Support 'diff=pgm' attribute
[git/git.git] / diff.c
diff --git a/diff.c b/diff.c
index f516664..9dfded7 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -52,6 +52,49 @@ static int parse_diff_color_slot(const char *var, int ofs)
        die("bad config variable '%s'", var);
 }
 
        die("bad config variable '%s'", var);
 }
 
+static struct ll_diff_driver {
+       const char *name;
+       struct ll_diff_driver *next;
+       char *cmd;
+} *user_diff, **user_diff_tail;
+
+/*
+ * Currently there is only "diff.<drivername>.command" variable;
+ * because there are "diff.color.<slot>" variables, we are parsing
+ * this in a bit convoluted way to allow low level diff driver
+ * called "color".
+ */
+static int parse_lldiff_command(const char *var, const char *ep, const char *value)
+{
+       const char *name;
+       int namelen;
+       struct ll_diff_driver *drv;
+
+       name = var + 5;
+       namelen = ep - name;
+       for (drv = user_diff; drv; drv = drv->next)
+               if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
+                       break;
+       if (!drv) {
+               char *namebuf;
+               drv = xcalloc(1, sizeof(struct ll_diff_driver));
+               namebuf = xmalloc(namelen + 1);
+               memcpy(namebuf, name, namelen);
+               namebuf[namelen] = 0;
+               drv->name = namebuf;
+               drv->next = NULL;
+               if (!user_diff_tail)
+                       user_diff_tail = &user_diff;
+               *user_diff_tail = drv;
+               user_diff_tail = &(drv->next);
+       }
+
+       if (!value)
+               return error("%s: lacks value", var);
+       drv->cmd = strdup(value);
+       return 0;
+}
+
 /*
  * These are to give UI layer defaults.
  * The core-level commands such as git-diff-files should
 /*
  * These are to give UI layer defaults.
  * The core-level commands such as git-diff-files should
@@ -78,11 +121,18 @@ int git_diff_ui_config(const char *var, const char *value)
                        diff_detect_rename_default = DIFF_DETECT_RENAME;
                return 0;
        }
                        diff_detect_rename_default = DIFF_DETECT_RENAME;
                return 0;
        }
+       if (!prefixcmp(var, "diff.")) {
+               const char *ep = strrchr(var, '.');
+
+               if (ep != var + 4 && !strcmp(ep, ".command"))
+                       return parse_lldiff_command(var, ep, value);
+       }
        if (!prefixcmp(var, "diff.color.") || !prefixcmp(var, "color.diff.")) {
                int slot = parse_diff_color_slot(var, 11);
                color_parse(value, var, diff_colors[slot]);
                return 0;
        }
        if (!prefixcmp(var, "diff.color.") || !prefixcmp(var, "color.diff.")) {
                int slot = parse_diff_color_slot(var, 11);
                color_parse(value, var, diff_colors[slot]);
                return 0;
        }
+
        return git_default_config(var, value);
 }
 
        return git_default_config(var, value);
 }
 
@@ -1074,11 +1124,6 @@ static int file_is_binary(struct diff_filespec *one)
                        return 0;
                else if (ATTR_FALSE(value))
                        return 1;
                        return 0;
                else if (ATTR_FALSE(value))
                        return 1;
-               else if (ATTR_UNSET(value))
-                       ;
-               else
-                       die("unknown value %s given to 'diff' attribute",
-                           value);
        }
 
        if (!one->data) {
        }
 
        if (!one->data) {
@@ -1752,6 +1797,30 @@ static void run_external_diff(const char *pgm,
        }
 }
 
        }
 }
 
+static const char *external_diff_attr(const char *name)
+{
+       struct git_attr_check attr_diff_check;
+
+       setup_diff_attr_check(&attr_diff_check);
+       if (!git_checkattr(name, 1, &attr_diff_check)) {
+               const char *value = attr_diff_check.value;
+               if (!ATTR_TRUE(value) &&
+                   !ATTR_FALSE(value) &&
+                   !ATTR_UNSET(value)) {
+                       struct ll_diff_driver *drv;
+
+                       if (!user_diff_tail) {
+                               user_diff_tail = &user_diff;
+                               git_config(git_diff_ui_config);
+                       }
+                       for (drv = user_diff; drv; drv = drv->next)
+                               if (!strcmp(drv->name, value))
+                                       return drv->cmd;
+               }
+       }
+       return NULL;
+}
+
 static void run_diff_cmd(const char *pgm,
                         const char *name,
                         const char *other,
 static void run_diff_cmd(const char *pgm,
                         const char *name,
                         const char *other,
@@ -1761,6 +1830,14 @@ static void run_diff_cmd(const char *pgm,
                         struct diff_options *o,
                         int complete_rewrite)
 {
                         struct diff_options *o,
                         int complete_rewrite)
 {
+       if (!o->allow_external)
+               pgm = NULL;
+       else {
+               const char *cmd = external_diff_attr(name);
+               if (cmd)
+                       pgm = cmd;
+       }
+
        if (pgm) {
                run_external_diff(pgm, name, other, one, two, xfrm_msg,
                                  complete_rewrite);
        if (pgm) {
                run_external_diff(pgm, name, other, one, two, xfrm_msg,
                                  complete_rewrite);