Add "git-patch-id" program to generate patch ID's.

[git.git] / patch-id.c

diff --git a/patch-id.c b/patch-id.c
new file mode 100644 (file)
index 0000000..0bd640c
--- /dev/null
+++ b/patch-id.c
@@ -0,0 +1,79 @@
+#include <ctype.h>
+#include "cache.h"
+
+static void flush_current_id(int patchlen, unsigned char *id, SHA_CTX *c)
+{
+       unsigned char result[20];
+       char name[50];
+
+       if (!patchlen)
+               return;
+
+       SHA1_Final(result, c);
+       memcpy(name, sha1_to_hex(id), 41);
+       printf("%s %s\n", sha1_to_hex(result), name);
+       SHA1_Init(c);
+}
+
+static int remove_space(char *line)
+{
+       char *src = line;
+       char *dst = line;
+       unsigned char c;
+
+       while ((c = *src++) != '\0') {
+               if (!isspace(c))
+                       *dst++ = c;
+       }
+       return dst - line;
+}
+
+static void generate_id_list(void)
+{
+       static unsigned char sha1[20];
+       static char line[1000];
+       SHA_CTX ctx;
+       int patchlen = 0;
+
+       SHA1_Init(&ctx);
+       while (fgets(line, sizeof(line), stdin) != NULL) {
+               unsigned char n[20];
+               char *p = line;
+               int len;
+
+               if (!memcmp(line, "diff-tree ", 10))
+                       p += 10;
+
+               if (!get_sha1_hex(p, n)) {
+                       flush_current_id(patchlen, sha1, &ctx);
+                       memcpy(sha1, n, 20);
+                       patchlen = 0;
+                       continue;
+               }
+
+               /* Ignore commit comments */
+               if (!patchlen && memcmp(line, "diff ", 5))
+                       continue;
+
+               /* Ignore line numbers when computing the SHA1 of the patch */
+               if (!memcmp(line, "@@ -", 4))
+                       continue;
+
+               /* Compute the sha without whitespace */
+               len = remove_space(line);
+               patchlen += len;
+               SHA1_Update(&ctx, line, len);
+       }
+       flush_current_id(patchlen, sha1, &ctx);
+}
+
+static const char patch_id_usage[] = "usage: git-patch-id < patch";
+
+int main(int argc, char **argv)
+{
+       if (argc != 1)
+               usage(patch_id_usage);
+
+       generate_id_list();
+       return 0;
+}