/src/curl/lib/bufq.c

Source
/***************************************************************************
 *                                  _   _ ____  _
 *  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"

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 uint8_t *buf, size_t len)
{
  uint8_t *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,
                         uint8_t *buf, size_t len)
{
  uint8_t *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)
{
  uint8_t *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 uint8_t **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 uint8_t **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;
    curlx_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;
  }

  /* Check for integer overflow before allocation */
  if(pool->chunk_size > SIZE_MAX - sizeof(*chunk)) {
    *pchunk = NULL;
    return CURLE_OUT_OF_MEMORY;
  }

  chunk = curlx_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) {
    curlx_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 {
    /* Check for integer overflow before allocation */
    if(q->chunk_size > SIZE_MAX - sizeof(*chunk)) {
      return NULL;
    }

    chunk = curlx_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. */
      curlx_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 uint8_t *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 uint8_t *)buf, len, pnwritten);
}

CURLcode Curl_bufq_read(struct bufq *q, uint8_t *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, (uint8_t *)buf, len, pnread);
}

bool Curl_bufq_peek(struct bufq *q,
                    const uint8_t **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 uint8_t **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 uint8_t *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 uint8_t *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;
      /* result == CURLE_AGAIN */
      if(*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 remains 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: 2025-12-14 06:23

Line	Count	Source
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		static bool chunk_is_empty(const struct buf_chunk *chunk)
29	0	{
30	0	return chunk->r_offset >= chunk->w_offset;
31	0	}
32
33		static bool chunk_is_full(const struct buf_chunk *chunk)
34	0	{
35	0	return chunk->w_offset >= chunk->dlen;
36	0	}
37
38		static size_t chunk_len(const struct buf_chunk *chunk)
39	0	{
40	0	return chunk->w_offset - chunk->r_offset;
41	0	}
42
43		static void chunk_reset(struct buf_chunk *chunk)
44	0	{
45	0	chunk->next = NULL;
46	0	chunk->r_offset = chunk->w_offset = 0;
47	0	}
48
49		static size_t chunk_append(struct buf_chunk *chunk,
50		const uint8_t *buf, size_t len)
51	0	{
52	0	uint8_t *p = &chunk->x.data[chunk->w_offset];
53	0	size_t n = chunk->dlen - chunk->w_offset;
54	0	DEBUGASSERT(chunk->dlen >= chunk->w_offset);
55	0	if(n) {
56	0	n = CURLMIN(n, len);
57	0	memcpy(p, buf, n);
58	0	chunk->w_offset += n;
59	0	}
60	0	return n;
61	0	}
62
63		static size_t chunk_read(struct buf_chunk *chunk,
64		uint8_t *buf, size_t len)
65	0	{
66	0	uint8_t *p = &chunk->x.data[chunk->r_offset];
67	0	size_t n = chunk->w_offset - chunk->r_offset;
68	0	DEBUGASSERT(chunk->w_offset >= chunk->r_offset);
69	0	if(!n) {
70	0	return 0;
71	0	}
72	0	else if(n <= len) {
73	0	memcpy(buf, p, n);
74	0	chunk->r_offset = chunk->w_offset = 0;
75	0	return n;
76	0	}
77	0	else {
78	0	memcpy(buf, p, len);
