[PATCH] Fix +x-related show-diff false positives

[git.git] / show-diff.c

diff --git a/show-diff.c b/show-diff.c
index a15e9b4..8a66e59 100644 (file)
--- a/show-diff.c
+++ b/show-diff.c
@@ -5,13 +5,68 @@
  */
 #include "cache.h"
 
-static void show_differences(char *name,
-       void *old_contents, unsigned long long old_size)
+static char *diff_cmd = "diff -L '%s' -u -N  - '%s'";
+
+/* Help to copy the thing properly quoted for the shell safety.
+ * any single quote is replaced with '\'', and the caller is
+ * expected to enclose the result within a single quote pair.
+ *
+ * E.g.
+ *  original     sq_expand     result
+ *  name     ==> name      ==> 'name'
+ *  a b      ==> a b       ==> 'a b'
+ *  a'b      ==> a'\''b    ==> 'a'\''b'
+ *
+ * NOTE! The returned memory belongs to this function so
+ * do not free it.
+ */
+static char *sq_expand(char *src)
+{
+       static char *buf = NULL;
+       static int buf_size = -1;
+       int cnt, c;
+       char *cp;
+
+       /* count single quote characters */ 
+       for (cnt = 0, cp = src; *cp; cnt++, cp++)
+               if (*cp == '\'')
+                       cnt += 3;
+
+       if (buf_size < cnt) {
+               free(buf);
+               buf_size = cnt;
+               buf = malloc(cnt);
+       }
+
+       cp = buf;
+       while ((c = *src++)) {
+               if (c != '\'')
+                       *cp++ = c;
+               else {
+                       cp = strcpy(cp, "'\\''");
+                       cp += 4;
+               }
+       }
+       *cp = 0;
+       return buf;
+}
+
+static void show_differences(char *name, void *old_contents,
+                            unsigned long long old_size)
 {
-       static char cmd[1000];
        FILE *f;
+       static char *cmd = NULL;
+       static int cmd_size = -1;
+
+       char *name_sq = sq_expand(name);
+       int cmd_required_length = strlen(name_sq) * 2 + strlen(diff_cmd);
 
-       snprintf(cmd, sizeof(cmd), "diff -L %s -u -N  - %s", name, name);
+       if (cmd_size < cmd_required_length) {
+               free(cmd);
+               cmd_size = cmd_required_length;
+               cmd = malloc(cmd_required_length);
+       }
+       snprintf(cmd, cmd_size, diff_cmd, name_sq, name_sq);
        f = popen(cmd, "w");
        if (old_size)
                fwrite(old_contents, old_size, 1, f);
@@ -55,20 +110,46 @@ static void show_diff_empty(struct cache_entry *ce)
        }
 }
 
+static const char *show_diff_usage = "show-diff [-q] [-s] [-z] [paths...]";
+
+static int matches_pathspec(struct cache_entry *ce, char **spec, int cnt)
+{
+       int i;
+       int namelen = ce_namelen(ce);
+       for (i = 0; i < cnt; i++) {
+               int speclen = strlen(spec[i]);
+               if (! strncmp(spec[i], ce->name, speclen) &&
+                   speclen <= namelen &&
+                   (ce->name[speclen] == 0 ||
+                    ce->name[speclen] == '/'))
+                       return 1;
+       }
+       return 0;
+}
+
 int main(int argc, char **argv)
 {
        int silent = 0;
+       int silent_on_nonexisting_files = 0;
+       int machine_readable = 0;
        int entries = read_cache();
        int i;
 
-       while (argc-- > 1) {
-               if (!strcmp(argv[1], "-s")) {
-                       silent = 1;
-                       continue;
-               }
-               usage("show-diff [-s]");
+       while (1 < argc && argv[1][0] == '-') {
+               if (!strcmp(argv[1], "-s"))
+                       silent_on_nonexisting_files = silent = 1;
+               else if (!strcmp(argv[1], "-q"))
+                       silent_on_nonexisting_files = 1;
+               else if (!strcmp(argv[1], "-z"))
+                       machine_readable = 1;
+               else
+                       usage(show_diff_usage);
+               argv++; argc--;
        }
 
+       /* At this point, if argc == 1, then we are doing everything.
+        * Otherwise argv[1] .. argv[argc-1] have the explicit paths.
+        */
        if (entries < 0) {
                perror("read_cache");
                exit(1);
@@ -76,31 +157,56 @@ int main(int argc, char **argv)
        for (i = 0; i < entries; i++) {
                struct stat st;
                struct cache_entry *ce = active_cache[i];
-               int n, changed;
+               int changed;
                unsigned long size;
                char type[20];
-               void *new;
+               void *old;
 
+               if (1 < argc &&
+                   ! matches_pathspec(ce, argv+1, argc-1))
+                       continue;
+
+               if (ce_stage(ce)) {
+                       if (machine_readable)
+                               printf("U %s%c", ce->name, 0);
+                       else
+                               printf("%s: Unmerged\n",
+                                      ce->name);
+                       while (i < entries &&
+                              !strcmp(ce->name, active_cache[i]->name))
+                               i++;
+                       i--; /* compensate for loop control increments */
+                       continue;
+               }
+ 
                if (stat(ce->name, &st) < 0) {
-                       printf("%s: %s\n", ce->name, strerror(errno));
-                       if (errno == ENOENT && !silent)
-                               show_diff_empty(ce);
+                       if (errno == ENOENT && silent_on_nonexisting_files)
+                               continue;
+                       if (machine_readable)
+                               printf("X %s%c", ce->name, 0);
+                       else {
+                               printf("%s: %s\n", ce->name, strerror(errno));
+                               if (errno == ENOENT)
+                                       show_diff_empty(ce);
+                       }
                        continue;
                }
                changed = cache_match_stat(ce, &st);
                if (!changed)
                        continue;
-               printf("%.*s:  ", ce_namelen(ce), ce->name);
-               for (n = 0; n < 20; n++)
-                       printf("%02x", ce->sha1[n]);
-               printf("\n");
+               if (!machine_readable)
+                       printf("%s: %s\n", ce->name, sha1_to_hex(ce->sha1));
+               else {
+                       printf("%s %s%c", sha1_to_hex(ce->sha1), ce->name, 0);
+                       continue;
+               }
                fflush(stdout);
                if (silent)
                        continue;
 
-               new = read_sha1_file(ce->sha1, type, &size);
-               show_differences(ce->name, new, size);
-               free(new);
+               old = read_sha1_file(ce->sha1, type, &size);
+               show_differences(ce->name, old, size);
+               free(old);
        }
        return 0;
 }