[pulseaudio-discuss] Few questions about PA API
David Henningsson
david.henningsson at canonical.com
Tue Jun 10 03:19:36 PDT 2014
Thanks for the patch. Overall I think this is good new functionality.
Here's a review, which is mostly about details:
On 2014-04-15 02:14, Lukasz Marek wrote:
>
> From ab9e95ab62602ed107b5d46642149de7ead15c10 Mon Sep 17 00:00:00 2001
> From: Lukasz Marek<lukasz.m.luki2 at gmail.com>
> Date: Tue, 15 Apr 2014 02:08:23 +0200
> Subject: [PATCH] Add pa_stream_write_ext_free() function.
Missing prefix, maybe "Client API:" would be good here, so the subject
becomes:
"Client API: Add Add pa_stream_write_ext_free function"
> New function allows to pass data pointer that is a member
> of the outer structure that need to be freed too when data
> is not needed anymore.
>
> Signed-off-by: Lukasz Marek<lukasz.m.luki2 at gmail.com>
> ---
> src/map-file | 1 +
> src/pulse/stream.c | 20 ++++++++++++++++----
> src/pulse/stream.h | 11 +++++++++++
> src/pulsecore/memblock.c | 14 ++++++++++++--
> src/pulsecore/memblock.h | 2 +-
> 5 files changed, 41 insertions(+), 7 deletions(-)
>
> diff --git a/src/map-file b/src/map-file
> index dc36fdc..5159829 100644
> --- a/src/map-file
> +++ b/src/map-file
> @@ -330,6 +330,7 @@ pa_stream_update_sample_rate;
> pa_stream_update_timing_info;
> pa_stream_writable_size;
> pa_stream_write;
> +pa_stream_write_ext_free;
> pa_strerror;
> pa_sw_cvolume_divide;
> pa_sw_cvolume_divide_scalar;
> diff --git a/src/pulse/stream.c b/src/pulse/stream.c
> index 8e35c29..2c9a777 100644
> --- a/src/pulse/stream.c
> +++ b/src/pulse/stream.c
> @@ -1464,13 +1464,14 @@ int pa_stream_cancel_write(
> return 0;
> }
>
> -int pa_stream_write(
> +int pa_stream_write_ext_free(
> pa_stream *s,
> const void *data,
> size_t length,
> pa_free_cb_t free_cb,
> int64_t offset,
> - pa_seek_mode_t seek) {
> + pa_seek_mode_t seek,
> + const void *free_cb_data) {
I think it would be wise to switch order here, i e, to have the free_cb
just before free_cb_data.
Also, because "userdata" usually is "void *" (not "const void *"), maybe
it would make more sense to have free_cb_data as "void *" too?
>
> pa_assert(s);
> pa_assert(PA_REFCNT_VALUE(s) >= 1);
> @@ -1519,7 +1520,7 @@ int pa_stream_write(
> chunk.index = 0;
>
> if (free_cb && !pa_pstream_get_shm(s->context->pstream)) {
> - chunk.memblock = pa_memblock_new_user(s->context->mempool, (void*) t_data, t_length, free_cb, 1);
> + chunk.memblock = pa_memblock_new_user(s->context->mempool, (void*) t_data, t_length, free_cb, 1, (void*) free_cb_data);
> chunk.length = t_length;
> } else {
> void *d;
> @@ -1544,7 +1545,7 @@ int pa_stream_write(
> }
>
> if (free_cb && pa_pstream_get_shm(s->context->pstream))
> - free_cb((void*) data);
> + free_cb((void*) free_cb_data);
> }
>
> /* This is obviously wrong since we ignore the seeking index . But
> @@ -1591,6 +1592,17 @@ int pa_stream_write(
> return 0;
> }
>
> +int pa_stream_write(
> + pa_stream *s,
> + const void *data,
> + size_t length,
> + pa_free_cb_t free_cb,
> + int64_t offset,
> + pa_seek_mode_t seek) {
> +
> + return pa_stream_write_ext_free(s, data, length, free_cb, offset, seek, data);
> +}
> +
> int pa_stream_peek(pa_stream *s, const void **data, size_t *length) {
> pa_assert(s);
> pa_assert(PA_REFCNT_VALUE(s) >= 1);
> diff --git a/src/pulse/stream.h b/src/pulse/stream.h
> index 7ceb569..6fbd663 100644
> --- a/src/pulse/stream.h
> +++ b/src/pulse/stream.h
> @@ -554,6 +554,17 @@ int pa_stream_write(
> int64_t offset, /**< Offset for seeking, must be 0 for upload streams */
> pa_seek_mode_t seek /**< Seek mode, must be PA_SEEK_RELATIVE for upload streams */);
>
> +/** Function does exactly the same as pa_stream_write() with the difference
> + * that free_cb_data is passed to free_cb instead of data. \since 6.0 */
> +int pa_stream_write_ext_free(
> + pa_stream *p /**< The stream to use */,
> + const void *data /**< The data to write */,
> + size_t nbytes /**< The length of the data to write in bytes */,
> + pa_free_cb_t free_cb /**< A cleanup routine for the data or NULL to request an internal copy */,
> + int64_t offset, /**< Offset for seeking, must be 0 for upload streams */
Nitpick: Inconsistent comma placement. I saw it was there in
pa_stream_write too, but let's fix it anyway :-)
> + pa_seek_mode_t seek /**< Seek mode, must be PA_SEEK_RELATIVE for upload streams */,
> + const void *free_cb_data /**< Argument passed to free_cb function */);
> +
> /** Read the next fragment from the buffer (for recording streams).
