[vlc-devel] [PATCH] aout: add device cycling helper

[Rémi Denis-Courmont]

since there is anyway a ToCToU situation now, I don't see the point of the helper, and even less of the unlocked function.

Le 28 novembre 2018 16:47:22 GMT+02:00, Victorien Le Couviour--Tuffet <victorien.lecouviour.tuffet at gmail.com> a écrit :
>---
> include/vlc_aout.h        |  1 +
> src/audio_output/output.c | 94 ++++++++++++++++++++++++++++++++-------
> src/libvlccore.sym        |  1 +
> 3 files changed, 81 insertions(+), 15 deletions(-)
>
>diff --git a/include/vlc_aout.h b/include/vlc_aout.h
>index aa49884001..ef78127c13 100644
>--- a/include/vlc_aout.h
>+++ b/include/vlc_aout.h
>@@ -373,6 +373,7 @@ VLC_API int aout_MuteGet (audio_output_t *);
> VLC_API int aout_MuteSet (audio_output_t *, bool);
> VLC_API char *aout_DeviceGet (audio_output_t *);
> VLC_API int aout_DeviceSet (audio_output_t *, const char *);
>+VLC_API int aout_DeviceNext (audio_output_t *, char **);
> VLC_API int aout_DevicesList (audio_output_t *, char ***, char ***);
> 
> /**
>diff --git a/src/audio_output/output.c b/src/audio_output/output.c
>index 019797c5ef..ef643260b0 100644
>--- a/src/audio_output/output.c
>+++ b/src/audio_output/output.c
>@@ -701,24 +701,15 @@ int aout_DeviceSet (audio_output_t *aout, const
>char *id)
>     return ret ? -1 : 0;
> }
> 
>-/**
>- * Enumerates possible audio output devices.
>- *
>- * The function will heap-allocate two tables of heap-allocated
>strings;
>- * the caller is responsible for freeing all strings and both tables.
>- *
>- * \param ids pointer to a table of device identifiers [OUT]
>- * \param names pointer to a table of device human-readable
>descriptions [OUT]
>- * \return the number of devices, or negative on error.
>- * \note In case of error, *ids and *names are undefined.
>- */
>-int aout_DevicesList (audio_output_t *aout, char ***ids, char
>***names)
>+static int aout_DevicesListLocked(audio_output_t *aout,
>+                                  char ***ids, char ***names)
> {
>     aout_owner_t *owner = aout_owner (aout);
>+    vlc_mutex_assert(&owner->lock);
>+    vlc_mutex_assert(&owner->dev.lock);
>     char **tabid, **tabname;
>     unsigned i = 0;
> 
>-    vlc_mutex_lock (&owner->dev.lock);
>     tabid = vlc_alloc (owner->dev.count, sizeof (*tabid));
>     tabname = vlc_alloc (owner->dev.count, sizeof (*tabname));
> 
>@@ -743,12 +734,10 @@ int aout_DevicesList (audio_output_t *aout, char
>***ids, char ***names)
> 
>         i++;
>     }
>-    vlc_mutex_unlock (&owner->dev.lock);
> 
>     return i;
> 
> error:
>-    vlc_mutex_unlock(&owner->dev.lock);
>     while (i > 0)
>     {
>         i--;
>@@ -760,6 +749,81 @@ error:
>     return -1;
> }
> 
>+/**
>+ * Enumerates possible audio output devices.
>+ *
>+ * The function will heap-allocate two tables of heap-allocated
>strings;
>+ * the caller is responsible for freeing all strings and both tables.
>+ *
>+ * \param ids pointer to a table of device identifiers [OUT]
>+ * \param names pointer to a table of device human-readable
>descriptions [OUT]
>+ * \return the number of devices, or negative on error.
>+ * \note In case of error, *ids and *names are undefined.
>+ */
>+int aout_DevicesList (audio_output_t *aout, char ***ids, char
>***names)
>+{
>+    aout_OutputLock(aout);
>+    vlc_mutex_t *lock = &aout_owner(aout)->dev.lock;
>+    vlc_mutex_lock(lock);
>+    int ret = aout_DevicesListLocked(aout, ids, names);
>+    vlc_mutex_unlock(lock);
>+    aout_OutputUnlock(aout);
>+    return ret;
>+}
>+
>+/**
>+ * Cycle through audio output devices.
>+ * \param p_name pointer to the selected device human-readable
>description [OUT]
>+ * \return zero on success, non-zero on error.
>+ */
>+int aout_DeviceNext (audio_output_t *aout, char **p_name)
>+{
>+    int ret = -1;
>+    aout_owner_t *owner = aout_owner(aout);
>+    aout_OutputLock(aout);
>+    vlc_mutex_lock(&owner->dev.lock);
>+    bool locked = true;
>+
>+    char **ids, **names;
>+    int n = aout_DevicesListLocked(aout, &ids, &names);
>+    if (n == -1)
>+        goto end;
>+    char *device = aout_DeviceGet(aout);
>+    if (!device)
>+        goto no_dev;
>+
>+    int index;
>+    for (index = 0; index < n; ++index)
>+        if (!strcmp(ids[index], device))
>+        {
>+            index = (index + 1) % n;
>+            break;
>+        }
>+    vlc_mutex_unlock(&owner->dev.lock);
>+    aout_OutputUnlock(aout);
>+    locked = false;
>+    ret = aout_DeviceSet(aout, ids[index]);
>+    if (p_name != NULL)
>+        *p_name = strdup(names[index]);
>+
>+    free(device);
>+no_dev:
>+    for (int i = 0; i < n; ++i)
>+    {
>+        free(ids[i]);
>+        free(names[i]);
>+    }
>+    free(ids);
>+    free(names);
>+end:
>+    if (locked)
>+    {
>+        vlc_mutex_unlock(&owner->dev.lock);
>+        aout_OutputUnlock(aout);
>+    }
>+    return ret;
>+}
>+
> static void aout_ChangeViewpoint(audio_output_t *aout,
>                                  const vlc_viewpoint_t *p_viewpoint)
> {
>diff --git a/src/libvlccore.sym b/src/libvlccore.sym
>index d4db4ccc51..41af4b48db 100644
>--- a/src/libvlccore.sym
>+++ b/src/libvlccore.sym
>@@ -20,6 +20,7 @@ aout_MuteSet
> aout_MuteGet
> aout_DeviceGet
> aout_DeviceSet
>+aout_DeviceNext
> aout_DevicesList
> aout_FiltersNew
> aout_FiltersChangeViewpoint
>-- 
>2.19.1
>
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