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eed3c8f4b7
curl/lib/cfilters.h
Stefan Eissing ea6f5c9f0f
connect: limit update IP info 
Update IP related information at the connection and the transfer in two
places only: once the filter chain connects and when a transfer is added
to a connection. The latter only updates on reuse when the filters
already are connected.

The only user of that information before a full connect is the HAProxy
filter. Add cfilter CF_QUERY_IP_INFO query to let it find the
information from the filters "below".

This solves two issues with the previous version:
- updates where often done twice with the same info
- happy eyeballing filter "forks" could overwrite each others
  updates before the full winner was determined.

Closes #14699
2024-08-28 13:58:10 +02:00

697 lines
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#ifndef HEADER_CURL_CFILTERS_H
#define HEADER_CURL_CFILTERS_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 "timediff.h"
struct Curl_cfilter;
struct Curl_easy;
struct Curl_dns_entry;
struct connectdata;
struct ip_quadruple;
/* Callback to destroy resources held by this filter instance.
* Implementations MUST NOT chain calls to cf->next.
*/
typedef void Curl_cft_destroy_this(struct Curl_cfilter *cf,
struct Curl_easy *data);
/* Callback to close the connection immediately. */
typedef void Curl_cft_close(struct Curl_cfilter *cf,
struct Curl_easy *data);
/* Callback to close the connection filter gracefully, non-blocking.
* Implementations MUST NOT chain calls to cf->next.
*/
typedef CURLcode Curl_cft_shutdown(struct Curl_cfilter *cf,
struct Curl_easy *data,
bool *done);
typedef CURLcode Curl_cft_connect(struct Curl_cfilter *cf,
struct Curl_easy *data,
bool blocking, bool *done);
/* Return the hostname and port the connection goes to.
* This may change with the connection state of filters when tunneling
* is involved.
* @param cf the filter to ask
* @param data the easy handle currently active
* @param phost on return, points to the relevant, real hostname.
* this is owned by the connection.
* @param pdisplay_host on return, points to the printable hostname.
* this is owned by the connection.
* @param pport on return, contains the port number
*/
typedef void Curl_cft_get_host(struct Curl_cfilter *cf,
struct Curl_easy *data,
const char **phost,
const char **pdisplay_host,
int *pport);
struct easy_pollset;
/* Passing in an easy_pollset for monitoring of sockets, let
* filters add or remove sockets actions (CURL_POLL_OUT, CURL_POLL_IN).
* This may add a socket or, in case no actions remain, remove
* a socket from the set.
*
* Filter implementations need to call filters "below" *after* they have
* made their adjustments. This allows lower filters to override "upper"
* actions. If a "lower" filter is unable to write, it needs to be able
* to disallow POLL_OUT.
*
* A filter without own restrictions/preferences should not modify
* the pollset. Filters, whose filter "below" is not connected, should
* also do no adjustments.
*
* Examples: a TLS handshake, while ongoing, might remove POLL_IN when it
* needs to write, or vice versa. An HTTP/2 filter might remove POLL_OUT when
* a stream window is exhausted and a WINDOW_UPDATE needs to be received first
* and add instead POLL_IN.
*
* @param cf the filter to ask
* @param data the easy handle the pollset is about
* @param ps the pollset (inout) for the easy handle
*/
typedef void Curl_cft_adjust_pollset(struct Curl_cfilter *cf,
struct Curl_easy *data,
struct easy_pollset *ps);
typedef bool Curl_cft_data_pending(struct Curl_cfilter *cf,
const struct Curl_easy *data);
typedef ssize_t Curl_cft_send(struct Curl_cfilter *cf,
struct Curl_easy *data, /* transfer */
const void *buf, /* data to write */
size_t len, /* amount to write */
bool eos, /* last chunk */
CURLcode *err); /* error to return */
typedef ssize_t Curl_cft_recv(struct Curl_cfilter *cf,
struct Curl_easy *data, /* transfer */
char *buf, /* store data here */
size_t len, /* amount to read */
CURLcode *err); /* error to return */
typedef bool Curl_cft_conn_is_alive(struct Curl_cfilter *cf,
struct Curl_easy *data,
bool *input_pending);
typedef CURLcode Curl_cft_conn_keep_alive(struct Curl_cfilter *cf,
struct Curl_easy *data);
/**
* Events/controls for connection filters, their arguments and
* return code handling. Filter callbacks are invoked "top down".
* Return code handling:
* "first fail" meaning that the first filter returning != CURLE_OK, will
* abort further event distribution and determine the result.
