[PATCH] simplify Makefile
[gitweb.git] / show-diff.c
index 15dcd0525ed944c6f82f93a1744c15e2f3325e61..2ff0bd4ea636db2ad54e9ff34e1d70ac7a9a98f0 100644 (file)
  */
 #include "cache.h"
 
-static void show_differences(char *name,
-       void *old_contents, unsigned long long old_size)
+static char *diff_cmd = "diff -L 'a/%s' -L 'b/%s' ";
+static char *diff_opts = "-p -u";
+static char *diff_arg_forward  = " - '%s'";
+static char *diff_arg_reverse  = " '%s' -";
+
+static void prepare_diff_cmd(void)
+{
+       /*
+        * Default values above are meant to match the
+        * Linux kernel development style.  Examples of
+        * alternative styles you can specify via environment
+        * variables are:
+        *
+        * GIT_DIFF_CMD="diff -L '%s' -L '%s'"
+        * GIT_DIFF_OPTS="-c";
+        */
+       diff_cmd = getenv("GIT_DIFF_CMD") ? : diff_cmd;
+       diff_opts = getenv("GIT_DIFF_OPTS") ? : diff_opts;
+}
+
+/* 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'
+ */
+static char *sq_expand(char *src)
+{
+       static char *buf = NULL;
+       int cnt, c;
+       char *cp;
+
+       /* count bytes needed to store the quoted string. */ 
+       for (cnt = 1, cp = src; *cp; cnt++, cp++)
+               if (*cp == '\'')
+                       cnt += 3;
+
+       if (! (buf = malloc(cnt)))
+           return buf;
+       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, char *label, void *old_contents,
+                            unsigned long long old_size, int reverse)
 {
-       static char cmd[1000];
        FILE *f;
+       char *name_sq = sq_expand(name);
+       char *label_sq = (name != label) ? sq_expand(label) : name_sq;
+       char *diff_arg = reverse ? diff_arg_reverse : diff_arg_forward;
+       int cmd_size = strlen(name_sq) + strlen(label_sq) * 2 +
+               strlen(diff_cmd) + strlen(diff_opts) + strlen(diff_arg);
+       char *cmd = malloc(cmd_size);
+       int next_at;
 
-       snprintf(cmd, sizeof(cmd), "diff -L %s -u -N  - %s", name, name);
+       fflush(stdout);
+       next_at = snprintf(cmd, cmd_size, diff_cmd, label_sq, label_sq);
+       next_at += snprintf(cmd+next_at, cmd_size-next_at, "%s", diff_opts);
+       next_at += snprintf(cmd+next_at, cmd_size-next_at, diff_arg, name_sq);
        f = popen(cmd, "w");
        if (old_size)
                fwrite(old_contents, old_size, 1, f);
        pclose(f);
+       if (label_sq != name_sq)
+               free(label_sq);
+       free(name_sq);
+       free(cmd);
 }
 
-static void show_diff_empty(struct cache_entry *ce)
+static void show_diff_empty(struct cache_entry *ce, int reverse)
 {
        char *old;
        unsigned long int size;
-       int lines=0;
-       unsigned char type[20], *p, *end;
+       unsigned char type[20];
 
        old = read_sha1_file(ce->sha1, type, &size);
-       if (size > 0) {
-               int startline = 1;
-               int c = 0;
-
-               printf("--- %s\n", ce->name);
-               printf("+++ /dev/null\n");
-               p = old;
-               end = old + size;
-               while (p < end)
-                       if (*p++ == '\n')
-                               lines ++;
-               printf("@@ -1,%d +0,0 @@\n", lines);
-               p = old;
-               while (p < end) {
-                       c = *p++;
-                       if (startline) {
-                               putchar('-');
-                               startline = 0;
-                       }
-                       putchar(c);
-                       if (c == '\n')
-                               startline = 1;
-               }
-               if (c!='\n')
-                       printf("\n");
-               fflush(stdout);
+       if (! old) {
+               error("unable to read blob object for %s (%s)", ce->name,
+                     sha1_to_hex(ce->sha1));
+               return;
        }
+       show_differences("/dev/null", ce->name, old, size, reverse);
+}
+
+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 reverse = 0;
        int entries = read_cache();
        int i;
 
-       for (i = 1; i < argc; i++) {
-               if (!strcmp(argv[i], "-s")) {
+       while (1 < argc && argv[1][0] == '-') {
+               if  (!strcmp(argv[1], "-R"))
+                       reverse = 1;
+               else if (!strcmp(argv[1], "-s"))
                        silent_on_nonexisting_files = silent = 1;
-                       continue;
-               }
-               if (!strcmp(argv[i], "-q")) {
+               else if (!strcmp(argv[1], "-q"))
                        silent_on_nonexisting_files = 1;
-                       continue;
-               }
-               usage("show-diff [-s] [-q]");
+               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);
        }
+       prepare_diff_cmd();
        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) {
                        if (errno == ENOENT && silent_on_nonexisting_files)
                                continue;
-                       printf("%s: %s\n", ce->name, strerror(errno));
-                       if (errno == ENOENT)
-                               show_diff_empty(ce);
+                       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, reverse);
+                       }
                        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");
-               fflush(stdout);
+               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;
+               }
                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);
+               if (! old)
+                       error("unable to read blob object for %s (%s)",
+                             ce->name, sha1_to_hex(ce->sha1));
+               else
+                       show_differences(ce->name, ce->name, old, size,
+                                        reverse);
+               free(old);
        }
        return 0;
 }