79	0	chunk->r_offset += len;
80	0	return len;
81	0	}
82	0	}
83
84		static CURLcode chunk_slurpn(struct buf_chunk *chunk, size_t max_len,
85		Curl_bufq_reader *reader,
86		void reader_ctx, size_t pnread)
87	0	{
88	0	uint8_t *p = &chunk->x.data[chunk->w_offset];
89	0	size_t n = chunk->dlen - chunk->w_offset; /* free amount */
90	0	CURLcode result;
91
92	0	*pnread = 0;
93	0	DEBUGASSERT(chunk->dlen >= chunk->w_offset);
94	0	if(!n)
95	0	return CURLE_AGAIN;
96	0	if(max_len && n > max_len)
97	0	n = max_len;
98	0	result = reader(reader_ctx, p, n, pnread);
99	0	if(!result) {
100	0	DEBUGASSERT(*pnread <= n);
101	0	chunk->w_offset += *pnread;
102	0	}
103	0	return result;
104	0	}
105
106		static void chunk_peek(const struct buf_chunk *chunk,
107		const uint8_t *pbuf, size_t plen)
108	0	{
109	0	DEBUGASSERT(chunk->w_offset >= chunk->r_offset);
110	0	*pbuf = &chunk->x.data[chunk->r_offset];
111	0	*plen = chunk->w_offset - chunk->r_offset;
112	0	}
113
114		static void chunk_peek_at(const struct buf_chunk *chunk, size_t offset,
115		const uint8_t *pbuf, size_t plen)
116	0	{
117	0	offset += chunk->r_offset;
118	0	DEBUGASSERT(chunk->w_offset >= offset);
119	0	*pbuf = &chunk->x.data[offset];
120	0	*plen = chunk->w_offset - offset;
121	0	}
122
123		static size_t chunk_skip(struct buf_chunk *chunk, size_t amount)
124	0	{
125	0	size_t n = chunk->w_offset - chunk->r_offset;
126	0	DEBUGASSERT(chunk->w_offset >= chunk->r_offset);
127	0	if(n) {
128	0	n = CURLMIN(n, amount);
129	0	chunk->r_offset += n;
130	0	if(chunk->r_offset == chunk->w_offset)
131	0	chunk->r_offset = chunk->w_offset = 0;
132	0	}
133	0	return n;
134	0	}
135
136		static void chunk_list_free(struct buf_chunk **anchor)
137	0	{
138	0	struct buf_chunk *chunk;
139	0	while(*anchor) {
140	0	chunk = *anchor;
141	0	*anchor = chunk->next;
142	0	curlx_free(chunk);
143	0	}
144	0	}
145
146		void Curl_bufcp_init(struct bufc_pool *pool,
147		size_t chunk_size, size_t spare_max)
148	0	{
149	0	DEBUGASSERT(chunk_size > 0);
150	0	DEBUGASSERT(spare_max > 0);
151	0	memset(pool, 0, sizeof(*pool));
152	0	pool->chunk_size = chunk_size;
153	0	pool->spare_max = spare_max;
154	0	}
155
156		static CURLcode bufcp_take(struct bufc_pool *pool,
157		struct buf_chunk **pchunk)
158	0	{
159	0	struct buf_chunk *chunk = NULL;
160
161	0	if(pool->spare) {
162	0	chunk = pool->spare;
163	0	pool->spare = chunk->next;
164	0	--pool->spare_count;
165	0	chunk_reset(chunk);
166	0	*pchunk = chunk;
167	0	return CURLE_OK;
168	0	}
169
170		/* Check for integer overflow before allocation */
171	0	if(pool->chunk_size > SIZE_MAX - sizeof(*chunk)) {
172	0	*pchunk = NULL;
173	0	return CURLE_OUT_OF_MEMORY;
174	0	}
175
176	0	chunk = curlx_calloc(1, sizeof(*chunk) + pool->chunk_size);
177	0	if(!chunk) {
178	0	*pchunk = NULL;
179	0	return CURLE_OUT_OF_MEMORY;
180	0	}
181	0	chunk->dlen = pool->chunk_size;
182	0	*pchunk = chunk;
183	0	return CURLE_OK;
184	0	}
185
186		static void bufcp_put(struct bufc_pool *pool,
187		struct buf_chunk *chunk)
188	0	{
189	0	if(pool->spare_count >= pool->spare_max) {
190	0	curlx_free(chunk);
191	0	}
192	0	else {
193	0	chunk_reset(chunk);
194	0	chunk->next = pool->spare;
195	0	pool->spare = chunk;
196	0	++pool->spare_count;
197	0	}
198	0	}
199
200		void Curl_bufcp_free(struct bufc_pool *pool)
201	0	{
202	0	chunk_list_free(&pool->spare);
203	0	pool->spare_count = 0;
204	0	}
205
206		static void bufq_init(struct bufq q, struct bufc_pool pool,
207		size_t chunk_size, size_t max_chunks, int opts)