* "ignored" meaning return values are ignored and the event is distributed
* to all filters in the chain. Overall result is always CURLE_OK.
*/
/* data event arg1 arg2 return */
#define CF_CTRL_DATA_ATTACH 1 /* 0 NULL ignored */
#define CF_CTRL_DATA_DETACH 2 /* 0 NULL ignored */
#define CF_CTRL_DATA_SETUP 4 /* 0 NULL first fail */
#define CF_CTRL_DATA_IDLE 5 /* 0 NULL first fail */
#define CF_CTRL_DATA_PAUSE 6 /* on/off NULL first fail */
#define CF_CTRL_DATA_DONE 7 /* premature NULL ignored */
#define CF_CTRL_DATA_DONE_SEND 8 /* 0 NULL ignored */
/* update conn info at connection and data */
#define CF_CTRL_CONN_INFO_UPDATE (256+0) /* 0 NULL ignored */
#define CF_CTRL_FORGET_SOCKET (256+1) /* 0 NULL ignored */
#define CF_CTRL_FLUSH (256+2) /* 0 NULL first fail */
/**
* Handle event/control for the filter.
* Implementations MUST NOT chain calls to cf->next.
*/
typedef CURLcode Curl_cft_cntrl(struct Curl_cfilter *cf,
struct Curl_easy *data,
int event, int arg1, void *arg2);
/**
* Queries to ask via a `Curl_cft_query *query` method on a cfilter chain.
* - MAX_CONCURRENT: the maximum number of parallel transfers the filter
* chain expects to handle at the same time.
* default: 1 if no filter overrides.
* - CONNECT_REPLY_MS: milliseconds until the first indication of a server
* response was received on a connect. For TCP, this
* reflects the time until the socket connected. On UDP
* this gives the time the first bytes from the server
* were received.
* -1 if not determined yet.
* - CF_QUERY_SOCKET: the socket used by the filter chain
* - CF_QUERY_NEED_FLUSH: TRUE iff any of the filters have unsent data
* - CF_QUERY_IP_INFO: res1 says if connection used IPv6, res2 is the
* ip quadruple
*/
/* query res1 res2 */
#define CF_QUERY_MAX_CONCURRENT 1 /* number - */
#define CF_QUERY_CONNECT_REPLY_MS 2 /* number - */
#define CF_QUERY_SOCKET 3 /* - curl_socket_t */
#define CF_QUERY_TIMER_CONNECT 4 /* - struct curltime */
#define CF_QUERY_TIMER_APPCONNECT 5 /* - struct curltime */
#define CF_QUERY_STREAM_ERROR 6 /* error code - */
#define CF_QUERY_NEED_FLUSH 7 /* TRUE/FALSE - */
#define CF_QUERY_IP_INFO 8 /* TRUE/FALSE struct ip_quadruple */
/**
* Query the cfilter for properties. Filters ignorant of a query will
* pass it "down" the filter chain.
*/
typedef CURLcode Curl_cft_query(struct Curl_cfilter *cf,
struct Curl_easy *data,
int query, int *pres1, void *pres2);
/**
* Type flags for connection filters. A filter can have none, one or
* many of those. Use to evaluate state/capabilities of a filter chain.
*
* CF_TYPE_IP_CONNECT: provides an IP connection or sth equivalent, like
* a CONNECT tunnel, a UNIX domain socket, a QUIC
* connection, etc.
