Use doubly linked list for filter chaining

src/misc/filter_chain.c

@@ -26,9 +26,9 @@
 #endif
 
 #include <vlc_filter.h>
-#include <vlc_arrays.h>
 #include <vlc_osd.h>
 #include <libvlc.h>
+#include <assert.h>
 
 typedef struct
 {
@@ -38,10 +38,27 @@ typedef struct
 
 } filter_chain_allocator_t;
 
-static int  AllocatorInit( const filter_chain_allocator_t *, filter_t * );
-static void AllocatorClean( const filter_chain_allocator_t *, filter_t * );
+typedef struct chained_filter_t
+{
+    /* Public part of the filter structure */
+    filter_t filter;
+    /* Private filter chain data (shhhh!) */
+    struct chained_filter_t *prev, *next;
+    vlc_mouse_t *mouse;
+} chained_filter_t;
+
+/* Only use this with filter objects from _this_ C module */
+static inline chained_filter_t *chained (filter_t *filter)
+{
+    return (chained_filter_t *)filter;
+}
 
-static bool IsInternalVideoAllocator( filter_t * );
+static int  AllocatorInit( const filter_chain_allocator_t *,
+                           chained_filter_t * );
+static void AllocatorClean( const filter_chain_allocator_t *,
+                            chained_filter_t * );
+
+static bool IsInternalVideoAllocator( chained_filter_t * );
 
 static int  InternalVideoInit( filter_t *, void * );
 static void InternalVideoClean( filter_t * );
@@ -55,27 +72,16 @@ static const filter_chain_allocator_t internal_video_allocator = {
 /* */
 struct filter_chain_t
 {
-    /* Parent object */
-    vlc_object_t *p_this;
-
-    /* List of filters */
-    vlc_array_t filters;
-    vlc_array_t mouses;
+    vlc_object_t *p_this; /**< Owner object */
+    filter_chain_allocator_t allocator; /**< Owner allocation callbacks */
 
-    /* Capability of all the filters in the chain */
-    char *psz_capability;
+    chained_filter_t *first, *last; /**< List of filters */
 
-    /* Input format (read only) */
-    es_format_t fmt_in;
-
-    /* allow changing fmt_out if true */
-    bool b_allow_fmt_out_change;
-
-    /* Output format (writable depending on ... */
-    es_format_t fmt_out;
-
-    /* User provided allocator */
-    filter_chain_allocator_t allocator;
+    es_format_t fmt_in; /**< Chain input format (constant) */
+    es_format_t fmt_out; /**< Chain current output format */
+    unsigned length; /**< Number of filters */
+    bool b_allow_fmt_out_change; /**< Can the output format be changed? */
+    char psz_capability[1]; /**< Module capability for all chained filters */
 };
 
 /**
@@ -101,21 +107,19 @@ filter_chain_t *__filter_chain_New( vlc_object_t *p_this,
                                     void (*pf_buffer_allocation_clean)( filter_t * ),
                                     void *p_buffer_allocation_data )
 {
-    filter_chain_t *p_chain = malloc( sizeof( *p_chain ) );
+    assert( p_this );
+    assert( psz_capability );
+
+    size_t size = sizeof(filter_chain_t) + strlen(psz_capability);
+    filter_chain_t *p_chain = malloc( size );
     if( !p_chain )
         return NULL;
 
     p_chain->p_this = p_this;
-    vlc_array_init( &p_chain->filters );
-    vlc_array_init( &p_chain->mouses );
-    p_chain->psz_capability = strdup( psz_capability );
-    if( !p_chain->psz_capability )
-    {
-        vlc_array_clear( &p_chain->mouses );
-        vlc_array_clear( &p_chain->filters );
-        free( p_chain );
-        return NULL;
-    }
+    p_chain->last = p_chain->first = NULL;
+    p_chain->length = 0;
+    strcpy( p_chain->psz_capability, psz_capability );
+
     es_format_Init( &p_chain->fmt_in, UNKNOWN_ES, 0 );
     es_format_Init( &p_chain->fmt_out, UNKNOWN_ES, 0 );
     p_chain->b_allow_fmt_out_change = b_allow_fmt_out_change;
@@ -137,9 +141,6 @@ void filter_chain_Delete( filter_chain_t *p_chain )
     es_format_Clean( &p_chain->fmt_in );
     es_format_Clean( &p_chain->fmt_out );
 
