git-log: Add usage string

diff --git a/read-cache.c b/read-cache.c
index ced597318e783ab08b73c88f8b724be51f3b3dec..693273620370e0500bc9ea2adba98a88cafc39cd 100644 (file)
--- a/read-cache.c
+++ b/read-cache.c
@@ -35,8 +35,11 @@ int ce_match_stat(struct cache_entry *ce, struct stat *st)
        switch (ntohl(ce->ce_mode) & S_IFMT) {
        case S_IFREG:
                changed |= !S_ISREG(st->st_mode) ? TYPE_CHANGED : 0;
-               /* We consider only the owner x bit to be relevant for "mode changes" */
-               if (0100 & (ntohl(ce->ce_mode) ^ st->st_mode))
+               /* We consider only the owner x bit to be relevant for
+                * "mode changes"
+                */
+               if (trust_executable_bit &&
+                   (0100 & (ntohl(ce->ce_mode) ^ st->st_mode)))
                        changed |= MODE_CHANGED;
                break;
        case S_IFLNK:
@@ -83,6 +86,83 @@ int ce_match_stat(struct cache_entry *ce, struct stat *st)
        return changed;
 }
 
+static int ce_compare_data(struct cache_entry *ce, struct stat *st)
+{
+       int match = -1;
+       int fd = open(ce->name, O_RDONLY);
+
+       if (fd >= 0) {
+               unsigned char sha1[20];
+               if (!index_fd(sha1, fd, st, 0, NULL))
+                       match = memcmp(sha1, ce->sha1, 20);
+               close(fd);
+       }
+       return match;
+}
+
+static int ce_compare_link(struct cache_entry *ce, unsigned long expected_size)
+{
+       int match = -1;
+       char *target;
+       void *buffer;
+       unsigned long size;
+       char type[10];
+       int len;
+
+       target = xmalloc(expected_size);
+       len = readlink(ce->name, target, expected_size);
+       if (len != expected_size) {
+               free(target);
+               return -1;
+       }
+       buffer = read_sha1_file(ce->sha1, type, &size);
+       if (!buffer) {
+               free(target);
+               return -1;
+       }
+       if (size == expected_size)
+               match = memcmp(buffer, target, size);
+       free(buffer);
+       free(target);
+       return match;
+}
+
+int ce_modified(struct cache_entry *ce, struct stat *st)
+{
+       int changed;
+       changed = ce_match_stat(ce, st);
+       if (!changed)
+               return 0;
+
+       /*
+        * If the mode or type has changed, there's no point in trying
+        * to refresh the entry - it's not going to match
+        */
+       if (changed & (MODE_CHANGED | TYPE_CHANGED))
+               return changed;
+
+       /* Immediately after read-tree or update-index --cacheinfo,
+        * the length field is zero.  For other cases the ce_size
+        * should match the SHA1 recorded in the index entry.
+        */
+       if ((changed & DATA_CHANGED) && ce->ce_size != htonl(0))
+               return changed;
+
+       switch (st->st_mode & S_IFMT) {
+       case S_IFREG:
+               if (ce_compare_data(ce, st))
+                       return changed | DATA_CHANGED;
+               break;
+       case S_IFLNK:
+               if (ce_compare_link(ce, st->st_size))
+                       return changed | DATA_CHANGED;
+               break;
+       default:
+               return changed | TYPE_CHANGED;
+       }
+       return 0;
+}
+
 int base_name_compare(const char *name1, int len1, int mode1,
                      const char *name2, int len2, int mode2)
 {
@@ -155,7 +235,7 @@ int remove_cache_entry_at(int pos)
        return 1;
 }
 
-int remove_file_from_cache(char *path)
+int remove_file_from_cache(const char *path)
 {
        int pos = cache_name_pos(path, strlen(path));
        if (pos < 0)
@@ -315,7 +395,7 @@ int add_cache_entry(struct cache_entry *ce, int option)
        int skip_df_check = option & ADD_CACHE_SKIP_DFCHECK;
        pos = cache_name_pos(ce->name, ntohs(ce->ce_flags));
 
-       /* existing match? Just replace it */
+       /* existing match? Just replace it. */
        if (pos >= 0) {
                active_cache_changed = 1;
                active_cache[pos] = ce;
@@ -338,7 +418,8 @@ int add_cache_entry(struct cache_entry *ce, int option)
        if (!ok_to_add)
                return -1;
 
-       if (!skip_df_check && check_file_directory_conflict(ce, pos, ok_to_replace)) {
+       if (!skip_df_check &&
+           check_file_directory_conflict(ce, pos, ok_to_replace)) {
                if (!ok_to_replace)
                        return -1;
                pos = cache_name_pos(ce->name, ntohs(ce->ce_flags));
@@ -387,11 +468,15 @@ int read_cache(void)
 
        errno = EBUSY;
        if (active_cache)
-               return error("more than one cachefile");
+               return active_nr;
+
        errno = ENOENT;
        fd = open(get_index_file(), O_RDONLY);
-       if (fd < 0)
-               return (errno == ENOENT) ? 0 : error("open failed");
+       if (fd < 0) {
+               if (errno == ENOENT)
+                       return 0;
+               die("index file open failed (%s)", strerror(errno));
+       }
 
        size = 0; // avoid gcc warning
        map = MAP_FAILED;
@@ -403,7 +488,7 @@ int read_cache(void)
        }
        close(fd);
        if (map == MAP_FAILED)
-               return error("mmap failed");
+               die("index file mmap failed (%s)", strerror(errno));
 
        hdr = map;
        if (verify_hdr(hdr, size) < 0)
@@ -424,7 +509,7 @@ int read_cache(void)
 unmap:
        munmap(map, size);
        errno = EINVAL;
-       return error("verify header failed");
+       die("index file corrupt");
 }
 
 #define WRITE_BUFFER_SIZE 8192
@@ -462,6 +547,13 @@ static int ce_flush(SHA_CTX *context, int fd)
                SHA1_Update(context, write_buffer, left);
        }
 
+       /* Flush first if not enough space for SHA1 signature */
+       if (left + 20 > WRITE_BUFFER_SIZE) {
+               if (write(fd, write_buffer, left) != left)
+                       return -1;
+               left = 0;
+       }
+
        /* Append the SHA1 signature at the end */
        SHA1_Final(write_buffer + left, context);
        left += 20;