208	0	{
209	0	DEBUGASSERT(chunk_size > 0);
210	0	DEBUGASSERT(max_chunks > 0);
211	0	memset(q, 0, sizeof(*q));
212	0	q->chunk_size = chunk_size;
213	0	q->max_chunks = max_chunks;
214	0	q->pool = pool;
215	0	q->opts = opts;
216	0	}
217
218		void Curl_bufq_init2(struct bufq *q, size_t chunk_size, size_t max_chunks,
219		int opts)
220	0	{
221	0	bufq_init(q, NULL, chunk_size, max_chunks, opts);
222	0	}
223
224		void Curl_bufq_init(struct bufq *q, size_t chunk_size, size_t max_chunks)
225	0	{
226	0	bufq_init(q, NULL, chunk_size, max_chunks, BUFQ_OPT_NONE);
227	0	}
228
229		void Curl_bufq_initp(struct bufq q, struct bufc_pool pool,
230		size_t max_chunks, int opts)
231	0	{
232	0	bufq_init(q, pool, pool->chunk_size, max_chunks, opts);
233	0	}
234
235		void Curl_bufq_free(struct bufq *q)
236	0	{
237	0	chunk_list_free(&q->head);
238	0	chunk_list_free(&q->spare);
239	0	q->tail = NULL;
240	0	q->chunk_count = 0;
241	0	}
242
243		void Curl_bufq_reset(struct bufq *q)
244	0	{
245	0	struct buf_chunk *chunk;
246	0	while(q->head) {
247	0	chunk = q->head;
248	0	q->head = chunk->next;
249	0	chunk->next = q->spare;
250	0	q->spare = chunk;
251	0	}
252	0	q->tail = NULL;
253	0	}
254
255		size_t Curl_bufq_len(const struct bufq *q)
256	0	{
257	0	const struct buf_chunk *chunk = q->head;
258	0	size_t len = 0;
259	0	while(chunk) {
260	0	len += chunk_len(chunk);
261	0	chunk = chunk->next;
262	0	}
263	0	return len;
264	0	}
265
266		bool Curl_bufq_is_empty(const struct bufq *q)
267	0	{
268	0	return !q->head \|\| chunk_is_empty(q->head);
269	0	}
270
271		bool Curl_bufq_is_full(const struct bufq *q)
272	0	{
273	0	if(!q->tail \|\| q->spare)
274	0	return FALSE;
275	0	if(q->chunk_count < q->max_chunks)
276	0	return FALSE;
277	0	if(q->chunk_count > q->max_chunks)
278	0	return TRUE;
279		/* we have no spares and cannot make more, is the tail full? */
280	0	return chunk_is_full(q->tail);
281	0	}
282
283		static struct buf_chunk get_spare(struct bufq q)
284	0	{
285	0	struct buf_chunk *chunk = NULL;
286
287	0	if(q->spare) {
288	0	chunk = q->spare;
289	0	q->spare = chunk->next;
290	0	chunk_reset(chunk);
291	0	return chunk;
292	0	}
293
294	0	if(q->chunk_count >= q->max_chunks && (!(q->opts & BUFQ_OPT_SOFT_LIMIT)))
295	0	return NULL;
296
297	0	if(q->pool) {
298	0	if(bufcp_take(q->pool, &chunk))
299	0	return NULL;
300	0	++q->chunk_count;
301	0	return chunk;
302	0	}
303	0	else {
304		/* Check for integer overflow before allocation */
305	0	if(q->chunk_size > SIZE_MAX - sizeof(*chunk)) {
306	0	return NULL;
307	0	}
308
309	0	chunk = curlx_calloc(1, sizeof(*chunk) + q->chunk_size);
310	0	if(!chunk)
311	0	return NULL;
312	0	chunk->dlen = q->chunk_size;
313	0	++q->chunk_count;
314	0	return chunk;
315	0	}
316	0	}
317
318		static void prune_head(struct bufq *q)
319	0	{
320	0	struct buf_chunk *chunk;
321
322	0	while(q->head && chunk_is_empty(q->head)) {
323	0	chunk = q->head;
324	0	q->head = chunk->next;
325	0	if(q->tail == chunk)
326	0	q->tail = q->head;
327	0	if(q->pool) {
328	0	bufcp_put(q->pool, chunk);
329	0	--q->chunk_count;
330	0	}
331	0	else if((q->chunk_count > q->max_chunks) \|\|
332	0	(q->opts & BUFQ_OPT_NO_SPARES)) {
333		/* SOFT_LIMIT allowed us more than max. free spares until
334		* we are at max again. Or free them if we are configured
335		* to not use spares. */
336	0	curlx_free(chunk);
337	0	--q->chunk_count;
338	0	}
339	0	else {
340	0	chunk->next = q->spare;
341	0	q->spare = chunk;
342	0	}
343	0	}
344	0	}
345