-    free( p_chain->psz_capability );
-    vlc_array_clear( &p_chain->mouses );
-    vlc_array_clear( &p_chain->filters );
     free( p_chain );
 }
 /**
@@ -148,12 +149,11 @@ void filter_chain_Delete( filter_chain_t *p_chain )
 void filter_chain_Reset( filter_chain_t *p_chain, const es_format_t *p_fmt_in,
                          const es_format_t *p_fmt_out )
 {
-    while( vlc_array_count( &p_chain->filters ) > 0 )
-    {
-        filter_t *p_filter = vlc_array_item_at_index( &p_chain->filters, 0 );
+    filter_t *p_filter;
 
+    while( (p_filter = &p_chain->first->filter) != NULL )
         filter_chain_DeleteFilterInternal( p_chain, p_filter );
-    }
+
     if( p_fmt_in )
     {
         es_format_Clean( &p_chain->fmt_in );
@@ -203,7 +203,7 @@ int filter_chain_DeleteFilter( filter_chain_t *p_chain, filter_t *p_filter )
 
 int filter_chain_GetLength( filter_chain_t *p_chain )
 {
-    return vlc_array_count( &p_chain->filters );
+    return p_chain->length;
 }
 
 const es_format_t *filter_chain_GetFmtOut( filter_chain_t *p_chain )
@@ -212,12 +212,8 @@ const es_format_t *filter_chain_GetFmtOut( filter_chain_t *p_chain )
     if( p_chain->b_allow_fmt_out_change )
         return &p_chain->fmt_out;
 
-    const int i_count = vlc_array_count( &p_chain->filters );
-    if( i_count > 0 )
-    {
-        filter_t *p_last = vlc_array_item_at_index( &p_chain->filters, i_count - 1 );
-        return &p_last->fmt_out;
-    }
+    if( p_chain->last != NULL )
+        return &p_chain->last->filter.fmt_out;
 
     /* Unless filter_chain_Reset has been called we are doomed */
     return &p_chain->fmt_out;
@@ -225,9 +221,9 @@ const es_format_t *filter_chain_GetFmtOut( filter_chain_t *p_chain )
 
 picture_t *filter_chain_VideoFilter( filter_chain_t *p_chain, picture_t *p_pic )
 {
-    for( int i = 0; i < vlc_array_count( &p_chain->filters ); i++ )
+    for( chained_filter_t *f = p_chain->first; f != NULL; f = f->next )
     {
-        filter_t *p_filter = vlc_array_item_at_index( &p_chain->filters, i );
+        filter_t *p_filter = &f->filter;
 
         p_pic = p_filter->pf_video_filter( p_filter, p_pic );
         if( !p_pic )
@@ -238,9 +234,9 @@ picture_t *filter_chain_VideoFilter( filter_chain_t *p_chain, picture_t *p_pic )
 
 block_t *filter_chain_AudioFilter( filter_chain_t *p_chain, block_t *p_block )
 {
-    for( int i = 0; i < vlc_array_count( &p_chain->filters ); i++ )
+    for( chained_filter_t *f = p_chain->first; f != NULL; f = f->next )
     {
-        filter_t *p_filter = vlc_array_item_at_index( &p_chain->filters, i );
+        filter_t *p_filter = &f->filter;
 
         p_block = p_filter->pf_audio_filter( p_filter, p_block );
         if( !p_block )
@@ -252,10 +248,9 @@ block_t *filter_chain_AudioFilter( filter_chain_t *p_chain, block_t *p_block )
 void filter_chain_SubFilter( filter_chain_t *p_chain,
                              mtime_t display_date )
 {
-    for( int i = 0; i < vlc_array_count( &p_chain->filters ); i++ )
+    for( chained_filter_t *f = p_chain->first; f != NULL; f = f->next )
     {
-        filter_t *p_filter = vlc_array_item_at_index( &p_chain->filters, i );
-
+        filter_t *p_filter = &f->filter;
         subpicture_t *p_subpic = p_filter->pf_sub_filter( p_filter, display_date );
         /* XXX I find that spu_t cast ugly */
         if( p_subpic )
@@ -267,10 +262,10 @@ int filter_chain_MouseFilter( filter_chain_t *p_chain, vlc_mouse_t *p_dst, const
 {
     vlc_mouse_t current = *p_src;
 
