[PATCH] Consolidate the error handling

[git.git] / read-cache.c

diff --git a/read-cache.c b/read-cache.c
index 91b2628..d8b383f 100644 (file)
--- a/read-cache.c
+++ b/read-cache.c
@@ -3,6 +3,7 @@
  *
  * Copyright (C) Linus Torvalds, 2005
  */
+#include <stdarg.h>
 #include "cache.h"
 
 const char *sha1_file_directory = NULL;
@@ -11,10 +12,38 @@ unsigned int active_nr = 0, active_alloc = 0;
 
 void usage(const char *err)
 {
-       fprintf(stderr, "read-tree: %s\n", err);
+       fprintf(stderr, "usage: %s\n", err);
        exit(1);
 }
 
+static void report(const char *prefix, const char *err, va_list params)
+{
+       fputs(prefix, stderr);
+       vfprintf(stderr, err, params);
+       fputs("\n", stderr);
+}
+
+void die(const char *err, ...)
+{
+       va_list params;
+
+       va_start(params, err);
+       report("fatal: ", err, params);
+       va_end(params);
+       exit(1);
+}
+
+int error(const char *err, ...)
+{
+       va_list params;
+
+       va_start(params, err);
+       report("error: ", err, params);
+       va_end(params);
+       return -1;
+}
+
+
 static unsigned hexval(char c)
 {
        if (c >= '0' && c <= '9')
@@ -59,7 +88,7 @@ char * sha1_to_hex(const unsigned char *sha1)
  * careful about using it. Do a "strdup()" if you need to save the
  * filename.
  */
-char *sha1_file_name(unsigned char *sha1)
+char *sha1_file_name(const unsigned char *sha1)
 {
        int i;
        static char *name, *base;
@@ -95,7 +124,7 @@ int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size)
        return memcmp(sha1, real_sha1, 20) ? -1 : 0;
 }
 
-void *map_sha1_file(unsigned char *sha1, unsigned long *size)
+void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 {
        char *filename = sha1_file_name(sha1);
        int fd = open(filename, O_RDONLY);
@@ -154,7 +183,7 @@ void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned l
        return buf;
 }
 
-void * read_sha1_file(unsigned char *sha1, char *type, unsigned long *size)
+void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
 {
        unsigned long mapsize;
        void *map, *buf;
@@ -204,34 +233,53 @@ int write_sha1_file(char *buf, unsigned len, unsigned char *returnsha1)
        return 0;
 }
 
-int write_sha1_buffer(unsigned char *sha1, void *buf, unsigned int size)
+int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int size)
 {
        char *filename = sha1_file_name(sha1);
        int fd;
 
        fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
-       if (fd < 0)
-               return (errno == EEXIST) ? 0 : -1;
+       if (fd < 0) {
+               void *map;
+
+               if (errno != EEXIST)
+                       return -1;
+#ifndef COLLISION_CHECK
+               fd = open(filename, O_RDONLY);
+               if (fd < 0)
+                       return -1;
+               map = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
+               if (map == MAP_FAILED)
+                       return -1;
+               if (memcmp(buf, map, size))
+                       return error("SHA1 collision detected!"
+                                       " This is bad, bad, BAD!\a\n");
+#endif
+               return 0;
+       }
        write(fd, buf, size);
        close(fd);
        return 0;
 }
 
-static int error(const char * string)
-{
-       fprintf(stderr, "error: %s\n", string);
-       return -1;
-}
-
 int cache_match_stat(struct cache_entry *ce, struct stat *st)
 {
        unsigned int changed = 0;
 
-       if (ce->mtime.sec  != (unsigned int)st->st_mtim.tv_sec ||
-           ce->mtime.nsec != (unsigned int)st->st_mtim.tv_nsec)
+       /* nsec seems unreliable - not all filesystems support it, so
+        * as long as it is in the inode cache you get right nsec
+        * but after it gets flushed, you get zero nsec. */
+       if (ce->mtime.sec  != (unsigned int)st->st_mtim.tv_sec
+#ifdef NSEC
+           || ce->mtime.nsec != (unsigned int)st->st_mtim.tv_nsec
+#endif
+           )
                changed |= MTIME_CHANGED;
-       if (ce->ctime.sec  != (unsigned int)st->st_ctim.tv_sec ||
-           ce->ctime.nsec != (unsigned int)st->st_ctim.tv_nsec)
+       if (ce->ctime.sec  != (unsigned int)st->st_ctim.tv_sec
+#ifdef NSEC
+           || ce->ctime.nsec != (unsigned int)st->st_ctim.tv_nsec
+#endif
+           )
                changed |= CTIME_CHANGED;
        if (ce->st_uid != (unsigned int)st->st_uid ||
            ce->st_gid != (unsigned int)st->st_gid)
@@ -272,39 +320,42 @@ int cache_name_pos(const char *name, int namelen)
                struct cache_entry *ce = active_cache[next];
                int cmp = cache_name_compare(name, namelen, ce->name, ce->namelen);
                if (!cmp)
-                       return -next-1;
+                       return next;
                if (cmp < 0) {
                        last = next;
                        continue;
                }
                first = next+1;
        }
-       return first;
+       return -first-1;
 }
 
 int remove_file_from_cache(char *path)
 {
        int pos = cache_name_pos(path, strlen(path));
-       if (pos < 0) {
-               pos = -pos-1;
+       if (pos >= 0) {
                active_nr--;
                if (pos < active_nr)
-                       memmove(active_cache + pos, active_cache + pos + 1, (active_nr - pos - 1) * sizeof(struct cache_entry *));
+                       memmove(active_cache + pos, active_cache + pos + 1, (active_nr - pos) * sizeof(struct cache_entry *));
        }
        return 0;
 }
 
-int add_cache_entry(struct cache_entry *ce)
+int add_cache_entry(struct cache_entry *ce, int ok_to_add)
 {
        int pos;
 
        pos = cache_name_pos(ce->name, ce->namelen);
 
        /* existing match? Just replace it */
-       if (pos < 0) {
-               active_cache[-pos-1] = ce;
+       if (pos >= 0) {
+               active_cache[pos] = ce;
                return 0;
        }
+       pos = -pos-1;
+
+       if (!ok_to_add)
+               return -1;
 
        /* Make sure the array is big enough .. */
        if (active_nr == active_alloc) {
@@ -355,7 +406,7 @@ int read_cache(void)
                sha1_file_directory = DEFAULT_DB_ENVIRONMENT;
        if (access(sha1_file_directory, X_OK) < 0)
                return error("no access to SHA1 file directory");
-       fd = open(".dircache/index", O_RDONLY);
+       fd = open(".git/index", O_RDONLY);
        if (fd < 0)
                return (errno == ENOENT) ? 0 : error("open failed");