* CF_TYPE_SSL: provide SSL/TLS
* CF_TYPE_MULTIPLEX: provides multiplexing of easy handles
* CF_TYPE_PROXY provides proxying
*/
#define CF_TYPE_IP_CONNECT (1 << 0)
#define CF_TYPE_SSL (1 << 1)
#define CF_TYPE_MULTIPLEX (1 << 2)
#define CF_TYPE_PROXY (1 << 3)
/* A connection filter type, e.g. specific implementation. */
struct Curl_cftype {
const char *name; /* name of the filter type */
int flags; /* flags of filter type */
int log_level; /* log level for such filters */
Curl_cft_destroy_this *destroy; /* destroy resources of this cf */
Curl_cft_connect *do_connect; /* establish connection */
Curl_cft_close *do_close; /* close conn */
Curl_cft_shutdown *do_shutdown; /* shutdown conn */
Curl_cft_get_host *get_host; /* host filter talks to */
Curl_cft_adjust_pollset *adjust_pollset; /* adjust transfer poll set */
Curl_cft_data_pending *has_data_pending;/* conn has data pending */
Curl_cft_send *do_send; /* send data */
Curl_cft_recv *do_recv; /* receive data */
Curl_cft_cntrl *cntrl; /* events/control */
Curl_cft_conn_is_alive *is_alive; /* FALSE if conn is dead, Jim! */
Curl_cft_conn_keep_alive *keep_alive; /* try to keep it alive */
Curl_cft_query *query; /* query filter chain */
};
/* A connection filter instance, e.g. registered at a connection */
struct Curl_cfilter {
const struct Curl_cftype *cft; /* the type providing implementation */
struct Curl_cfilter *next; /* next filter in chain */
void *ctx; /* filter type specific settings */
struct connectdata *conn; /* the connection this filter belongs to */
int sockindex; /* the index the filter is installed at */
BIT(connected); /* != 0 iff this filter is connected */
BIT(shutdown); /* != 0 iff this filter has shut down */
};
/* Default implementations for the type functions, implementing nop. */
void Curl_cf_def_destroy_this(struct Curl_cfilter *cf,
struct Curl_easy *data);
/* Default implementations for the type functions, implementing pass-through
* the filter chain. */
void Curl_cf_def_get_host(struct Curl_cfilter *cf, struct Curl_easy *data,
const char **phost, const char **pdisplay_host,
int *pport);
void Curl_cf_def_adjust_pollset(struct Curl_cfilter *cf,
struct Curl_easy *data,
struct easy_pollset *ps);
bool Curl_cf_def_data_pending(struct Curl_cfilter *cf,
const struct Curl_easy *data);
ssize_t Curl_cf_def_send(struct Curl_cfilter *cf, struct Curl_easy *data,
const void *buf, size_t len, bool eos,
CURLcode *err);
ssize_t Curl_cf_def_recv(struct Curl_cfilter *cf, struct Curl_easy *data,
char *buf, size_t len, CURLcode *err);
CURLcode Curl_cf_def_cntrl(struct Curl_cfilter *cf,
struct Curl_easy *data,
int event, int arg1, void *arg2);
bool Curl_cf_def_conn_is_alive(struct Curl_cfilter *cf,
struct Curl_easy *data,
bool *input_pending);
CURLcode Curl_cf_def_conn_keep_alive(struct Curl_cfilter *cf,
struct Curl_easy *data);
CURLcode Curl_cf_def_query(struct Curl_cfilter *cf,
struct Curl_easy *data,
int query, int *pres1, void *pres2);
CURLcode Curl_cf_def_shutdown(struct Curl_cfilter *cf,
struct Curl_easy *data, bool *done);
/**
* Create a new filter instance, unattached to the filter chain.
* Use Curl_conn_cf_add() to add it to the chain.
* @param pcf on success holds the created instance
* @param cft the filter type
* @param ctx the type specific context to use
*/
CURLcode Curl_cf_create(struct Curl_cfilter **pcf,
const struct Curl_cftype *cft,
void *ctx);
/**
* Add a filter instance to the `sockindex` filter chain at connection
* `conn`. The filter must not already be attached. It is inserted at
* the start of the chain (top).
*/
void Curl_conn_cf_add(struct Curl_easy *data,
struct connectdata *conn,
int sockindex,
struct Curl_cfilter *cf);
/**
* Insert a filter (chain) after `cf_at`.
* `cf_new` must not already be attached.
*/
void Curl_conn_cf_insert_after(struct Curl_cfilter *cf_at,
struct Curl_cfilter *cf_new);
/**
* Discard, e.g. remove and destroy `discard` iff
* it still is in the filter chain below `cf`. If `discard`
* is no longer found beneath `cf` return FALSE.
* if `destroy_always` is TRUE, will call `discard`s destroy
* function and free it even if not found in the subchain.
*/
bool Curl_conn_cf_discard_sub(struct Curl_cfilter *cf,
struct Curl_cfilter *discard,
struct Curl_easy *data,
bool destroy_always);
/**
* Discard all cfilters starting with `*pcf` and clearing it afterwards.
*/
void Curl_conn_cf_discard_chain(struct Curl_cfilter **pcf,
struct Curl_easy *data);
/**
* Remove and destroy all filters at chain `sockindex` on connection `conn`.