-    for( int i = vlc_array_count( &p_chain->filters ) - 1; i >= 0; i-- )
+    for( chained_filter_t *f = p_chain->first; f != NULL; f = f->next )
     {
-        filter_t *p_filter = vlc_array_item_at_index( &p_chain->filters, i );
-        vlc_mouse_t *p_mouse = vlc_array_item_at_index( &p_chain->mouses, i );
+        filter_t *p_filter = &f->filter;
+        vlc_mouse_t *p_mouse = f->mouse;
 
         if( p_filter->pf_mouse && p_mouse )
         {
@@ -296,22 +291,20 @@ static filter_t *filter_chain_AppendFilterInternal( filter_chain_t *p_chain,
                                                     const es_format_t *p_fmt_in,
                                                     const es_format_t *p_fmt_out )
 {
-    filter_t *p_filter = vlc_custom_create( p_chain->p_this, sizeof(*p_filter),
-                                            VLC_OBJECT_GENERIC, "filter" );
+    chained_filter_t *p_chained =
+        vlc_custom_create( p_chain->p_this, sizeof(*p_chained),
+                           VLC_OBJECT_GENERIC, "filter" );
+    filter_t *p_filter = &p_chained->filter;
     if( !p_filter )
         return NULL;
     vlc_object_attach( p_filter, p_chain->p_this );
 
     if( !p_fmt_in )
     {
-        p_fmt_in = &p_chain->fmt_in;
-
-        const int i_count = vlc_array_count( &p_chain->filters );
-        if( i_count > 0 )
-        {
-            filter_t *p_last = vlc_array_item_at_index( &p_chain->filters, i_count - 1 );
-            p_fmt_in = &p_last->fmt_out;
-        }
+        if( p_chain->last != NULL )
+            p_fmt_in = &p_chain->last->filter.fmt_out;
+        else
+            p_fmt_in = &p_chain->fmt_in;
     }
 
     if( !p_fmt_out )
@@ -336,15 +329,25 @@ static filter_t *filter_chain_AppendFilterInternal( filter_chain_t *p_chain,
         es_format_Copy( &p_chain->fmt_out, &p_filter->fmt_out );
     }
 
-    if( AllocatorInit( &p_chain->allocator, p_filter ) )
+    if( AllocatorInit( &p_chain->allocator, p_chained ) )
         goto error;
 
-    vlc_array_append( &p_chain->filters, p_filter );
+    if( p_chain->last == NULL )
+    {
+        assert( p_chain->first == NULL );
+        p_chain->first = p_chained;
+    }
+    else
+        p_chain->last->next = p_chained;
+    p_chained->prev = p_chain->last;
+    p_chain->last = p_chained;
+    p_chained->next = NULL;
+    p_chain->length++;
 
     vlc_mouse_t *p_mouse = malloc( sizeof(*p_mouse) );
     if( p_mouse )
         vlc_mouse_Init( p_mouse );
-    vlc_array_append( &p_chain->mouses, p_mouse );
+    p_chained->mouse = p_mouse;
 
     msg_Dbg( p_chain->p_this, "Filter '%s' (%p) appended to chain",
              psz_name ? psz_name : module_get_name(p_filter->p_module, false),
@@ -407,36 +410,40 @@ static int filter_chain_AppendFromStringInternal( filter_chain_t *p_chain,
 static int filter_chain_DeleteFilterInternal( filter_chain_t *p_chain,
                                               filter_t *p_filter )
 {
-    const int i_filter_idx = vlc_array_index_of_item( &p_chain->filters, p_filter );
-    if( i_filter_idx < 0 )
+    chained_filter_t *p_chained = chained( p_filter );
+
+    /* Remove it from the chain */
+    if( p_chained->prev != NULL )
+        p_chained->prev->next = p_chained->next;
+    else
     {
-        /* Oops, filter wasn't found
-         * FIXME shoulnd't it be an assert instead ? */
-        msg_Err( p_chain->p_this,
-                 "Couldn't find filter %p when trying to remove it from chain",
-                 p_filter );
-        return VLC_EGENERIC;
+        assert( p_chained == p_chain->first );
+        p_chain->first = p_chained->next;
     }
 