346		static struct buf_chunk get_non_full_tail(struct bufq q)
347	0	{
348	0	struct buf_chunk *chunk;
349
350	0	if(q->tail && !chunk_is_full(q->tail))
351	0	return q->tail;
352	0	chunk = get_spare(q);
353	0	if(chunk) {
354		/* new tail, and possibly new head */
355	0	if(q->tail) {
356	0	q->tail->next = chunk;
357	0	q->tail = chunk;
358	0	}
359	0	else {
360	0	DEBUGASSERT(!q->head);
361	0	q->head = q->tail = chunk;
362	0	}
363	0	}
364	0	return chunk;
365	0	}
366
367		CURLcode Curl_bufq_write(struct bufq *q,
368		const uint8_t *buf, size_t len,
369		size_t *pnwritten)
370	0	{
371	0	struct buf_chunk *tail;
372	0	size_t n;
373
374	0	DEBUGASSERT(q->max_chunks > 0);
375	0	*pnwritten = 0;
376	0	while(len) {
377	0	tail = get_non_full_tail(q);
378	0	if(!tail) {
379	0	if((q->chunk_count < q->max_chunks) \|\| (q->opts & BUFQ_OPT_SOFT_LIMIT))
380		/* should have gotten a tail, but did not */
381	0	return CURLE_OUT_OF_MEMORY;
382	0	break;
383	0	}
384	0	n = chunk_append(tail, buf, len);
385	0	if(!n)
386	0	break;
387	0	*pnwritten += n;
388	0	buf += n;
389	0	len -= n;
390	0	}
391	0	return (!*pnwritten && len) ? CURLE_AGAIN : CURLE_OK;
392	0	}
393
394		CURLcode Curl_bufq_cwrite(struct bufq *q,
395		const char *buf, size_t len,
396		size_t *pnwritten)
397	0	{
398	0	return Curl_bufq_write(q, (const uint8_t *)buf, len, pnwritten);
399	0	}
400
401		CURLcode Curl_bufq_read(struct bufq q, uint8_t buf, size_t len,
402		size_t *pnread)
403	0	{
404	0	*pnread = 0;
405	0	while(len && q->head) {
406	0	size_t n = chunk_read(q->head, buf, len);
407	0	if(n) {
408	0	*pnread += n;
409	0	buf += n;
410	0	len -= n;
411	0	}
412	0	prune_head(q);
413	0	}
414	0	return (!*pnread) ? CURLE_AGAIN : CURLE_OK;
415	0	}
416
417		CURLcode Curl_bufq_cread(struct bufq q, char buf, size_t len,
418		size_t *pnread)
419	0	{
420	0	return Curl_bufq_read(q, (uint8_t *)buf, len, pnread);
421	0	}
422
423		bool Curl_bufq_peek(struct bufq *q,
424		const uint8_t *pbuf, size_t plen)
425	0	{
426	0	if(q->head && chunk_is_empty(q->head)) {
427	0	prune_head(q);
428	0	}
429	0	if(q->head && !chunk_is_empty(q->head)) {
430	0	chunk_peek(q->head, pbuf, plen);
431	0	return TRUE;
432	0	}
433	0	*pbuf = NULL;
434	0	*plen = 0;
435	0	return FALSE;
436	0	}
437
438		bool Curl_bufq_peek_at(struct bufq *q, size_t offset,
439		const uint8_t *pbuf, size_t plen)
440	0	{
441	0	struct buf_chunk *c = q->head;
442	0	size_t clen;
443
444	0	while(c) {
445	0	clen = chunk_len(c);
446	0	if(!clen)
447	0	break;
448	0	if(offset >= clen) {
449	0	offset -= clen;
450	0	c = c->next;
451	0	continue;
452	0	}
453	0	chunk_peek_at(c, offset, pbuf, plen);
454	0	return TRUE;
455	0	}
456	0	*pbuf = NULL;
457	0	*plen = 0;
458	0	return FALSE;
459	0	}
460
461		void Curl_bufq_skip(struct bufq *q, size_t amount)
462	0	{
463	0	size_t n;
464
465	0	while(amount && q->head) {
466	0	n = chunk_skip(q->head, amount);
467	0	amount -= n;
468	0	prune_head(q);
469	0	}
470	0	}
471
472		CURLcode Curl_bufq_pass(struct bufq q, Curl_bufq_writer writer,
473		void writer_ctx, size_t pwritten)
474	0	{
475	0	const uint8_t *buf;
476	0	size_t blen;
477	0	CURLcode result = CURLE_OK;
478
479	0	*pwritten = 0;
480	0	while(Curl_bufq_peek(q, &buf, &blen)) {
481	0	size_t chunk_written;
482
483	0	result = writer(writer_ctx, buf, blen, &chunk_written);
484	0	if(result) {
485	0	if((result == CURLE_AGAIN) && *pwritten) {
486		/* blocked on subsequent write, report success */
487	0	result = CURLE_OK;
488	0	}
489	0	break;
490	0	}
