Attachment 32209 Details for Bug 25535 – [patch] Fix cache aging for fonts on FAT

[patch] [patch] Fix cache aging for fonts on FAT

0001-Fix-cache-aging-for-fonts-on-FAT-filesystem-under-Li.patch (text/plain), 6.74 KB, created by Mikhail Gusarov on 2009-12-20 10:11:21 UTC

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Creator: Mikhail Gusarov

Created: 2009-12-20 10:11:21 UTC

Size: 6.74 KB

patch

obsolete

>From 2d915cc276545beddca15761b16a0bcddb59480f Mon Sep 17 00:00:00 2001
>From: Mikhail Gusarov <dottedmag@dottedmag.net>
>Date: Mon, 21 Dec 2009 00:03:06 +0600
>Subject: [PATCH] Fix cache aging for fonts on FAT filesystem under Linux
>
>Windows does not update mtime of directory on FAT filesystem when
>file is added to it or removed from it. Fontconfig uses mtime of
>directory to check cache file aging and hence fails to detect
>newly added or recently removed files.
>
>This patch detects FAT filesystem (currently implemented for
>Linux) and adds generating checksum of directory entries instead
>of using mtime which guarantees proper cache rebuild.
>
>For non-FAT filesystems this patch adds single syscall per directory
>which is negligeable overhead.
>
>This fixes bug https://bugs.freedesktop.org/show_bug.cgi?id=25535
>
>Signed-off-by: Mikhail Gusarov <dottedmag@dottedmag.net>
>---
> src/fccache.c |  137 ++++++++++++++++++++++++++++++++++++++++++++++++++++++---
> src/fcdir.c   |    2 +-
> src/fcint.h   |    9 +++-
> 3 files changed, 139 insertions(+), 9 deletions(-)
>
>diff --git a/src/fccache.c b/src/fccache.c
>index 69e1a6b..79299a9 100644
>--- a/src/fccache.c
>+++ b/src/fccache.c
>@@ -36,6 +36,11 @@
> #  define _WIN32_WINNT 0x0500
> #  include <windows.h>
> #endif
>+/* For FcFsMtimeBroken */
>+#if defined(linux)
>+#  include <sys/vfs.h>
>+#  include <linux/magic.h>
>+#endif
> 
> #ifndef O_BINARY
> #define O_BINARY 0
>@@ -133,6 +138,124 @@ FcStat (const char *file, struct stat *statb)
> }
> #endif
> 
>+/*
>+ * Checking for FAT filesystem which broken mtime handling. There is no
>+ * cross-platform filesystem type query call, so resort to OS-specific calls.
>+ */
>+#if defined(linux)
>+static FcBool
>+FcFsMtimeBroken (const char *file)
>+{
>+    int ret;
>+    struct statfs fs_stat;
>+
>+    if (FcDebug () & FC_DBG_CACHE)
>+	printf ("FcFsMtimeBroken %s\n", file);
>+
>+    ret = statfs (file, &fs_stat);
>+    if (ret == -1)
>+	return FcFalse;
>+
>+    if (FcDebug () & FC_DBG_CACHE)
>+	printf ("FcFsMtimeBroken f_type %ld MSDOS_SUPER_MAGIC %d\n",
>+	        fs_stat.f_type, MSDOS_SUPER_MAGIC);
>+
>+    if (fs_stat.f_type == MSDOS_SUPER_MAGIC)
>+	return FcTrue;
>+
>+    return FcFalse;
>+}
>+#endif
>+
>+/*
>+ * This is to be enabled on all systems which support checking for FAT fs, not
>+ * just Linux
>+ */
>+#if defined(linux)
>+
>+/* Adler-32 checksum implementation */
>+struct Adler32 {
>+    int a;
>+    int b;
>+};
>+
>+static void
>+Adler32Init (struct Adler32 *ctx)
>+{
>+    ctx->a = 1;
>+    ctx->b = 0;
>+}
>+
>+static void
>+Adler32Update (struct Adler32 *ctx, const char *data, int data_len)
>+{
>+    while (data_len--)
>+    {
>+	ctx->a = (ctx->a + *data++) % 65521;
>+	ctx->b = (ctx->b + ctx->a) % 65521;
>+    }
>+}
>+
>+static int
>+Adler32Finish (struct Adler32 *ctx)
>+{
>+    return ctx->a + (ctx->b << 16);
>+}
>+
>+/* dirent.d_type could be relied upon on FAT filesystem */
>+static FcBool
>+FcDirChecksumScandirFilter(const struct dirent *entry)
>+{
>+    return entry->d_type != DT_DIR;
>+}
>+
>+static int
>+FcDirChecksum (const char *dir)
>+{
>+    struct Adler32 ctx;
>+    struct dirent **files;
>+    int n;
>+    int checksum;
>+
>+    Adler32Init (&ctx);
>+
>+    n = scandir (dir, &files, &FcDirChecksumScandirFilter, alphasort);
>+    if (n == -1)
>+        return -1;
>+
>+    while (n--)
>+    {
>+        Adler32Update (&ctx, files[n]->d_name, strlen(files[n]->d_name) + 1);