> * If there is data at the current read index, \a data will point to
> * the actual data and \a nbytes will contain the size of the data in
> diff --git a/src/pulsecore/memblock.c b/src/pulsecore/memblock.c
> index 9cc02c1..3d75d99 100644
> --- a/src/pulsecore/memblock.c
> +++ b/src/pulsecore/memblock.c
> @@ -83,6 +83,8 @@ struct pa_memblock {
> struct {
> /* If type == PA_MEMBLOCK_USER this points to a function for freeing this memory block */
> pa_free_cb_t free_cb;
> + /* If type == PA_MEMBLOCK_USER this is passed as free_cb argument */
> + pa_atomic_ptr_t free_cb_data;
Hmm, I'm not sure why free_cb_data needs to be atomic. If it's only set
once in the creation of the memblock, then why not keep it as "void *"
consistently?
> } user;
>
> struct {
> @@ -387,7 +389,13 @@ pa_memblock *pa_memblock_new_fixed(pa_mempool *p, void *d, size_t length, bool r
> }
>
> /* No lock necessary */
> -pa_memblock *pa_memblock_new_user(pa_mempool *p, void *d, size_t length, pa_free_cb_t free_cb, bool read_only) {
> +pa_memblock *pa_memblock_new_user(
> + pa_mempool *p,
> + void *d,
> + size_t length,
> + pa_free_cb_t free_cb,
> + bool read_only,
Same as previous comment; keep free_cb next to free_cb_data
> + void *free_cb_data) {
> pa_memblock *b;
>
> pa_assert(p);
> @@ -410,6 +418,7 @@ pa_memblock *pa_memblock_new_user(pa_mempool *p, void *d, size_t length, pa_free
> pa_atomic_store(&b->please_signal, 0);
>
> b->per_type.user.free_cb = free_cb;
> + pa_atomic_ptr_store(&b->per_type.user.free_cb_data, free_cb_data);
>
> stat_add(b);
> return b;
> @@ -513,7 +522,7 @@ static void memblock_free(pa_memblock *b) {
> switch (b->type) {
> case PA_MEMBLOCK_USER :
> pa_assert(b->per_type.user.free_cb);
> - b->per_type.user.free_cb(pa_atomic_ptr_load(&b->data));
> + b->per_type.user.free_cb(pa_atomic_ptr_load(&b->per_type.user.free_cb_data));
>
> /* Fall through */
>
> @@ -647,6 +656,7 @@ static void memblock_make_local(pa_memblock *b) {
> /* Humm, not enough space in the pool, so lets allocate the memory with malloc() */
> b->per_type.user.free_cb = pa_xfree;
> pa_atomic_ptr_store(&b->data, pa_xmemdup(pa_atomic_ptr_load(&b->data), b->length));
> + pa_atomic_ptr_store(&b->per_type.user.free_cb_data, pa_atomic_ptr_load(&b->data));
>
> b->type = PA_MEMBLOCK_USER;
> b->read_only = false;
> diff --git a/src/pulsecore/memblock.h b/src/pulsecore/memblock.h
> index 502f207..0bfdc92 100644
> --- a/src/pulsecore/memblock.h
> +++ b/src/pulsecore/memblock.h
> @@ -85,7 +85,7 @@ pa_memblock *pa_memblock_new(pa_mempool *, size_t length);
> pa_memblock *pa_memblock_new_pool(pa_mempool *, size_t length);
>
> /* Allocate a new memory block of type PA_MEMBLOCK_USER */
> -pa_memblock *pa_memblock_new_user(pa_mempool *, void *data, size_t length, pa_free_cb_t free_cb, bool read_only);
> +pa_memblock *pa_memblock_new_user(pa_mempool *, void *data, size_t length, pa_free_cb_t free_cb, bool read_only, void *free_cb_data);
>
> /* A special case of pa_memblock_new_user: take a memory buffer previously allocated with pa_xmalloc() */
> #define pa_memblock_new_malloced(p,data,length) pa_memblock_new_user(p, data, length, pa_xfree, 0)
--
David Henningsson, Canonical Ltd.
https://launchpad.net/~diwic
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