*/
void Curl_conn_cf_discard_all(struct Curl_easy *data,
struct connectdata *conn,
int sockindex);
CURLcode Curl_conn_cf_connect(struct Curl_cfilter *cf,
struct Curl_easy *data,
bool blocking, bool *done);
void Curl_conn_cf_close(struct Curl_cfilter *cf, struct Curl_easy *data);
ssize_t Curl_conn_cf_send(struct Curl_cfilter *cf, struct Curl_easy *data,
const void *buf, size_t len, bool eos,
CURLcode *err);
ssize_t Curl_conn_cf_recv(struct Curl_cfilter *cf, struct Curl_easy *data,
char *buf, size_t len, CURLcode *err);
CURLcode Curl_conn_cf_cntrl(struct Curl_cfilter *cf,
struct Curl_easy *data,
bool ignore_result,
int event, int arg1, void *arg2);
/**
* Determine if the connection filter chain is using SSL to the remote host
* (or will be once connected).
*/
bool Curl_conn_cf_is_ssl(struct Curl_cfilter *cf);
/**
* Get the socket used by the filter chain starting at `cf`.
* Returns CURL_SOCKET_BAD if not available.
*/
curl_socket_t Curl_conn_cf_get_socket(struct Curl_cfilter *cf,
struct Curl_easy *data);
CURLcode Curl_conn_cf_get_ip_info(struct Curl_cfilter *cf,
struct Curl_easy *data,
int *is_ipv6, struct ip_quadruple *ipquad);
bool Curl_conn_cf_needs_flush(struct Curl_cfilter *cf,
struct Curl_easy *data);
#define CURL_CF_SSL_DEFAULT -1
#define CURL_CF_SSL_DISABLE 0
#define CURL_CF_SSL_ENABLE 1
/**
* Bring the filter chain at `sockindex` for connection `data->conn` into
* connected state. Which will set `*done` to TRUE.
* This can be called on an already connected chain with no side effects.
* When not `blocking`, calls may return without error and `*done != TRUE`,
* while the individual filters negotiated the connection.
*/
CURLcode Curl_conn_connect(struct Curl_easy *data, int sockindex,
bool blocking, bool *done);
/**
* Check if the filter chain at `sockindex` for connection `conn` is
* completely connected.
*/
bool Curl_conn_is_connected(struct connectdata *conn, int sockindex);
/**
* Determine if we have reached the remote host on IP level, e.g.
* have a TCP connection. This turns TRUE before a possible SSL
* handshake has been started/done.
*/
bool Curl_conn_is_ip_connected(struct Curl_easy *data, int sockindex);
/**
* Determine if the connection is using SSL to the remote host
* (or will be once connected). This will return FALSE, if SSL
* is only used in proxying and not for the tunnel itself.
*/
bool Curl_conn_is_ssl(struct connectdata *conn, int sockindex);
/**
* Connection provides multiplexing of easy handles at `socketindex`.
*/
bool Curl_conn_is_multiplex(struct connectdata *conn, int sockindex);
/**
* Close the filter chain at `sockindex` for connection `data->conn`.
* Filters remain in place and may be connected again afterwards.
*/
void Curl_conn_close(struct Curl_easy *data, int sockindex);
/**
* Shutdown the connection at `sockindex` non-blocking, using timeout
* from `data->set.shutdowntimeout`, default DEFAULT_SHUTDOWN_TIMEOUT_MS.
* Will return CURLE_OK and *done == FALSE if not finished.
*/
CURLcode Curl_conn_shutdown(struct Curl_easy *data, int sockindex, bool *done);
/**
* Return if data is pending in some connection filter at chain
* `sockindex` for connection `data->conn`.
*/
bool Curl_conn_data_pending(struct Curl_easy *data,
int sockindex);
/**
* Return TRUE if any of the connection filters at chain `sockindex`
* have data still to send.
*/
bool Curl_conn_needs_flush(struct Curl_easy *data, int sockindex);
/**
* Flush any pending data on the connection filters at chain `sockindex`.
*/
CURLcode Curl_conn_flush(struct Curl_easy *data, int sockindex);
/**
* Return the socket used on data's connection for the index.
* Returns CURL_SOCKET_BAD if not available.
*/
curl_socket_t Curl_conn_get_socket(struct Curl_easy *data, int sockindex);
/**
* Tell filters to forget about the socket at sockindex.
*/
void Curl_conn_forget_socket(struct Curl_easy *data, int sockindex);
/**
* Adjust the pollset for the filter chain startgin at `cf`.
*/
void Curl_conn_cf_adjust_pollset(struct Curl_cfilter *cf,
struct Curl_easy *data,
struct easy_pollset *ps);
/**
* Adjust pollset from filters installed at transfer's connection.