>+        Adler32Update (&ctx, (char *)&files[n]->d_type, sizeof(files[n]->d_type));
>+    }
>+
>+    checksum = Adler32Finish (&ctx);
>+
>+    /* Whoops. Adler-32 may be -1 as well. "Correct" it. */
>+    return checksum == -1 ? 0 : checksum;
>+}
>+
>+int
>+FcStatChecksum (const char *file, struct stat *statb)
>+{
>+    int ret;
>+
>+    ret = FcStat (file, statb);
>+    if (ret == -1)
>+        return -1;
>+
>+    if (FcFsMtimeBroken (file))
>+    {
>+        int checksum = FcDirChecksum (file);
>+        if (checksum == -1)
>+            return -1;
>+        statb->st_mtime = checksum;
>+    }
>+
>+    return 0;
>+}
>+#endif
>+
> static const char bin2hex[] = { '0', '1', '2', '3',
> 				'4', '5', '6', '7',
> 				'8', '9', 'a', 'b',
>@@ -233,7 +356,7 @@ FcDirCacheProcess (FcConfig *config, const FcChar8 *dir,
>     struct stat file_stat, dir_stat;
>     FcBool	ret = FcFalse;
> 
>-    if (FcStat ((char *) dir, &dir_stat) < 0)
>+    if (FcStatChecksum ((char *) dir, &dir_stat) < 0)
>         return FcFalse;
> 
>     FcDirCacheBasename (dir, cache_base);
>@@ -515,14 +638,14 @@ FcCacheTimeValid (FcCache *cache, struct stat *dir_stat)
> 
>     if (!dir_stat)
>     {
>-	if (FcStat ((const char *) FcCacheDir (cache), &dir_static) < 0)
>+	if (FcStatChecksum ((const char *) FcCacheDir (cache), &dir_static) < 0)
> 	    return FcFalse;
> 	dir_stat = &dir_static;
>     }
>     if (FcDebug () & FC_DBG_CACHE)
>-	printf ("FcCacheTimeValid dir \"%s\" cache time %d dir time %d\n",
>-		FcCacheDir (cache), cache->mtime, (int) dir_stat->st_mtime);
>-    return cache->mtime == (int) dir_stat->st_mtime;
>+	printf ("FcCacheTimeValid dir \"%s\" cache checksum %d dir checksum %d\n",
>+		FcCacheDir (cache), cache->checksum, (int) dir_stat->st_mtime);
>+    return cache->checksum == (int) dir_stat->st_mtime;
> }
> 
> /*
>@@ -683,7 +806,7 @@ FcDirCacheValidateHelper (int fd, struct stat *fd_stat, struct stat *dir_stat, v
> 	ret = FcFalse;
>     else if (fd_stat->st_size != c.size)
> 	ret = FcFalse;
>-    else if (c.mtime != (int) dir_stat->st_mtime)
>+    else if (c.checksum != (int) dir_stat->st_mtime)
> 	ret = FcFalse;
>     return ret;
> }
>@@ -760,7 +883,7 @@ FcDirCacheBuild (FcFontSet *set, const FcChar8 *dir, struct stat *dir_stat, FcSt
>     cache->magic = FC_CACHE_MAGIC_ALLOC;
>     cache->version = FC_CACHE_CONTENT_VERSION;
>     cache->size = serialize->size;
>-    cache->mtime = (int) dir_stat->st_mtime;
>+    cache->checksum = (int) dir_stat->st_mtime;
> 
>     /*
>      * Serialize directory name
>diff --git a/src/fcdir.c b/src/fcdir.c
>index f927c0b..b0d626b 100644
>--- a/src/fcdir.c
>+++ b/src/fcdir.c
>@@ -243,7 +243,7 @@ FcDirCacheScan (const FcChar8 *dir, FcConfig *config)
>     if (FcDebug () & FC_DBG_FONTSET)
> 	printf ("cache scan dir %s\n", dir);
> 
>-    if (FcStat ((char *) dir, &dir_stat) < 0)
>+    if (FcStatChecksum ((char *) dir, &dir_stat) < 0)
>     {
> 	if (errno != ENOENT)
> 	    ret = FcFalse;
>diff --git a/src/fcint.h b/src/fcint.h
>index 233b4c3..cc0d0dd 100644
>--- a/src/fcint.h
>+++ b/src/fcint.h
>@@ -333,7 +333,7 @@ struct _FcCache {
>     intptr_t	dirs;		    /* offset to subdirs */
>     int		dirs_count;	    /* number of subdir strings */
>     intptr_t	set;		    /* offset to font set */
>-    int		mtime;		    /* low bits of directory mtime */
>+    int		checksum;		    /* checksum of directory state */
> };
> 
> #undef FcCacheDir
>@@ -539,6 +539,13 @@ FcStat (const char *file, struct stat *statb);
> #define FcStat stat
> #endif
> 
>+#ifdef linux
>+FcPrivate int
>+FcStatChecksum (const char *file, struct stat *statb);
>+#else
>+#define FcStatChecksum FcStat
>+#endif
>+
> /* fccfg.c */
> 
> FcPrivate FcExpr *
>-- 
>1.6.3.3
>

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Attachments on bug 25535: 32209 | 43671 | 43672 | 60763 | 60764 | 61532 | 61533 | 61534

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