
                     size_t max_chunks, int opts)
{
  bufq_init(q, pool, pool->chunk_size, max_chunks, opts);
}

void Curl_bufq_free(struct bufq *q)
{
  chunk_list_free(&q->head);
  chunk_list_free(&q->spare);
  q->tail = NULL;
  q->chunk_count = 0;
}

void Curl_bufq_reset(struct bufq *q)
{
  struct buf_chunk *chunk;
  while(q->head) {
    chunk = q->head;
    q->head = chunk->next;
    chunk->next = q->spare;
    q->spare = chunk;
  }
  q->tail = NULL;
}

size_t Curl_bufq_len(const struct bufq *q)
{
  const struct buf_chunk *chunk = q->head;
  size_t len = 0;
  while(chunk) {
    len += chunk_len(chunk);
    chunk = chunk->next;
  }
  return len;
}

bool Curl_bufq_is_empty(const struct bufq *q)
{
  return !q->head || chunk_is_empty(q->head);
}

bool Curl_bufq_is_full(const struct bufq *q)
{
  if(!q->tail || q->spare)
    return FALSE;
  if(q->chunk_count < q->max_chunks)
    return FALSE;
  if(q->chunk_count > q->max_chunks)
    return TRUE;
  /* we have no spares and cannot make more, is the tail full? */
  return chunk_is_full(q->tail);
}

static struct buf_chunk *get_spare(struct bufq *q)
{
  struct buf_chunk *chunk = NULL;

  if(q->spare) {
    chunk = q->spare;
    q->spare = chunk->next;
    chunk_reset(chunk);
    return chunk;
  }

  if(q->chunk_count >= q->max_chunks && (!(q->opts & BUFQ_OPT_SOFT_LIMIT)))
    return NULL;

  if(q->pool) {
    if(bufcp_take(q->pool, &chunk))
      return NULL;
    ++q->chunk_count;
    return chunk;
  }
  else {
    chunk = calloc(1, sizeof(*chunk) + q->chunk_size);
    if(!chunk)
      return NULL;
    chunk->dlen = q->chunk_size;
    ++q->chunk_count;
    return chunk;
  }
}

static void prune_head(struct bufq *q)
{
  struct buf_chunk *chunk;

  while(q->head && chunk_is_empty(q->head)) {
    chunk = q->head;
    q->head = chunk->next;
    if(q->tail == chunk)
      q->tail = q->head;
    if(q->pool) {
      bufcp_put(q->pool, chunk);
      --q->chunk_count;
    }
    else if((q->chunk_count > q->max_chunks) ||
       (q->opts & BUFQ_OPT_NO_SPARES)) {
      /* SOFT_LIMIT allowed us more than max. free spares until
       * we are at max again. Or free them if we are configured
       * to not use spares. */
      free(chunk);
      --q->chunk_count;
    }
    else {
      chunk->next = q->spare;
      q->spare = chunk;
    }
  }
}

static struct buf_chunk *get_non_full_tail(struct bufq *q)
{
  struct buf_chunk *chunk;

  if(q->tail && !chunk_is_full(q->tail))
    return q->tail;
  chunk = get_spare(q);
  if(chunk) {
    /* new tail, and possibly new head */
    if(q->tail) {
      q->tail->next = chunk;
      q->tail = chunk;
    }
    else {
      DEBUGASSERT(!q->head);
      q->head = q->tail = chunk;
    }
  }
  return chunk;
}

CURLcode Curl_bufq_write(struct bufq *q,
                         const unsigned char *buf, size_t len,
                         size_t *pnwritten)
{
  struct buf_chunk *tail;
  size_t n;

  DEBUGASSERT(q->max_chunks > 0);
  *pnwritten = 0;
  while(len) {
    tail = get_non_full_tail(q);
    if(!tail) {
      if((q->chunk_count < q->max_chunks) || (q->opts & BUFQ_OPT_SOFT_LIMIT))
        /* should have gotten a tail, but did not */
        return CURLE_OUT_OF_MEMORY;
      break;
    }
    n = chunk_append(tail, buf, len);
    if(!n)
      break;
    *pnwritten += n;
    buf += n;
    len -= n;
  }
  return (!*pnwritten && len) ? CURLE_AGAIN : CURLE_OK;
}

