From de7f7a84a32045a706559ae37ccaa325fe9b2720 Mon Sep 17 00:00:00 2001 From: Nick Mathewson Date: Fri, 23 Jan 2009 18:03:45 +0000 Subject: [PATCH] Remove in_callbacks check: allow full recursion in evbuffer callbacks. If you get yourself in an infinite loop, that's not our fault. Note this in the docs. Also reindent some docs now that my tabs match Niels's. svn:r1046 --- buffer.c | 5 +---- evbuffer-internal.h | 1 - include/event2/buffer.h | 48 +++++++++++++++++++++-------------------- 3 files changed, 26 insertions(+), 28 deletions(-) diff --git a/buffer.c b/buffer.c index 0a7b95cf..ee930bf0 100644 --- a/buffer.c +++ b/buffer.c @@ -116,17 +116,14 @@ static inline void evbuffer_invoke_callbacks(struct evbuffer *buffer, size_t old_size) { size_t new_size = buffer->total_len; - if (!TAILQ_EMPTY(&buffer->callbacks) && old_size != new_size - && !buffer->in_callbacks) { + if (!TAILQ_EMPTY(&buffer->callbacks) && old_size != new_size) { struct evbuffer_cb_entry *cbent, *next; - buffer->in_callbacks = 1; for (cbent = TAILQ_FIRST(&buffer->callbacks); cbent != TAILQ_END(&buffer->callbacks); cbent = next) { next = TAILQ_NEXT(cbent, next); cbent->cb(buffer, old_size, new_size, cbent->cbarg); } - buffer->in_callbacks = 0; } } diff --git a/evbuffer-internal.h b/evbuffer-internal.h index 5f7fc109..bd4130e6 100644 --- a/evbuffer-internal.h +++ b/evbuffer-internal.h @@ -56,7 +56,6 @@ struct evbuffer { void *cbarg; TAILQ_HEAD(evbuffer_cb_queue, evbuffer_cb_entry) callbacks; - unsigned char in_callbacks; }; struct evbuffer_chain { diff --git a/include/event2/buffer.h b/include/event2/buffer.h index 3fbe6fe0..00691fea 100644 --- a/include/event2/buffer.h +++ b/include/event2/buffer.h @@ -319,23 +319,25 @@ int evbuffer_read(struct evbuffer *buffer, evutil_socket_t fd, int howmuch); unsigned char *evbuffer_find(struct evbuffer *buffer, const unsigned char *what, size_t len); -/** Type definition for a callback that is invoked whenever[1] data is added or - removed from an evbuffer. +/** Type definition for a callback that is invoked whenever data is added or + removed from an evbuffer. - An evbuffer may have one or more callbacks set at a time. The order - in which they are exectuded is undefined. + An evbuffer may have one or more callbacks set at a time. The order + in which they are exectuded is undefined. - A callback function may add more callbacks, or remove itself from the - list of callbacks, or add or remove data from the buffer. It may not - remove another callback from the list. + A callback function may add more callbacks, or remove itself from the + list of callbacks, or add or remove data from the buffer. It may not + remove another callback from the list. - [1] If the length of the buffer changes because of a callback, the - callbacks are not invoked again, to prevent an infinite loop. + If a callback adds or removes data from the buffer or from another + buffer, this can cause a recursive invocation of your callback or + other callbacks. If you ask for an infinite loop, you might just get + one: watch out! - @param buffer the buffer whose size has changed - @param old_len the previous length of the buffer - @param new_len thee current length of the buffer - @param arg a pointer to user data + @param buffer the buffer whose size has changed + @param old_len the previous length of the buffer + @param new_len thee current length of the buffer + @param arg a pointer to user data */ typedef void (*evbuffer_cb)(struct evbuffer *buffer, size_t old_len, size_t new_len, void *arg); @@ -354,21 +356,21 @@ struct evbuffer_cb_entry; struct evbuffer_cb_entry *evbuffer_add_cb(struct evbuffer *buffer, evbuffer_cb cb, void *cbarg); /** Remove a callback from an evbuffer, given a handle returned from - evbuffer_add_cb. + evbuffer_add_cb. - Calling this function invalidates the handle. + Calling this function invalidates the handle. - @return 0 if a callback was removed, or -1 if no matching callback was - found. + @return 0 if a callback was removed, or -1 if no matching callback was + found. */ int evbuffer_remove_cb_entry(struct evbuffer *buffer, - struct evbuffer_cb_entry *ent); + struct evbuffer_cb_entry *ent); /** Remove a callback from an evbuffer, given the function and argument - used to add it. + used to add it. - @return 0 if a callback was removed, or -1 if no matching callback was - found. + @return 0 if a callback was removed, or -1 if no matching callback was + found. */ int evbuffer_remove_cb(struct evbuffer *buffer, evbuffer_cb cb, void *cbarg); @@ -409,8 +411,8 @@ void evbuffer_prepend_buffer(struct evbuffer *dst, struct evbuffer* src); A better find-string that returns a smart offset structure rather than a pointer. It should also be able to start searching _at_ an offset. - A check-representation functions for testing, so we can assert() that - nothing has gone screwy inside an evbuffer. + A check-representation functions for testing, so we can assert() that + nothing has gone screwy inside an evbuffer. */ /** deprecated in favor of calling the functions directly */ -- 2.40.0