*/
void Curl_conn_adjust_pollset(struct Curl_easy *data,
struct easy_pollset *ps);
/**
* Curl_poll() the filter chain at `cf` with timeout `timeout_ms`.
* Returns 0 on timeout, negative on error or number of sockets
* with requested poll events.
*/
int Curl_conn_cf_poll(struct Curl_cfilter *cf,
struct Curl_easy *data,
timediff_t timeout_ms);
/**
* Receive data through the filter chain at `sockindex` for connection
* `data->conn`. Copy at most `len` bytes into `buf`. Return the
* actual number of bytes copied or a negative value on error.
* The error code is placed into `*code`.
*/
ssize_t Curl_cf_recv(struct Curl_easy *data, int sockindex, char *buf,
size_t len, CURLcode *code);
/**
* Send `len` bytes of data from `buf` through the filter chain `sockindex`
* at connection `data->conn`. Return the actual number of bytes written
* or a negative value on error.
* The error code is placed into `*code`.
*/
ssize_t Curl_cf_send(struct Curl_easy *data, int sockindex,
const void *buf, size_t len, bool eos, CURLcode *code);
/**
* The easy handle `data` is being attached to `conn`. This does
* not mean that data will actually do a transfer. Attachment is
* also used for temporary actions on the connection.
*/
void Curl_conn_ev_data_attach(struct connectdata *conn,
struct Curl_easy *data);
/**
* The easy handle `data` is being detached (no longer served)
* by connection `conn`. All filters are informed to release any resources
* related to `data`.
* Note: there may be several `data` attached to a connection at the same
* time.
*/
void Curl_conn_ev_data_detach(struct connectdata *conn,
struct Curl_easy *data);
/**
* Notify connection filters that they need to setup data for
* a transfer.
*/
CURLcode Curl_conn_ev_data_setup(struct Curl_easy *data);
/**
* Notify connection filters that now would be a good time to
* perform any idle, e.g. time related, actions.
*/
CURLcode Curl_conn_ev_data_idle(struct Curl_easy *data);
/**
* Notify connection filters that the transfer represented by `data`
* is done with sending data (e.g. has uploaded everything).
*/
void Curl_conn_ev_data_done_send(struct Curl_easy *data);
/**
* Notify connection filters that the transfer represented by `data`
* is finished - eventually premature, e.g. before being complete.
*/
void Curl_conn_ev_data_done(struct Curl_easy *data, bool premature);
/**
* Notify connection filters that the transfer of data is paused/unpaused.
*/
CURLcode Curl_conn_ev_data_pause(struct Curl_easy *data, bool do_pause);
/**
* Check if FIRSTSOCKET's cfilter chain deems connection alive.
*/
bool Curl_conn_is_alive(struct Curl_easy *data, struct connectdata *conn,
bool *input_pending);
/**
* Try to upkeep the connection filters at sockindex.
*/
CURLcode Curl_conn_keep_alive(struct Curl_easy *data,
struct connectdata *conn,
int sockindex);
#ifdef UNITTESTS
void Curl_cf_def_close(struct Curl_cfilter *cf, struct Curl_easy *data);
#endif
void Curl_conn_get_host(struct Curl_easy *data, int sockindex,
const char **phost, const char **pdisplay_host,
int *pport);
/**
* Get the maximum number of parallel transfers the connection
* expects to be able to handle at `sockindex`.
*/
size_t Curl_conn_get_max_concurrent(struct Curl_easy *data,
struct connectdata *conn,
int sockindex);
/**
* Get the underlying error code for a transfer stream or 0 if not known.
*/
int Curl_conn_get_stream_error(struct Curl_easy *data,
struct connectdata *conn,
int sockindex);
/**
* Get the index of the given socket in the connection's sockets.
* Useful in calling `Curl_conn_send()/Curl_conn_recv()` with the
* correct socket index.
*/
int Curl_conn_sockindex(struct Curl_easy *data, curl_socket_t sockfd);
/*
* Receive data on the connection, using FIRSTSOCKET/SECONDARYSOCKET.
* Will return CURLE_AGAIN iff blocked on receiving.
*/
CURLcode Curl_conn_recv(struct Curl_easy *data, int sockindex,
char *buf, size_t buffersize,
ssize_t *pnread);
/*
* Send data on the connection, using FIRSTSOCKET/SECONDARYSOCKET.
* Will return CURLE_AGAIN iff blocked on sending.
