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authorAlexSm <alex@ydb.tech>2024-01-18 11:28:56 +0100
committerGitHub <noreply@github.com>2024-01-18 11:28:56 +0100
commit9d0a3761b3201e0d9db879a7adf91876ebdb0564 (patch)
tree541d11ac878c18efd7ebca81e35112aa0fef995b /contrib/libs/curl/lib/bufq.h
parent404ef8886ecc9736bc58ade6da2fbd83b486a408 (diff)
downloadydb-9d0a3761b3201e0d9db879a7adf91876ebdb0564.tar.gz
Library import 8 (#1074)
* Library import 8 * Add contrib/libs/cxxsupp/libcxx/include/__verbose_abort
Diffstat (limited to 'contrib/libs/curl/lib/bufq.h')
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1 files changed, 265 insertions, 0 deletions
diff --git a/contrib/libs/curl/lib/bufq.h b/contrib/libs/curl/lib/bufq.h
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+#ifndef HEADER_CURL_BUFQ_H
+#define HEADER_CURL_BUFQ_H
+/***************************************************************************
+ * _ _ ____ _
+ * 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 <curl/curl.h>
+
+/**
+ * A chunk of bytes for reading and writing.
+ * The size is fixed a creation with read and write offset
+ * for where unread content is.
+ */
+struct buf_chunk {
+ struct buf_chunk *next; /* to keep it in a list */
+ size_t dlen; /* the amount of allocated x.data[] */
+ size_t r_offset; /* first unread bytes */
+ size_t w_offset; /* one after last written byte */
+ union {
+ unsigned char data[1]; /* the buffer for `dlen` bytes */
+ void *dummy; /* alignment */
+ } x;
+};
+
+/**
+ * A pool for providing/keeping a number of chunks of the same size
+ *
+ * The same pool can be shared by many `bufq` instances. However, a pool
+ * is not thread safe. All bufqs using it are supposed to operate in the
+ * same thread.
+ */
+struct bufc_pool {
+ struct buf_chunk *spare; /* list of available spare chunks */
+ size_t chunk_size; /* the size of chunks in this pool */
+ size_t spare_count; /* current number of spare chunks in list */
+ size_t spare_max; /* max number of spares to keep */
+};
+
+void Curl_bufcp_init(struct bufc_pool *pool,
+ size_t chunk_size, size_t spare_max);
+
+void Curl_bufcp_free(struct bufc_pool *pool);
+
+/**
+ * A queue of byte chunks for reading and writing.
+ * Reading is done from `head`, writing is done to `tail`.
+ *
+ * `bufq`s can be empty or full or neither. Its `len` is the number
+ * of bytes that can be read. For an empty bufq, `len` will be 0.
+ *
+ * By default, a bufq can hold up to `max_chunks * chunk_size` number
+ * of bytes. When `max_chunks` are used (in the `head` list) and the
+ * `tail` chunk is full, the bufq will report that it is full.
+ *
+ * On a full bufq, `len` may be less than the maximum number of bytes,
+ * e.g. when the head chunk is partially read. `len` may also become
+ * larger than the max when option `BUFQ_OPT_SOFT_LIMIT` is used.
+ *
+ * By default, writing to a full bufq will return (-1, CURLE_AGAIN). Same
+ * as reading from an empty bufq.
+ * With `BUFQ_OPT_SOFT_LIMIT` set, a bufq will allow writing becond this
+ * limit and use more than `max_chunks`. However it will report that it
+ * is full nevertheless. This is provided for situation where writes
+ * preferably never fail (except for memory exhaustion).
+ *
+ * By default and without a pool, a bufq will keep chunks that read
+ * read empty in its `spare` list. Option `BUFQ_OPT_NO_SPARES` will
+ * disable that and free chunks once they become empty.
+ *
+ * When providing a pool to a bufq, all chunk creation and spare handling
+ * will be delegated to that pool.
+ */
+struct bufq {
+ struct buf_chunk *head; /* chunk with bytes to read from */
+ struct buf_chunk *tail; /* chunk to write to */
+ struct buf_chunk *spare; /* list of free chunks, unless `pool` */
+ struct bufc_pool *pool; /* optional pool for free chunks */
+ size_t chunk_count; /* current number of chunks in `head+spare` */
+ size_t max_chunks; /* max `head` chunks to use */
+ size_t chunk_size; /* size of chunks to manage */
+ int opts; /* options for handling queue, see below */
+};
+
+/**
+ * Default behaviour: chunk limit is "hard", meaning attempts to write
+ * more bytes than can be hold in `max_chunks` is refused and will return
+ * -1, CURLE_AGAIN. */
+#define BUFQ_OPT_NONE (0)
+/**
+ * Make `max_chunks` a "soft" limit. A bufq will report that it is "full"
+ * when `max_chunks` are used, but allows writing beyond this limit.
+ */
+#define BUFQ_OPT_SOFT_LIMIT (1 << 0)
+/**
+ * Do not keep spare chunks.
+ */
+#define BUFQ_OPT_NO_SPARES (1 << 1)
+
+/**
+ * Initialize a buffer queue that can hold up to `max_chunks` buffers
+ * each of size `chunk_size`. The bufq will not allow writing of
+ * more bytes than can be held in `max_chunks`.
+ */
+void Curl_bufq_init(struct bufq *q, size_t chunk_size, size_t max_chunks);
+
+/**
+ * Initialize a buffer queue that can hold up to `max_chunks` buffers
+ * each of size `chunk_size` with the given options. See `BUFQ_OPT_*`.
