[gs-cvs] rev 7119 - trunk/gs/src

[tor at ghostscript.com]

Author: tor
Date: 2006-10-24 05:22:14 -0700 (Tue, 24 Oct 2006)
New Revision: 7119

Modified:
   trunk/gs/src/gxccman.c
   trunk/gs/src/gxfcache.h
Log:
A conditionally compiled mechanism to allow cached characters
to be locked out from eviction. A cached character has a reference
count, which if non-zero will prevent the cache slot to be evicted.

This is needed for the GSLite API.



Modified: trunk/gs/src/gxccman.c
===================================================================
--- trunk/gs/src/gxccman.c	2006-10-23 11:17:11 UTC (rev 7118)
+++ trunk/gs/src/gxccman.c	2006-10-24 12:22:14 UTC (rev 7119)
@@ -148,7 +148,11 @@
     for (chi = 0; chi <= cmax;) {
 	cached_char *cc = dir->ccache.table[chi];
 
-	if (cc != 0 && (*proc) (dir->memory, cc, proc_data)) {
+	if (cc != 0 &&
+#ifdef GSLITE
+		!cc->dont_evict &&
+#endif
+		(*proc) (dir->memory, cc, proc_data)) {
 	    hash_remove_cached_char(dir, chi);
 	    gx_free_cached_char(dir, cc);
 	} else
@@ -1024,7 +1028,14 @@
 	) {
 	if (cch == 0) {		/* Not enough room to allocate in this chunk. */
 	    return 0;
-	} {			/* Free the character */
+	}
+#ifdef GSLITE
+	/* We shouldn't free because it's used. */
+	if (cc->dont_evict) {
+	    return 0;
+	}
+#endif
+	else {			/* Free the character */
 	    cached_fm_pair *pair = cc_pair(cc);
 
 	    if (pair != 0) {
@@ -1034,12 +1045,19 @@
 		    chi++;
 		hash_remove_cached_char(dir, chi);
 	    }
+
 	    gx_free_cached_char(dir, cc);
 	}
     }
+
+#ifdef GSLITE
+    cc->dont_evict = 0;
+#endif
+
     cc->chunk = cck;
     cc->loc = (byte *) cc - cck->data;
     return cc;
+
 #undef cc
 }
 
@@ -1080,3 +1098,18 @@
     if_debug2('K', "[K]shortening creates free block 0x%lx(%u)\n",
 	      (ulong) ((byte *) cc + cc->head.size), diff);
 }
+
+#ifdef GSLITE
+
+void gx_retain_cached_char(cached_char *cc)
+{
+    cc->dont_evict ++;
+}
+
+void gx_release_cached_char(cached_char *cc)
+{
+    cc->dont_evict --;
+}
+
+#endif
+

Modified: trunk/gs/src/gxfcache.h
===================================================================
--- trunk/gs/src/gxfcache.h	2006-10-23 11:17:11 UTC (rev 7118)
+++ trunk/gs/src/gxfcache.h	2006-10-24 12:22:14 UTC (rev 7119)
@@ -169,6 +169,21 @@
     uint pair_index;		/* index of pair in mdata */
     gs_fixed_point subpix_origin; /* glyph origin offset modulo pixel */
 
+#ifdef GSLITE
+    /* GSLite API needs to be able to lock a cache entry from being
+       evicted. We do this by counting how many times the GSLite user
+       has "retained" the slot. The initial value of this is zero.
+       For normal ghostscript operation it will never be changed,
+       so it has no effect.
+
+       This is an ugly and ill conceived hack that was implemented
+       at the behest of a large customer. It is guarded by this ifdef
+       for a reason. We do not want our own code to depend on
+       this functionality.
+     */
+    int dont_evict;
+#endif
+
     /* The rest of the structure is the 'value'. */
     /* gx_cached_bits_common has width, height, raster, */
     /* shift (not used here), id. */
@@ -222,6 +237,11 @@
 #define chars_head_index(glyph, pair)\
   ((uint)(glyph) * 59 + (pair)->hash * 73)	/* scramble it a bit */
 
+#ifdef GSLITE
+void gx_retain_cached_char(cached_char *cc);
+void gx_release_cached_char(cached_char *cc);
+#endif
+
 /* ------ Character cache ------ */
 
 /*