CURLcode Curl_bufq_cwrite(struct bufq *q,
                          const char *buf, size_t len,
                          size_t *pnwritten)
{
  return Curl_bufq_write(q, (const unsigned char *)buf, len, pnwritten);
}

CURLcode Curl_bufq_read(struct bufq *q, unsigned char *buf, size_t len,
                        size_t *pnread)
{
  *pnread = 0;
  while(len && q->head) {
    size_t n = chunk_read(q->head, buf, len);
    if(n) {
      *pnread += n;
      buf += n;
      len -= n;
    }
    prune_head(q);
  }
  return (!*pnread) ? CURLE_AGAIN : CURLE_OK;
}

CURLcode Curl_bufq_cread(struct bufq *q, char *buf, size_t len,
                         size_t *pnread)
{
  return Curl_bufq_read(q, (unsigned char *)buf, len, pnread);
}

bool Curl_bufq_peek(struct bufq *q,
                    const unsigned char **pbuf, size_t *plen)
{
  if(q->head && chunk_is_empty(q->head)) {
    prune_head(q);
  }
  if(q->head && !chunk_is_empty(q->head)) {
    chunk_peek(q->head, pbuf, plen);
    return TRUE;
  }
  *pbuf = NULL;
  *plen = 0;
  return FALSE;
}

bool Curl_bufq_peek_at(struct bufq *q, size_t offset,
                       const unsigned char **pbuf, size_t *plen)
{
  struct buf_chunk *c = q->head;
  size_t clen;

  while(c) {
    clen = chunk_len(c);
    if(!clen)
      break;
    if(offset >= clen) {
      offset -= clen;
      c = c->next;
      continue;
    }
    chunk_peek_at(c, offset, pbuf, plen);
    return TRUE;
  }
  *pbuf = NULL;
  *plen = 0;
  return FALSE;
}

void Curl_bufq_skip(struct bufq *q, size_t amount)
{
  size_t n;

  while(amount && q->head) {
    n = chunk_skip(q->head, amount);
    amount -= n;
    prune_head(q);
  }
}

CURLcode Curl_bufq_pass(struct bufq *q, Curl_bufq_writer *writer,
                        void *writer_ctx, size_t *pwritten)
{
  const unsigned char *buf;
  size_t blen;
  CURLcode result = CURLE_OK;

  *pwritten = 0;
  while(Curl_bufq_peek(q, &buf, &blen)) {
    size_t chunk_written;

    result = writer(writer_ctx, buf, blen, &chunk_written);
    if(result) {
      if((result == CURLE_AGAIN) && *pwritten) {
        /* blocked on subsequent write, report success */
        result = CURLE_OK;
      }
      break;
    }
    if(!chunk_written) {
      if(!*pwritten) {
        /* treat as blocked */
        result = CURLE_AGAIN;
      }
      break;
    }
    *pwritten += chunk_written;
    Curl_bufq_skip(q, chunk_written);
  }
  return result;
}

CURLcode Curl_bufq_write_pass(struct bufq *q,
                              const unsigned char *buf, size_t len,
                              Curl_bufq_writer *writer, void *writer_ctx,
                              size_t *pwritten)
{
  CURLcode result = CURLE_OK;
  size_t n;

  *pwritten = 0;
  while(len) {
    if(Curl_bufq_is_full(q)) {
      /* try to make room in case we are full */
      result = Curl_bufq_pass(q, writer, writer_ctx, &n);
      if(result) {
        if(result != CURLE_AGAIN) {
          /* real error, fail */
          return result;
        }
        /* would block, bufq is full, give up */
        break;
      }
    }

    /* Add to bufq as much as there is room for */
    result = Curl_bufq_write(q, buf, len, &n);
    if(result) {
      if(result != CURLE_AGAIN)
        /* real error, fail */
        return result;
      if((result == CURLE_AGAIN) && *pwritten)
        /* we did write successfully before */
        result = CURLE_OK;
      return result;
    }
    else if(n == 0)
      /* edge case of writer returning 0 (and len is >0)
       * break or we might enter an infinite loop here */
      break;