+ */
+void Curl_bufq_init2(struct bufq *q, size_t chunk_size,
+ size_t max_chunks, int opts);
+
+void Curl_bufq_initp(struct bufq *q, struct bufc_pool *pool,
+ size_t max_chunks, int opts);
+
+/**
+ * Reset the buffer queue to be empty. Will keep any allocated buffer
+ * chunks around.
+ */
+void Curl_bufq_reset(struct bufq *q);
+
+/**
+ * Free all resources held by the buffer queue.
+ */
+void Curl_bufq_free(struct bufq *q);
+
+/**
+ * Return the total amount of data in the queue.
+ */
+size_t Curl_bufq_len(const struct bufq *q);
+
+/**
+ * Return the total amount of free space in the queue.
+ * The returned length is the number of bytes that can
+ * be expected to be written successfully to the bufq,
+ * providing no memory allocations fail.
+ */
+size_t Curl_bufq_space(const struct bufq *q);
+
+/**
+ * Returns TRUE iff there is no data in the buffer queue.
+ */
+bool Curl_bufq_is_empty(const struct bufq *q);
+
+/**
+ * Returns TRUE iff there is no space left in the buffer queue.
+ */
+bool Curl_bufq_is_full(const struct bufq *q);
+
+/**
+ * Write buf to the end of the buffer queue. The buf is copied
+ * and the amount of copied bytes is returned.
+ * A return code of -1 indicates an error, setting `err` to the
+ * cause. An err of CURLE_AGAIN is returned if the buffer queue is full.
+ */
+ssize_t Curl_bufq_write(struct bufq *q,
+ const unsigned char *buf, size_t len,
+ CURLcode *err);
+
+/**
+ * Read buf from the start of the buffer queue. The buf is copied
+ * and the amount of copied bytes is returned.
+ * A return code of -1 indicates an error, setting `err` to the
+ * cause. An err of CURLE_AGAIN is returned if the buffer queue is empty.
+ */
+ssize_t Curl_bufq_read(struct bufq *q, unsigned char *buf, size_t len,
+ CURLcode *err);
+
+/**
+ * Peek at the head chunk in the buffer queue. Returns a pointer to
+ * the chunk buf (at the current offset) and its length. Does not
+ * modify the buffer queue.
+ * Returns TRUE iff bytes are available. Sets `pbuf` to NULL and `plen`
+ * to 0 when no bytes are available.
+ * Repeated calls return the same information until the buffer queue
+ * is modified, see `Curl_bufq_skip()``
+ */
+bool Curl_bufq_peek(struct bufq *q,
+ const unsigned char **pbuf, size_t *plen);
+
+bool Curl_bufq_peek_at(struct bufq *q, size_t offset,
+ const unsigned char **pbuf, size_t *plen);
+
+/**
+ * Tell the buffer queue to discard `amount` buf bytes at the head
+ * of the queue. Skipping more buf than is currently buffered will
+ * just empty the queue.
+ */
+void Curl_bufq_skip(struct bufq *q, size_t amount);
+
+typedef ssize_t Curl_bufq_writer(void *writer_ctx,
+ const unsigned char *buf, size_t len,
+ CURLcode *err);
+/**
+ * Passes the chunks in the buffer queue to the writer and returns
+ * the amount of buf written. A writer may return -1 and CURLE_AGAIN
+ * to indicate blocking at which point the queue will stop and return
+ * the amount of buf passed so far.
+ * -1 is returned on any other errors reported by the writer.
+ * Note that in case of a -1 chunks may have been written and
+ * the buffer queue will have different length than before.
+ */
+ssize_t Curl_bufq_pass(struct bufq *q, Curl_bufq_writer *writer,
+ void *writer_ctx, CURLcode *err);
+
+typedef ssize_t Curl_bufq_reader(void *reader_ctx,
+ unsigned char *buf, size_t len,
+ CURLcode *err);
+
+/**
+ * Read date and append it to the end of the buffer queue until the
+ * reader returns blocking or the queue is full. A reader returns
+ * -1 and CURLE_AGAIN to indicate blocking.
+ * Returns the total amount of buf read (may be 0) or -1 on other
+ * reader errors.
+ * Note that in case of a -1 chunks may have been read and
+ * the buffer queue will have different length than before.
+ */
+ssize_t Curl_bufq_slurp(struct bufq *q, Curl_bufq_reader *reader,
+ void *reader_ctx, CURLcode *err);
+
+/**
+ * Read *once* up to `max_len` bytes and append it to the buffer.
+ * if `max_len` is 0, no limit is imposed besides the chunk space.
+ * Returns the total amount of buf read (may be 0) or -1 on other
+ * reader errors.
+ */
+ssize_t Curl_bufq_sipn(struct bufq *q, size_t max_len,
+ Curl_bufq_reader *reader, void *reader_ctx,
+ CURLcode *err);
+
+/**
+ * Write buf to the end of the buffer queue.
+ * Will write bufq content or passed `buf` directly using the `writer`
+ * callback when it sees fit. 'buf' might get passed directly
+ * on or is placed into the buffer, depending on `len` and current
+ * amount buffered, chunk size, etc.
+ */
+ssize_t Curl_bufq_write_pass(struct bufq *q,
+ const unsigned char *buf, size_t len,
+ Curl_bufq_writer *writer, void *writer_ctx,
+ CURLcode *err);
+
+#endif /* HEADER_CURL_BUFQ_H */