*/
CURLcode Curl_conn_send(struct Curl_easy *data, int sockindex,
const void *buf, size_t blen, bool eos,
size_t *pnwritten);
void Curl_pollset_reset(struct Curl_easy *data,
struct easy_pollset *ps);
/* Change the poll flags (CURL_POLL_IN/CURL_POLL_OUT) to the poll set for
* socket `sock`. If the socket is not already part of the poll set, it
* will be added.
* If the socket is present and all poll flags are cleared, it will be removed.
*/
void Curl_pollset_change(struct Curl_easy *data,
struct easy_pollset *ps, curl_socket_t sock,
int add_flags, int remove_flags);
void Curl_pollset_set(struct Curl_easy *data,
struct easy_pollset *ps, curl_socket_t sock,
bool do_in, bool do_out);
#define Curl_pollset_add_in(data, ps, sock) \
Curl_pollset_change((data), (ps), (sock), CURL_POLL_IN, 0)
#define Curl_pollset_add_out(data, ps, sock) \
Curl_pollset_change((data), (ps), (sock), CURL_POLL_OUT, 0)
#define Curl_pollset_add_inout(data, ps, sock) \
Curl_pollset_change((data), (ps), (sock), \
CURL_POLL_IN|CURL_POLL_OUT, 0)
#define Curl_pollset_set_in_only(data, ps, sock) \
Curl_pollset_change((data), (ps), (sock), \
CURL_POLL_IN, CURL_POLL_OUT)
#define Curl_pollset_set_out_only(data, ps, sock) \
Curl_pollset_change((data), (ps), (sock), \
CURL_POLL_OUT, CURL_POLL_IN)
void Curl_pollset_add_socks(struct Curl_easy *data,
struct easy_pollset *ps,
int (*get_socks_cb)(struct Curl_easy *data,
curl_socket_t *socks));
/**
* Check if the pollset, as is, wants to read and/or write regarding
* the given socket.
*/
void Curl_pollset_check(struct Curl_easy *data,
struct easy_pollset *ps, curl_socket_t sock,
bool *pwant_read, bool *pwant_write);
/**
* Types and macros used to keep the current easy handle in filter calls,
* allowing for nested invocations. See #10336.
*
* `cf_call_data` is intended to be a member of the cfilter's `ctx` type.
* A filter defines the macro `CF_CTX_CALL_DATA` to give access to that.
*
* With all values 0, the default, this indicates that there is no cfilter
* call with `data` ongoing.
* Macro `CF_DATA_SAVE` preserves the current `cf_call_data` in a local
* variable and sets the `data` given, incrementing the `depth` counter.
*
* Macro `CF_DATA_RESTORE` restores the old values from the local variable,
* while checking that `depth` values are as expected (debug build), catching
* cases where a "lower" RESTORE was not called.
*
* Finally, macro `CF_DATA_CURRENT` gives the easy handle of the current
* invocation.
*/
struct cf_call_data {
struct Curl_easy *data;
#ifdef DEBUGBUILD
int depth;
#endif
};
/**
* define to access the `struct cf_call_data for a cfilter. Normally
* a member in the cfilter's `ctx`.
*
* #define CF_CTX_CALL_DATA(cf) -> struct cf_call_data instance
*/
#ifdef DEBUGBUILD
#define CF_DATA_SAVE(save, cf, data) \
do { \
(save) = CF_CTX_CALL_DATA(cf); \
DEBUGASSERT((save).data == NULL || (save).depth > 0); \
CF_CTX_CALL_DATA(cf).depth++; \
CF_CTX_CALL_DATA(cf).data = (struct Curl_easy *)data; \
} while(0)
#define CF_DATA_RESTORE(cf, save) \
do { \
DEBUGASSERT(CF_CTX_CALL_DATA(cf).depth == (save).depth + 1); \
DEBUGASSERT((save).data == NULL || (save).depth > 0); \
CF_CTX_CALL_DATA(cf) = (save); \
} while(0)
#else /* DEBUGBUILD */
#define CF_DATA_SAVE(save, cf, data) \
do { \
(save) = CF_CTX_CALL_DATA(cf); \
CF_CTX_CALL_DATA(cf).data = (struct Curl_easy *)data; \
} while(0)
#define CF_DATA_RESTORE(cf, save) \
do { \
CF_CTX_CALL_DATA(cf) = (save); \
} while(0)
#endif /* !DEBUGBUILD */
#define CF_DATA_CURRENT(cf) \
((cf)? (CF_CTX_CALL_DATA(cf).data) : NULL)
#endif /* HEADER_CURL_CFILTERS_H */
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