add "trackmemusage" property to use in improved _XftFontUncacheGlyph

The linear search used for randomly selecting a glyph to discard is
inefficient.  This commit provides for a doubly-linked list which
could be maintained by the library to quickly discard the least
recently used glyph.

Signed-off-by: Thomas E. Dickey <dickey@invisible-island.net>

1 files changed, 26 insertions, 5 deletions

diff --git a/src/xftint.h b/src/xftint.h
index f35823f..3687d6f 100644
--- a/src/xftint.h
+++ b/src/xftint.h
@@ -88,6 +88,16 @@ typedef struct _XftGlyph {
 } XftGlyph;
 
 /*
+ * If the "trackmemusage" option is set, glyphs are managed via a doubly-linked
+ * list.  To save space, the links are just array indices.
+ */
+typedef struct _XftGlyphUsage {
+    XftGlyph        contents;
+    FT_UInt	    newer;
+    FT_UInt	    older;
+} XftGlyphUsage;
+
+/*
  * A hash table translates Unicode values into glyph indices
  */
 typedef struct _XftUcsHash {
@@ -181,6 +191,8 @@ typedef struct _XftFontInt {
      */
     unsigned long	glyph_memory;
     unsigned long	max_glyph_memory;
+    unsigned            sizeof_glyph;	/* sizeof(XftGlyph) or XftGlyphUsage */
+    FcBool		track_mem_usage;   /* Use XftGlyphUsage */
     FcBool		use_free_glyphs;   /* Use XRenderFreeGlyphs */
 } XftFontInt;
 
@@ -250,6 +262,7 @@ typedef struct _XftDisplayInfo {
     XRenderPictFormat	    *solidFormat;
     unsigned long	    glyph_memory;
     unsigned long	    max_glyph_memory;
+    FcBool		    track_mem_usage;
     FcBool		    use_free_glyphs;
     int			    num_unref_fonts;
     int			    max_unref_fonts;
@@ -273,6 +286,9 @@ typedef struct _XftDisplayInfo {
 
 extern XftDisplayInfo	*_XftDisplayInfo;
 
+/*
+ * Bits in $XFT_DEBUG, which can be combined.
+ */
 #define XFT_DBG_OPEN	1
 #define XFT_DBG_OPENV	2
 #define XFT_DBG_RENDER	4
@@ -284,11 +300,16 @@ extern XftDisplayInfo	*_XftDisplayInfo;
 #define XFT_DBG_CACHEV	256
 #define XFT_DBG_MEMORY	512
 
-#define XFT_MEM_DRAW	0
-#define XFT_MEM_FONT	1
-#define XFT_MEM_FILE	2
-#define XFT_MEM_GLYPH	3
-#define XFT_MEM_NUM	4
+/*
+ * Categories for memory allocation.
+ */
+typedef enum {
+    XFT_MEM_DRAW
+    , XFT_MEM_FONT
+    , XFT_MEM_FILE
+    , XFT_MEM_GLYPH
+    , XFT_MEM_NUM
+} XFT_MEM_KIND;
 
 #define AllocTypedArray(n,type)         malloc ((size_t)(n) * sizeof (type))
 #define AllocUIntArray(n)               AllocTypedArray(n, FT_UInt)