    /* Track what we added to bufq */
    buf += n;
    len -= n;
    *pwritten += n;
  }

  return (!*pwritten && len) ? CURLE_AGAIN : CURLE_OK;
}

CURLcode Curl_bufq_sipn(struct bufq *q, size_t max_len,
                        Curl_bufq_reader *reader, void *reader_ctx,
                        size_t *pnread)
{
  struct buf_chunk *tail = NULL;

  *pnread = 0;
  tail = get_non_full_tail(q);
  if(!tail) {
    if(q->chunk_count < q->max_chunks)
      return CURLE_OUT_OF_MEMORY;
    /* full, blocked */
    return CURLE_AGAIN;
  }

  return chunk_slurpn(tail, max_len, reader, reader_ctx, pnread);
}

/**
 * Read up to `max_len` bytes and append it to the end of the buffer queue.
 * if `max_len` is 0, no limit is imposed and the call behaves exactly
 * the same as `Curl_bufq_slurp()`.
 * Returns the total amount of buf read (may be 0) in `pnread` or error
 * Note that even in case of an error chunks may have been read and
 * the buffer queue will have different length than before.
 */
static CURLcode bufq_slurpn(struct bufq *q, size_t max_len,
                            Curl_bufq_reader *reader, void *reader_ctx,
                            size_t *pnread)
{
  CURLcode result;

  *pnread = 0;
  while(1) {
    size_t n;
    result = Curl_bufq_sipn(q, max_len, reader, reader_ctx, &n);
    if(result) {
      if(!*pnread || result != CURLE_AGAIN) {
        /* blocked on first read or real error, fail */
        return result;
      }
      result = CURLE_OK;
      break;
    }
    else if(n == 0) {
      /* eof */
      result = CURLE_OK;
      break;
    }
    *pnread += n;
    if(max_len) {
      DEBUGASSERT(n <= max_len);
      max_len -= n;
      if(!max_len)
        break;
    }
    /* give up slurping when we get less bytes than we asked for */
    if(q->tail && !chunk_is_full(q->tail))
      break;
  }
  return result;
}

CURLcode Curl_bufq_slurp(struct bufq *q, Curl_bufq_reader *reader,
                         void *reader_ctx, size_t *pnread)
{
  return bufq_slurpn(q, 0, reader, reader_ctx, pnread);
}