-    /* Remove it from the chain */
-    vlc_array_remove( &p_chain->filters, i_filter_idx );
+    if( p_chained->next != NULL )
+        p_chained->next->prev = p_chained->prev;
+    else
+    {
+        assert( p_chained == p_chain->last );
+        p_chain->last = p_chained->prev;
+    }
+    p_chain->length--;
 
     msg_Dbg( p_chain->p_this, "Filter %p removed from chain", p_filter );
 
     /* Destroy the filter object */
-    if( IsInternalVideoAllocator( p_filter ) )
-        AllocatorClean( &internal_video_allocator, p_filter );
+    if( IsInternalVideoAllocator( p_chained ) )
+        AllocatorClean( &internal_video_allocator, p_chained );
     else
-        AllocatorClean( &p_chain->allocator, p_filter );
+        AllocatorClean( &p_chain->allocator, p_chained );
 
     vlc_object_detach( p_filter );
     if( p_filter->p_module )
         module_unneed( p_filter, p_filter->p_module );
+    free( p_chained->mouse );
     vlc_object_release( p_filter );
 
-    vlc_mouse_t *p_mouse = vlc_array_item_at_index( &p_chain->mouses, i_filter_idx );
-    free( p_mouse );
-    vlc_array_remove( &p_chain->mouses, i_filter_idx );
 
     /* FIXME: check fmt_in/fmt_out consitency */
     return VLC_SUCCESS;
@@ -455,31 +462,32 @@ static int UpdateVideoBufferFunctions( filter_chain_t *p_chain )
      * filter without having to worry about the parent's picture
      * heap format.
      */
-    const int i_count = vlc_array_count( &p_chain->filters );
-    for( int i = 0; i < i_count - 1; i++ )
-    {
-        filter_t *p_filter = vlc_array_item_at_index( &p_chain->filters, i );
+    /* FIXME: we should only update the last and penultimate filters */
+    chained_filter_t *f;
 
-        if( !IsInternalVideoAllocator( p_filter ) )
+    for( f = p_chain->first; f != p_chain->last; f = f->next )
+    {
+        if( !IsInternalVideoAllocator( f ) )
         {
-            AllocatorClean( &p_chain->allocator, p_filter );
+            AllocatorClean( &p_chain->allocator, f );
 
-            AllocatorInit( &internal_video_allocator, p_filter );
+            AllocatorInit( &internal_video_allocator, f );
         }
     }
-    if( i_count >= 1 )
+
+    if( f != NULL )
     {
-        filter_t * p_filter = vlc_array_item_at_index( &p_chain->filters, i_count - 1 );
-        if( IsInternalVideoAllocator( p_filter ) )
+        if( IsInternalVideoAllocator( f ) )
         {
-            AllocatorClean( &internal_video_allocator, p_filter );
+            AllocatorClean( &internal_video_allocator, f );
 
-            if( AllocatorInit( &p_chain->allocator, p_filter ) )
+            if( AllocatorInit( &p_chain->allocator, f ) )
                 return VLC_EGENERIC;
         }
     }
     return VLC_SUCCESS;
 }
+
 /**
  * This function should be called after every filter chain change
  */
@@ -522,21 +530,25 @@ static void InternalVideoClean( filter_t *p_filter )
     p_filter->pf_vout_buffer_new = NULL;
     p_filter->pf_vout_buffer_del = NULL;
 }
-static bool IsInternalVideoAllocator( filter_t *p_filter )
+
+static bool IsInternalVideoAllocator( chained_filter_t *p_filter )
 {
-    return p_filter->pf_vout_buffer_new == VideoBufferNew;
+    return p_filter->filter.pf_vout_buffer_new == VideoBufferNew;
 }
 
 /* */
-static int AllocatorInit( const filter_chain_allocator_t *p_alloc, filter_t *p_filter )
+static int AllocatorInit( const filter_chain_allocator_t *p_alloc,
+                          chained_filter_t *p_filter )
 {
     if( p_alloc->pf_init )
-        return p_alloc->pf_init( p_filter, p_alloc->p_data );
+        return p_alloc->pf_init( &p_filter->filter, p_alloc->p_data );
     return VLC_SUCCESS;
 }
-static void AllocatorClean( const filter_chain_allocator_t *p_alloc, filter_t *p_filter )
+
+static void AllocatorClean( const filter_chain_allocator_t *p_alloc,
+                            chained_filter_t *p_filter )
 {
     if( p_alloc->pf_clean )
-        p_alloc->pf_clean( p_filter );
+        p_alloc->pf_clean( &p_filter->filter );
 }