curl/lib/transfer.h
Stefan Eissing 3755153571
lib: Curl_read/Curl_write clarifications
- replace `Curl_read()`, `Curl_write()` and `Curl_nwrite()` to
  clarify when and at what level they operate
- send/recv of transfer related data is now done via
  `Curl_xfer_send()/Curl_xfer_recv()` which no longer has
  socket/socketindex as parameter. It decides on the transfer
  setup of `conn->sockfd` and `conn->writesockfd` on which
  connection filter chain to operate.
- send/recv on a specific connection filter chain is done via
  `Curl_conn_send()/Curl_conn_recv()` which get the socket index
  as parameter.
- rename `Curl_setup_transfer()` to `Curl_xfer_setup()` for
  naming consistency
- clarify that the special CURLE_AGAIN hangling to return
  `CURLE_OK` with length 0 only applies to `Curl_xfer_send()`
  and CURLE_AGAIN is returned by all other send() variants.
- fix a bug in websocket `curl_ws_recv()` that mixed up data
  when it arrived in more than a single chunk

The method for sending not just raw bytes, but bytes that are either
"headers" or "body". The send abstraction stack, to to bottom, now is:

* `Curl_req_send()`: has parameter to indicate amount of header bytes,
  buffers all data.
* `Curl_xfer_send()`: knows on which socket index to send, returns
  amount of bytes sent.
* `Curl_conn_send()`: called with socket index, returns amount of bytes
  sent.

In addition there is `Curl_req_flush()` for writing out all buffered
bytes.

`Curl_req_send()` is active for requests without body,
`Curl_buffer_send()` still being used for others. This is because the
special quirks need to be addressed in future parts:

* `expect-100` handling
* `Curl_fillreadbuffer()` needs to add directly to the new
  `data->req.sendbuf`
* special body handlings, like `chunked` encodings and line end
  conversions will be moved into something like a Client Reader.

In functions of the pattern `CURLcode xxx_send(..., ssize_t *written)`,
replace the `ssize_t` with a `size_t`. It makes no sense to allow for negative
values as the returned `CURLcode` already specifies error conditions. This
allows easier handling of lengths without casting.

Closes #12964
2024-02-27 14:13:56 +01:00

112 lines
4.6 KiB
C

#ifndef HEADER_CURL_TRANSFER_H
#define HEADER_CURL_TRANSFER_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
*
***************************************************************************/
#define Curl_headersep(x) ((((x)==':') || ((x)==';')))
char *Curl_checkheaders(const struct Curl_easy *data,
const char *thisheader,
const size_t thislen);
void Curl_init_CONNECT(struct Curl_easy *data);
CURLcode Curl_pretransfer(struct Curl_easy *data);
CURLcode Curl_posttransfer(struct Curl_easy *data);
typedef enum {
FOLLOW_NONE, /* not used within the function, just a placeholder to
allow initing to this */
FOLLOW_FAKE, /* only records stuff, not actually following */
FOLLOW_RETRY, /* set if this is a request retry as opposed to a real
redirect following */
FOLLOW_REDIR /* a full true redirect */
} followtype;
CURLcode Curl_follow(struct Curl_easy *data, char *newurl,
followtype type);
CURLcode Curl_readwrite(struct Curl_easy *data, bool *done);
int Curl_single_getsock(struct Curl_easy *data,
struct connectdata *conn, curl_socket_t *socks);
CURLcode Curl_fillreadbuffer(struct Curl_easy *data, size_t bytes,
size_t *nreadp);
CURLcode Curl_retry_request(struct Curl_easy *data, char **url);
bool Curl_meets_timecondition(struct Curl_easy *data, time_t timeofdoc);
CURLcode Curl_get_upload_buffer(struct Curl_easy *data);
CURLcode Curl_done_sending(struct Curl_easy *data,
struct SingleRequest *k);
/**
* Write the transfer raw response bytes, as received from the connection.
* Will handle all passed bytes or return an error. By default, this will
* write the bytes as BODY to the client. Protocols may provide a
* "write_resp" callback in their handler to add specific treatment. E.g.
* HTTP parses response headers and passes them differently to the client.
* @param data the transfer
* @param buf the raw response bytes
* @param blen the amount of bytes in `buf`
* @param is_eos TRUE iff the connection indicates this to be the last
* bytes of the response
* @param done on returnm, TRUE iff the response is complete
*/
CURLcode Curl_xfer_write_resp(struct Curl_easy *data,
char *buf, size_t blen,
bool is_eos, bool *done);
/* This sets up a forthcoming transfer */
void Curl_xfer_setup(struct Curl_easy *data,
int sockindex, /* socket index to read from or -1 */
curl_off_t size, /* -1 if unknown at this point */
bool getheader, /* TRUE if header parsing is wanted */
int writesockindex /* socket index to write to. May be
the same we read from. -1
disables */
);
/**
* Multi has set transfer to DONE. Last chance to trigger
* missing response things like writing an EOS to the client.
*/
CURLcode Curl_xfer_write_done(struct Curl_easy *data, bool premature);
/**
* Send data on the socket/connection filter designated
* for transfer's outgoing data.
* Will return CURLE_OK on blocking with (*pnwritten == 0).
*/
CURLcode Curl_xfer_send(struct Curl_easy *data,
const void *buf, size_t blen,
size_t *pnwritten);
/**
* Receive data on the socket/connection filter designated
* for transfer's incoming data.
* Will return CURLE_AGAIN on blocking with (*pnrcvd == 0).
*/
CURLcode Curl_xfer_recv(struct Curl_easy *data,
char *buf, size_t blen,
ssize_t *pnrcvd);
#endif /* HEADER_CURL_TRANSFER_H */