Coverage Report

Created: 2025-07-11 06:33

Line	Count	Source (jump to first uncovered line)
1		/***************************************************************************
2		* _ _ ____ _
3		* Project ___\| \| \| \| _ \\| \|
4		* / __\| \| \| \| \|_) \| \|
5		* \| (__\| \|_\| \| _ <\| \|___
6		* \___\|\___/\|_\| \_\_____\|
7		*
8		* Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
9		*
10		* This software is licensed as described in the file COPYING, which
11		* you should have received as part of this distribution. The terms
12		* are also available at https://curl.se/docs/copyright.html.
13		*
14		* You may opt to use, copy, modify, merge, publish, distribute and/or sell
15		* copies of the Software, and permit persons to whom the Software is
16		* furnished to do so, under the terms of the COPYING file.
17		*
18		* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19		* KIND, either express or implied.
20		*
21		* SPDX-License-Identifier: curl
22		*
23		***************************************************************************/
24
25		#include "curl_setup.h"
26		#include "bufq.h"
27
28		/* The last 3 #include files should be in this order */
29		#include "curl_printf.h"
30		#include "curl_memory.h"
31		#include "memdebug.h"
32
33		static bool chunk_is_empty(const struct buf_chunk *chunk)
34	0	{
35	0	return chunk->r_offset >= chunk->w_offset;
36	0	}
37
38		static bool chunk_is_full(const struct buf_chunk *chunk)
39	0	{
40	0	return chunk->w_offset >= chunk->dlen;
41	0	}
42
43		static size_t chunk_len(const struct buf_chunk *chunk)
44	0	{
45	0	return chunk->w_offset - chunk->r_offset;
46	0	}
47
48		static void chunk_reset(struct buf_chunk *chunk)
49	0	{
50	0	chunk->next = NULL;
51	0	chunk->r_offset = chunk->w_offset = 0;
52	0	}
53
54		static size_t chunk_append(struct buf_chunk *chunk,
55		const unsigned char *buf, size_t len)
56	0	{
57	0	unsigned char *p = &chunk->x.data[chunk->w_offset];
58	0	size_t n = chunk->dlen - chunk->w_offset;
59	0	DEBUGASSERT(chunk->dlen >= chunk->w_offset);
60	0	if(n) {
61	0	n = CURLMIN(n, len);
62	0	memcpy(p, buf, n);
63	0	chunk->w_offset += n;
64	0	}
65	0	return n;
66	0	}
67
68		static size_t chunk_read(struct buf_chunk *chunk,
69		unsigned char *buf, size_t len)
70	0	{
71	0	unsigned char *p = &chunk->x.data[chunk->r_offset];
72	0	size_t n = chunk->w_offset - chunk->r_offset;
73	0	DEBUGASSERT(chunk->w_offset >= chunk->r_offset);
74	0	if(!n) {
75	0	return 0;
76	0	}
77	0	else if(n <= len) {
78	0	memcpy(buf, p, n);
79	0	chunk->r_offset = chunk->w_offset = 0;
80	0	return n;
81	0	}
82	0	else {
83	0	memcpy(buf, p, len);
84	0	chunk->r_offset += len;
85	0	return len;
86	0	}
87	0	}
88
89		static CURLcode chunk_slurpn(struct buf_chunk *chunk, size_t max_len,
90		Curl_bufq_reader *reader,
91		void reader_ctx, size_t pnread)
92	0	{
93	0	unsigned char *p = &chunk->x.data[chunk->w_offset];
94	0	size_t n = chunk->dlen - chunk->w_offset; /* free amount */
95	0	CURLcode result;
96
97	0	*pnread = 0;
98	0	DEBUGASSERT(chunk->dlen >= chunk->w_offset);
99	0	if(!n)
100	0	return CURLE_AGAIN;
101	0	if(max_len && n > max_len)
102	0	n = max_len;
103	0	result = reader(reader_ctx, p, n, pnread);
104	0	if(!result) {
105	0	DEBUGASSERT(*pnread <= n);