491	0	if(!chunk_written) {
492	0	if(!*pwritten) {
493		/* treat as blocked */
494	0	result = CURLE_AGAIN;
495	0	}
496	0	break;
497	0	}
498	0	*pwritten += chunk_written;
499	0	Curl_bufq_skip(q, chunk_written);
500	0	}
501	0	return result;
502	0	}
503
504		CURLcode Curl_bufq_write_pass(struct bufq *q,
505		const uint8_t *buf, size_t len,
506		Curl_bufq_writer writer, void writer_ctx,
507		size_t *pwritten)
508	0	{
509	0	CURLcode result = CURLE_OK;
510	0	size_t n;
511
512	0	*pwritten = 0;
513	0	while(len) {
514	0	if(Curl_bufq_is_full(q)) {
515		/* try to make room in case we are full */
516	0	result = Curl_bufq_pass(q, writer, writer_ctx, &n);
517	0	if(result) {
518	0	if(result != CURLE_AGAIN) {
519		/* real error, fail */
520	0	return result;
521	0	}
522		/* would block, bufq is full, give up */
523	0	break;
524	0	}
525	0	}
526
527		/* Add to bufq as much as there is room for */
528	0	result = Curl_bufq_write(q, buf, len, &n);
529	0	if(result) {
530	0	if(result != CURLE_AGAIN)
531		/* real error, fail */
532	0	return result;
533		/* result == CURLE_AGAIN */
534	0	if(*pwritten)
535		/* we did write successfully before */
536	0	result = CURLE_OK;
537	0	return result;
538	0	}
539	0	else if(n == 0)
540		/* edge case of writer returning 0 (and len is >0)
541		* break or we might enter an infinite loop here */
542	0	break;
543
544		/* Track what we added to bufq */
545	0	buf += n;
546	0	len -= n;
547	0	*pwritten += n;
548	0	}
549
550	0	return (!*pwritten && len) ? CURLE_AGAIN : CURLE_OK;
551	0	}
552
553		CURLcode Curl_bufq_sipn(struct bufq *q, size_t max_len,
554		Curl_bufq_reader reader, void reader_ctx,
555		size_t *pnread)
556	0	{
557	0	struct buf_chunk *tail = NULL;
558
559	0	*pnread = 0;
560	0	tail = get_non_full_tail(q);
561	0	if(!tail) {
562	0	if(q->chunk_count < q->max_chunks)
563	0	return CURLE_OUT_OF_MEMORY;
564		/* full, blocked */
565	0	return CURLE_AGAIN;
566	0	}
567
568	0	return chunk_slurpn(tail, max_len, reader, reader_ctx, pnread);
569	0	}
570
571		/**
572		* Read up to `max_len` bytes and append it to the end of the buffer queue.
573		* if `max_len` is 0, no limit is imposed and the call behaves exactly
574		* the same as `Curl_bufq_slurp()`.
575		* Returns the total amount of buf read (may be 0) in `pnread` or error
576		* Note that even in case of an error chunks may have been read and
577		* the buffer queue will have different length than before.
578		*/
579		static CURLcode bufq_slurpn(struct bufq *q, size_t max_len,
580		Curl_bufq_reader reader, void reader_ctx,
581		size_t *pnread)
582	0	{
583	0	CURLcode result;
584
585	0	*pnread = 0;
586	0	while(1) {
587	0	size_t n;
588	0	result = Curl_bufq_sipn(q, max_len, reader, reader_ctx, &n);
589	0	if(result) {
590	0	if(!*pnread \|\| result != CURLE_AGAIN) {
591		/* blocked on first read or real error, fail */
592	0	return result;
593	0	}
594	0	result = CURLE_OK;
595	0	break;
596	0	}
597	0	else if(n == 0) {
598		/* eof, result remains CURLE_OK */
599	0	break;
600	0	}
601	0	*pnread += n;
602	0	if(max_len) {
603	0	DEBUGASSERT(n <= max_len);
604	0	max_len -= n;
605	0	if(!max_len)
606	0	break;
607	0	}
608		/* give up slurping when we get less bytes than we asked for */
609	0	if(q->tail && !chunk_is_full(q->tail))
610	0	break;
611	0	}
612	0	return result;
613	0	}
614
615		CURLcode Curl_bufq_slurp(struct bufq q, Curl_bufq_reader reader,
616		void reader_ctx, size_t pnread)
617	0	{
618	0	return bufq_slurpn(q, 0, reader, reader_ctx, pnread);
619	0	}