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0933f12d28
There are multiple reasons to do this. One big reason is the license:
talloc is LGPLv3+, which forces mpv to be licensed as GPLv3+.
Another one is that our talloc copy contains modifications, which makes
it essentially incompatible with upstream talloc (in particular, our
version aborts on out of memory conditions - well, it wasn't my idea).
Updating from upstream is also a bit involved - the talloc source is
not really organized in a way to allow copying it into projects (and
this isn't an intended use-case).
Finally, talloc is kind of big and bloated. The replacement halves the
amount of code - mainly because we didn't use all talloc features. It's
even more extreme if you compare upstream talloc (~4700 lines) and the
new allocator without talloc compat (~900 lines).
The replacement provides all features we need. It also doesn't clash
with talloc. (The talloc compatibility wrapper uses macros to avoid
introducing linker-level symbols which could clash with libtalloc.)
It also tries to lower the overhead (only 4 words opposed to 10 words
in talloc for leaf nodes in release mode). Debugging features like leak
reporting can be enabled at compile time and add somewhat more overhead.
Though I'm not sure whether the overhead reduction was actually
successful: allocations with children need an "extra" header, which adds
plenty of overhead, and it turns out that almost half of all allocations
have children. Maybe the implementation could be simplified and the
extra header removed - even then, overhead would be lower than talloc's.
Currently, debugging features can be entirely deactivated by defining
NDEBUG - I'm not sure if anything defines this directly yet, though.
Unlike in talloc, the leak reporting stuff is thread-safe. (That's also
why it's far less elegant, and requires extra list pointers.)
Comes with a compatibility layer, so no changes to mpv source code
are needed. The idea is that we will pretend to be using talloc for
a while, so that we can revert to our old talloc implementation at
any time for debugging purposes.
Some inspiration was taken from Mesa's ralloc:
http://cgit.freedesktop.org/mesa/mesa/tree/src/glsl/ralloc.h
This is another talloc replacement, but lacks some features we need
(getting size of an allocation, debugging features, being able to
access children in the dtor).
There's some information in ta/README what will happen next and how the
transition is expected to progress.
75 lines
3.5 KiB
C
75 lines
3.5 KiB
C
/* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#ifndef TA_TALLOC_H_
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#define TA_TALLOC_H_
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#include "ta.h"
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// Note: all talloc wrappers are wired to the "x" functions, which abort on OOM.
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// libtalloc doesn't do that, but the mplayer2 internal copy of it did.
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#define talloc ta_xnew
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#define talloc_zero ta_xznew
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#define talloc_array ta_xnew_array
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#define talloc_zero_array ta_xznew_array
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#define talloc_array_size ta_xnew_array_size
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#define talloc_realloc ta_xrealloc
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#define talloc_ptrtype ta_xnew_ptrtype
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#define talloc_array_ptrtype ta_xnew_array_ptrtype
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#define talloc_steal ta_xsteal
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#define talloc_realloc_size ta_xrealloc_size
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#define talloc_new ta_xnew_context
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#define talloc_set_destructor ta_xset_destructor
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#define talloc_parent ta_find_parent
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#define talloc_enable_leak_report ta_enable_leak_report
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#define talloc_size ta_xalloc_size
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#define talloc_zero_size ta_xzalloc_size
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#define talloc_get_size ta_get_size
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#define talloc_free_children ta_free_children
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#define talloc_free ta_free
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#define talloc_memdup ta_xmemdup
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#define talloc_strdup ta_xstrdup
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#define talloc_strndup ta_xstrndup
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#define talloc_asprintf ta_xasprintf
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#define talloc_vasprintf ta_xvasprintf
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// Don't define linker-level symbols, as that would clash with real libtalloc.
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#define talloc_strdup_append ta_talloc_strdup_append
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#define talloc_strdup_append_buffer ta_talloc_strdup_append_buffer
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#define talloc_strndup_append ta_talloc_strndup_append
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#define talloc_strndup_append_buffer ta_talloc_strndup_append_buffer
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#define talloc_vasprintf_append ta_talloc_vasprintf_append
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#define talloc_vasprintf_append_buffer ta_talloc_vasprintf_append_buffer
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#define talloc_asprintf_append ta_talloc_asprintf_append
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#define talloc_asprintf_append_buffer ta_talloc_asprintf_append_buffer
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char *ta_talloc_strdup(void *t, const char *p);
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char *ta_talloc_strdup_append(char *s, const char *a);
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char *ta_talloc_strdup_append_buffer(char *s, const char *a);
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char *ta_talloc_strndup(void *t, const char *p, size_t n);
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char *ta_talloc_strndup_append(char *s, const char *a, size_t n);
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char *ta_talloc_strndup_append_buffer(char *s, const char *a, size_t n);
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char *ta_talloc_vasprintf_append(char *s, const char *fmt, va_list ap) TA_PRF(2, 0);
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char *ta_talloc_vasprintf_append_buffer(char *s, const char *fmt, va_list ap) TA_PRF(2, 0);
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char *ta_talloc_asprintf_append(char *s, const char *fmt, ...) TA_PRF(2, 3);
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char *ta_talloc_asprintf_append_buffer(char *s, const char *fmt, ...) TA_PRF(2, 3);
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#endif
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