106	0	chunk->w_offset += *pnread;
107	0	}
108	0	return result;
109	0	}
110
111		static void chunk_peek(const struct buf_chunk *chunk,
112		const unsigned char *pbuf, size_t plen)
113	0	{
114	0	DEBUGASSERT(chunk->w_offset >= chunk->r_offset);
115	0	*pbuf = &chunk->x.data[chunk->r_offset];
116	0	*plen = chunk->w_offset - chunk->r_offset;
117	0	}
118
119		static void chunk_peek_at(const struct buf_chunk *chunk, size_t offset,
120		const unsigned char *pbuf, size_t plen)
121	0	{
122	0	offset += chunk->r_offset;
123	0	DEBUGASSERT(chunk->w_offset >= offset);
124	0	*pbuf = &chunk->x.data[offset];
125	0	*plen = chunk->w_offset - offset;
126	0	}
127
128		static size_t chunk_skip(struct buf_chunk *chunk, size_t amount)
129	0	{
130	0	size_t n = chunk->w_offset - chunk->r_offset;
131	0	DEBUGASSERT(chunk->w_offset >= chunk->r_offset);
132	0	if(n) {
133	0	n = CURLMIN(n, amount);
134	0	chunk->r_offset += n;
135	0	if(chunk->r_offset == chunk->w_offset)
136	0	chunk->r_offset = chunk->w_offset = 0;
137	0	}
138	0	return n;
139	0	}
140
141		static void chunk_list_free(struct buf_chunk **anchor)
142	0	{
143	0	struct buf_chunk *chunk;
144	0	while(*anchor) {
145	0	chunk = *anchor;
146	0	*anchor = chunk->next;
147	0	free(chunk);
148	0	}
149	0	}
150
151
152
153		void Curl_bufcp_init(struct bufc_pool *pool,
154		size_t chunk_size, size_t spare_max)
155	0	{
156	0	DEBUGASSERT(chunk_size > 0);
157	0	DEBUGASSERT(spare_max > 0);
158	0	memset(pool, 0, sizeof(*pool));
159	0	pool->chunk_size = chunk_size;
160	0	pool->spare_max = spare_max;
161	0	}
162
163		static CURLcode bufcp_take(struct bufc_pool *pool,
164		struct buf_chunk **pchunk)
165	0	{
166	0	struct buf_chunk *chunk = NULL;
167
168	0	if(pool->spare) {
169	0	chunk = pool->spare;
170	0	pool->spare = chunk->next;
171	0	--pool->spare_count;
172	0	chunk_reset(chunk);
173	0	*pchunk = chunk;
174	0	return CURLE_OK;
175	0	}
176
177	0	chunk = calloc(1, sizeof(*chunk) + pool->chunk_size);
178	0	if(!chunk) {
179	0	*pchunk = NULL;
180	0	return CURLE_OUT_OF_MEMORY;
181	0	}
182	0	chunk->dlen = pool->chunk_size;
183	0	*pchunk = chunk;
184	0	return CURLE_OK;
185	0	}
186
187		static void bufcp_put(struct bufc_pool *pool,
188		struct buf_chunk *chunk)
189	0	{
190	0	if(pool->spare_count >= pool->spare_max) {
191	0	free(chunk);
192	0	}
193	0	else {
194	0	chunk_reset(chunk);
195	0	chunk->next = pool->spare;
196	0	pool->spare = chunk;
197	0	++pool->spare_count;
198	0	}
199	0	}
200
201		void Curl_bufcp_free(struct bufc_pool *pool)
202	0	{
203	0	chunk_list_free(&pool->spare);
204	0	pool->spare_count = 0;
205	0	}
206
207		static void bufq_init(struct bufq q, struct bufc_pool pool,
208		size_t chunk_size, size_t max_chunks, int opts)
209	0	{
210	0	DEBUGASSERT(chunk_size > 0);
211	0	DEBUGASSERT(max_chunks > 0);
212	0	memset(q, 0, sizeof(*q));
213	0	q->chunk_size = chunk_size;
214	0	q->max_chunks = max_chunks;
215	0	q->pool = pool;
216	0	q->opts = opts;
217	0	}
218
219		void Curl_bufq_init2(struct bufq *q, size_t chunk_size, size_t max_chunks,
220		int opts)
221	0	{
222	0	bufq_init(q, NULL, chunk_size, max_chunks, opts);
223	0	}
224
225		void Curl_bufq_init(struct bufq *q, size_t chunk_size, size_t max_chunks)
226	0	{
227	0	bufq_init(q, NULL, chunk_size, max_chunks, BUFQ_OPT_NONE);
