X-Git-Url: https://git.verplant.org/?a=blobdiff_plain;f=rev-parse.c;h=40707ac6ca7258878b47ed72074b3cf7364d3a56;hb=180926636e47ecfe28d03cec493af75899994f0f;hp=fd5f2ddca36ea45cd9feaf706a53aa66956db233;hpb=921d865ea24ffea6452f9b24302e651a347d7905;p=git.git

diff --git a/rev-parse.c b/rev-parse.c
index fd5f2ddc..40707ac6 100644
--- a/rev-parse.c
+++ b/rev-parse.c
@@ -4,6 +4,9 @@
  * Copyright (C) Linus Torvalds, 2005
  */
 #include "cache.h"
+#include "commit.h"
+
+static int get_extended_sha1(char *name, unsigned char *sha1);
 
 /*
  * Some arguments are relevant "revision" arguments,
@@ -32,6 +35,56 @@ static int is_rev_argument(const char *arg)
 	}
 }
 
+static int get_parent(char *name, unsigned char *result, int idx)
+{
+	unsigned char sha1[20];
+	int ret = get_extended_sha1(name, sha1);
+	struct commit *commit;
+	struct commit_list *p;
+
+	if (ret)
+		return ret;
+	commit = lookup_commit_reference(sha1);
+	if (!commit)
+		return -1;
+	if (parse_commit(commit))
+		return -1;
+	p = commit->parents;
+	while (p) {
+		if (!--idx) {
+			memcpy(result, p->item->object.sha1, 20);
+			return 0;
+		}
+		p = p->next;
+	}
+	return -1;
+}
+
+/*
+ * This is like "get_sha1()", except it allows "sha1 expressions",
+ * notably "xyz^" for "parent of xyz"
+ */
+static int get_extended_sha1(char *name, unsigned char *sha1)
+{
+	int parent;
+	int len = strlen(name);
+
+	parent = 1;
+	if (len > 2 && name[len-1] >= '1' && name[len-1] <= '9') {
+		parent = name[len-1] - '0';
+		len--;
+	}
+	if (len > 1 && name[len-1] == '^') {
+		int ret;
+		name[len-1] = 0;
+		ret = get_parent(name, sha1, parent);
+		name[len-1] = '^';
+		if (!ret)
+			return 0;
+	}
+	return get_sha1(name, sha1);
+}
+
 int main(int argc, char **argv)
 {
 	int i, as_is = 0, revs_only = 0, no_revs = 0;
@@ -78,29 +131,15 @@ int main(int argc, char **argv)
 			printf("%s\n", arg);
 			continue;
 		}
-		if (!get_sha1(arg, sha1)) {
-			if (no_revs)
-				continue;
-			def = NULL;
-			printf("%s\n", sha1_to_hex(sha1));
-			continue;
-		}
-		if (*arg == '^' && !get_sha1(arg+1, sha1)) {
-			if (no_revs)
-				continue;
-			def = NULL;
-			printf("^%s\n", sha1_to_hex(sha1));
-			continue;
-		}
 		dotdot = strstr(arg, "..");
 		if (dotdot) {
 			unsigned char end[20];
 			char *n = dotdot+2;
 			*dotdot = 0;
-			if (!get_sha1(arg, sha1)) {
+			if (!get_extended_sha1(arg, sha1)) {
 				if (!*n)
 					n = "HEAD";
-				if (!get_sha1(n, end)) {
+				if (!get_extended_sha1(n, end)) {
 					if (no_revs)
 						continue;
 					def = NULL;
@@ -111,9 +150,26 @@ int main(int argc, char **argv)
 			}
 			*dotdot = '.';
 		}
+		if (!get_extended_sha1(arg, sha1)) {
+			if (no_revs)
+				continue;
+			def = NULL;
+			printf("%s\n", sha1_to_hex(sha1));
+			continue;
+		}
+		if (*arg == '^' && !get_extended_sha1(arg+1, sha1)) {
+			if (no_revs)
+				continue;
+			def = NULL;
+			printf("^%s\n", sha1_to_hex(sha1));
+			continue;
+		}
+		if (def) {
+			printf("%s\n", def);
+			def = NULL;
+		}
 		if (revs_only)
 			continue;
-		def = NULL;
 		printf("%s\n", arg);
 	}
 	if (def)