228	0	}
229
230		void Curl_bufq_initp(struct bufq q, struct bufc_pool pool,
231		size_t max_chunks, int opts)
232	0	{
233	0	bufq_init(q, pool, pool->chunk_size, max_chunks, opts);
234	0	}
235
236		void Curl_bufq_free(struct bufq *q)
237	0	{
238	0	chunk_list_free(&q->head);
239	0	chunk_list_free(&q->spare);
240	0	q->tail = NULL;
241	0	q->chunk_count = 0;
242	0	}
243
244		void Curl_bufq_reset(struct bufq *q)
245	0	{
246	0	struct buf_chunk *chunk;
247	0	while(q->head) {
248	0	chunk = q->head;
249	0	q->head = chunk->next;
250	0	chunk->next = q->spare;
251	0	q->spare = chunk;
252	0	}
253	0	q->tail = NULL;
254	0	}
255
256		size_t Curl_bufq_len(const struct bufq *q)
257	0	{
258	0	const struct buf_chunk *chunk = q->head;
259	0	size_t len = 0;
260	0	while(chunk) {
261	0	len += chunk_len(chunk);
262	0	chunk = chunk->next;
263	0	}
264	0	return len;
265	0	}
266
267		bool Curl_bufq_is_empty(const struct bufq *q)
268	0	{
269	0	return !q->head \|\| chunk_is_empty(q->head);
270	0	}
271
272		bool Curl_bufq_is_full(const struct bufq *q)
273	0	{
274	0	if(!q->tail \|\| q->spare)
275	0	return FALSE;
276	0	if(q->chunk_count < q->max_chunks)
277	0	return FALSE;
278	0	if(q->chunk_count > q->max_chunks)
279	0	return TRUE;
280		/* we have no spares and cannot make more, is the tail full? */
281	0	return chunk_is_full(q->tail);
282	0	}
283
284		static struct buf_chunk get_spare(struct bufq q)
285	0	{
286	0	struct buf_chunk *chunk = NULL;
287
288	0	if(q->spare) {
289	0	chunk = q->spare;
290	0	q->spare = chunk->next;
291	0	chunk_reset(chunk);
292	0	return chunk;
293	0	}
294
295	0	if(q->chunk_count >= q->max_chunks && (!(q->opts & BUFQ_OPT_SOFT_LIMIT)))
296	0	return NULL;
297
298	0	if(q->pool) {
299	0	if(bufcp_take(q->pool, &chunk))
300	0	return NULL;
301	0	++q->chunk_count;
302	0	return chunk;
303	0	}
304	0	else {
305	0	chunk = calloc(1, sizeof(*chunk) + q->chunk_size);
306	0	if(!chunk)
307	0	return NULL;
308	0	chunk->dlen = q->chunk_size;
309	0	++q->chunk_count;
310	0	return chunk;
311	0	}
312	0	}
313
314		static void prune_head(struct bufq *q)
315	0	{
316	0	struct buf_chunk *chunk;
317
318	0	while(q->head && chunk_is_empty(q->head)) {
319	0	chunk = q->head;
320	0	q->head = chunk->next;
321	0	if(q->tail == chunk)
322	0	q->tail = q->head;
323	0	if(q->pool) {
324	0	bufcp_put(q->pool, chunk);
325	0	--q->chunk_count;
326	0	}
327	0	else if((q->chunk_count > q->max_chunks) \|\|
328	0	(q->opts & BUFQ_OPT_NO_SPARES)) {
329		/* SOFT_LIMIT allowed us more than max. free spares until
330		* we are at max again. Or free them if we are configured
331		* to not use spares. */
332	0	free(chunk);
333	0	--q->chunk_count;
334	0	}
335	0	else {
336	0	chunk->next = q->spare;
337	0	q->spare = chunk;
338	0	}
339	0	}
340	0	}
341
342		static struct buf_chunk get_non_full_tail(struct bufq q)
343	0	{
344	0	struct buf_chunk *chunk;
345
346	0	if(q->tail && !chunk_is_full(q->tail))
347	0	return q->tail;
348	0	chunk = get_spare(q);
349	0	if(chunk) {
350		/* new tail, and possibly new head */
351	0	if(q->tail) {
352	0	q->tail->next = chunk;
353	0	q->tail = chunk;
354	0	}
355	0	else {
356	0	DEBUGASSERT(!q->head);
357	0	q->head = q->tail = chunk;
358	0	}
359	0	}
360	0	return chunk;
361	0	}
362
363		CURLcode Curl_bufq_write(struct bufq *q,
364		const unsigned char *buf, size_t len,
365		size_t *pnwritten)
366	0	{
367	0	struct buf_chunk *tail;
368	0	size_t n;
369
370	0	DEBUGASSERT(q->max_chunks > 0);
371	0	*pnwritten = 0;
372	0	while(len) {
373	0	tail = get_non_full_tail(q);
374	0	if(!tail) {
375	0	if((q->chunk_count < q->max_chunks) \|\| (q->opts & BUFQ_OPT_SOFT_LIMIT))
376		/* should have gotten a tail, but did not */
377	0	return CURLE_OUT_OF_MEMORY;
378	0	break;
379	0	}
380	0	n = chunk_append(tail, buf, len);
381	0	if(!n)
382	0	break;
383	0	*pnwritten += n;
384	0	buf += n;
385	0	len -= n;
386	0	}
387	0	return (!*pnwritten && len) ? CURLE_AGAIN : CURLE_OK;
388	0	}
389
390		CURLcode Curl_bufq_cwrite(struct bufq *q,
391		const char *buf, size_t len,
392		size_t *pnwritten)
393	0	{
394	0	return Curl_bufq_write(q, (const unsigned char *)buf, len, pnwritten);
395	0	}
396
397		CURLcode Curl_bufq_read(struct bufq q, unsigned char buf, size_t len,
398		size_t *pnread)
399	0	{
400	0	*pnread = 0;
401	0	while(len && q->head) {
402	0	size_t n = chunk_read(q->head, buf, len);
403	0	if(n) {
404	0	*pnread += n;
405	0	buf += n;
406	0	len -= n;
407	0	}
408	0	prune_head(q);
409	0	}
410	0	return (!*pnread) ? CURLE_AGAIN : CURLE_OK;
411	0	}
412
413		CURLcode Curl_bufq_cread(struct bufq q, char buf, size_t len,
414		size_t *pnread)
415	0	{
416	0	return Curl_bufq_read(q, (unsigned char *)buf, len, pnread);
417	0	}
418
419		bool Curl_bufq_peek(struct bufq *q,
420		const unsigned char *pbuf, size_t plen)
421	0	{
422	0	if(q->head && chunk_is_empty(q->head)) {
423	0	prune_head(q);
424	0	}
425	0	if(q->head && !chunk_is_empty(q->head)) {
426	0	chunk_peek(q->head, pbuf, plen);
427	0	return TRUE;
428	0	}
429	0	*pbuf = NULL;
430	0	*plen = 0;
431	0	return FALSE;
432	0	}
433
434		bool Curl_bufq_peek_at(struct bufq *q, size_t offset,
435		const unsigned char *pbuf, size_t plen)
436	0	{
437	0	struct buf_chunk *c = q->head;
438	0	size_t clen;
439
440	0	while(c) {
441	0	clen = chunk_len(c);
442	0	if(!clen)
443	0	break;
444	0	if(offset >= clen) {
445	0	offset -= clen;
446	0	c = c->next;
447	0	continue;
448	0	}
449	0	chunk_peek_at(c, offset, pbuf, plen);
450	0	return TRUE;
451	0	}
452	0	*pbuf = NULL;
453	0	*plen = 0;
454	0	return FALSE;
455	0	}
456
457		void Curl_bufq_skip(struct bufq *q, size_t amount)
458	0	{
459	0	size_t n;
460
461	0	while(amount && q->head) {
462	0	n = chunk_skip(q->head, amount);
463	0	amount -= n;
464	0	prune_head(q);
465	0	}
466	0	}
467
468		CURLcode Curl_bufq_pass(struct bufq q, Curl_bufq_writer writer,
469		void writer_ctx, size_t pwritten)
470	0	{
471	0	const unsigned char *buf;
472	0	size_t blen;
473	0	CURLcode result = CURLE_OK;
474
475	0	*pwritten = 0;
476	0	while(Curl_bufq_peek(q, &buf, &blen)) {
477	0	size_t chunk_written;
478
479	0	result = writer(writer_ctx, buf, blen, &chunk_written);
480	0	if(result) {
481	0	if((result == CURLE_AGAIN) && *pwritten) {
482		/* blocked on subsequent write, report success */
483	0	result = CURLE_OK;
484	0	}
485	0	break;
486	0	}
487	0	if(!chunk_written) {
488	0	if(!*pwritten) {
489		/* treat as blocked */
490	0	result = CURLE_AGAIN;
491	0	}
492	0	break;
493	0	}
494	0	*pwritten += chunk_written;
495	0	Curl_bufq_skip(q, chunk_written);
496	0	}
497	0	return result;
498	0	}
499
500		CURLcode Curl_bufq_write_pass(struct bufq *q,
501		const unsigned char *buf, size_t len,
502		Curl_bufq_writer writer, void writer_ctx,
503		size_t *pwritten)
504	0	{
505	0	CURLcode result = CURLE_OK;
506	0	size_t n;
507
508	0	*pwritten = 0;
509	0	while(len) {
510	0	if(Curl_bufq_is_full(q)) {
511		/* try to make room in case we are full */
512	0	result = Curl_bufq_pass(q, writer, writer_ctx, &n);
513	0	if(result) {
514	0	if(result != CURLE_AGAIN) {
515		/* real error, fail */
516	0	return result;
517	0	}
518		/* would block, bufq is full, give up */
519	0	break;
520	0	}
521	0	}
522
523		/* Add to bufq as much as there is room for */
524	0	result = Curl_bufq_write(q, buf, len, &n);
525	0	if(result) {
526	0	if(result != CURLE_AGAIN)
527		/* real error, fail */
528	0	return result;
529	0	if((result == CURLE_AGAIN) && *pwritten)
530		/* we did write successfully before */
531	0	result = CURLE_OK;
532	0	return result;
533	0	}
534	0	else if(n == 0)
535		/* edge case of writer returning 0 (and len is >0)
536		* break or we might enter an infinite loop here */
537	0	break;
538
539		/* Track what we added to bufq */
540	0	buf += n;
541	0	len -= n;
542	0	*pwritten += n;
543	0	}
544
545	0	return (!*pwritten && len) ? CURLE_AGAIN : CURLE_OK;
546	0	}
547
548		CURLcode Curl_bufq_sipn(struct bufq *q, size_t max_len,
549		Curl_bufq_reader reader, void reader_ctx,
550		size_t *pnread)
551	0	{
552	0	struct buf_chunk *tail = NULL;
553
554	0	*pnread = 0;
555	0	tail = get_non_full_tail(q);
556	0	if(!tail) {
557	0	if(q->chunk_count < q->max_chunks)
558	0	return CURLE_OUT_OF_MEMORY;
559		/* full, blocked */
560	0	return CURLE_AGAIN;
561	0	}
562
563	0	return chunk_slurpn(tail, max_len, reader, reader_ctx, pnread);
564	0	}
565
566		/**
567		* Read up to `max_len` bytes and append it to the end of the buffer queue.
568		* if `max_len` is 0, no limit is imposed and the call behaves exactly
569		* the same as `Curl_bufq_slurp()`.
570		* Returns the total amount of buf read (may be 0) in `pnread` or error
571		* Note that even in case of an error chunks may have been read and
572		* the buffer queue will have different length than before.
573		*/
574		static CURLcode bufq_slurpn(struct bufq *q, size_t max_len,
575		Curl_bufq_reader reader, void reader_ctx,
576		size_t *pnread)
577	0	{
578	0	CURLcode result;
579
580	0	*pnread = 0;
581	0	while(1) {
582	0	size_t n;
583	0	result = Curl_bufq_sipn(q, max_len, reader, reader_ctx, &n);
584	0	if(result) {
585	0	if(!*pnread \|\| result != CURLE_AGAIN) {
586		/* blocked on first read or real error, fail */
587	0	return result;
588	0	}
589	0	result = CURLE_OK;
590	0	break;
591	0	}
592	0	else if(n == 0) {
593		/* eof */
594	0	result = CURLE_OK;
595	0	break;
596	0	}
597	0	*pnread += n;
598	0	if(max_len) {
599	0	DEBUGASSERT(n <= max_len);
600	0	max_len -= n;
601	0	if(!max_len)
602	0	break;
603	0	}
604		/* give up slurping when we get less bytes than we asked for */
605	0	if(q->tail && !chunk_is_full(q->tail))
606	0	break;
607	0	}
608	0	return result;
609	0	}
610
611		CURLcode Curl_bufq_slurp(struct bufq q, Curl_bufq_reader reader,
612		void reader_ctx, size_t pnread)
613	0	{
614	0	return bufq_slurpn(q, 0, reader, reader_ctx, pnread);
615	0	}