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-rw-r--r--builtin/patch-id.c201
1 files changed, 201 insertions, 0 deletions
diff --git a/builtin/patch-id.c b/builtin/patch-id.c
new file mode 100644
index 0000000000..ba34dac4d2
--- /dev/null
+++ b/builtin/patch-id.c
@@ -0,0 +1,201 @@
+#include "builtin.h"
+
+static void flush_current_id(int patchlen, struct object_id *id, struct object_id *result)
+{
+ char name[50];
+
+ if (!patchlen)
+ return;
+
+ memcpy(name, oid_to_hex(id), GIT_SHA1_HEXSZ + 1);
+ printf("%s %s\n", oid_to_hex(result), name);
+}
+
+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 int scan_hunk_header(const char *p, int *p_before, int *p_after)
+{
+ static const char digits[] = "0123456789";
+ const char *q, *r;
+ int n;
+
+ q = p + 4;
+ n = strspn(q, digits);
+ if (q[n] == ',') {
+ q += n + 1;
+ n = strspn(q, digits);
+ }
+ if (n == 0 || q[n] != ' ' || q[n+1] != '+')
+ return 0;
+
+ r = q + n + 2;
+ n = strspn(r, digits);
+ if (r[n] == ',') {
+ r += n + 1;
+ n = strspn(r, digits);
+ }
+ if (n == 0)
+ return 0;
+
+ *p_before = atoi(q);
+ *p_after = atoi(r);
+ return 1;
+}
+
+static void flush_one_hunk(struct object_id *result, git_SHA_CTX *ctx)
+{
+ unsigned char hash[GIT_SHA1_RAWSZ];
+ unsigned short carry = 0;
+ int i;
+
+ git_SHA1_Final(hash, ctx);
+ git_SHA1_Init(ctx);
+ /* 20-byte sum, with carry */
+ for (i = 0; i < GIT_SHA1_RAWSZ; ++i) {
+ carry += result->hash[i] + hash[i];
+ result->hash[i] = carry;
+ carry >>= 8;
+ }
+}
+
+static int get_one_patchid(struct object_id *next_oid, struct object_id *result,
+ struct strbuf *line_buf, int stable)
+{
+ int patchlen = 0, found_next = 0;
+ int before = -1, after = -1;
+ git_SHA_CTX ctx;
+
+ git_SHA1_Init(&ctx);
+ oidclr(result);
+
+ while (strbuf_getwholeline(line_buf, stdin, '\n') != EOF) {
+ char *line = line_buf->buf;
+ char *p = line;
+ int len;
+
+ if (!memcmp(line, "diff-tree ", 10))
+ p += 10;
+ else if (!memcmp(line, "commit ", 7))
+ p += 7;
+ else if (!memcmp(line, "From ", 5))
+ p += 5;
+ else if (!memcmp(line, "\\ ", 2) && 12 < strlen(line))
+ continue;
+
+ if (!get_oid_hex(p, next_oid)) {
+ found_next = 1;
+ break;
+ }
+
+ /* Ignore commit comments */
+ if (!patchlen && memcmp(line, "diff ", 5))
+ continue;
+
+ /* Parsing diff header? */
+ if (before == -1) {
+ if (!memcmp(line, "index ", 6))
+ continue;
+ else if (!memcmp(line, "--- ", 4))
+ before = after = 1;
+ else if (!isalpha(line[0]))
+ break;
+ }
+
+ /* Looking for a valid hunk header? */
+ if (before == 0 && after == 0) {
+ if (!memcmp(line, "@@ -", 4)) {
+ /* Parse next hunk, but ignore line numbers. */
+ scan_hunk_header(line, &before, &after);
+ continue;
+ }
+
+ /* Split at the end of the patch. */
+ if (memcmp(line, "diff ", 5))
+ break;
+
+ /* Else we're parsing another header. */
+ if (stable)
+ flush_one_hunk(result, &ctx);
+ before = after = -1;
+ }
+
+ /* If we get here, we're inside a hunk. */
+ if (line[0] == '-' || line[0] == ' ')
+ before--;
+ if (line[0] == '+' || line[0] == ' ')
+ after--;
+
+ /* Compute the sha without whitespace */
+ len = remove_space(line);
+ patchlen += len;
+ git_SHA1_Update(&ctx, line, len);
+ }
+
+ if (!found_next)
+ oidclr(next_oid);
+
+ flush_one_hunk(result, &ctx);
+
+ return patchlen;
+}
+
+static void generate_id_list(int stable)
+{
+ struct object_id oid, n, result;
+ int patchlen;
+ struct strbuf line_buf = STRBUF_INIT;
+
+ oidclr(&oid);
+ while (!feof(stdin)) {
+ patchlen = get_one_patchid(&n, &result, &line_buf, stable);
+ flush_current_id(patchlen, &oid, &result);
+ oidcpy(&oid, &n);
+ }
+ strbuf_release(&line_buf);
+}
+
+static const char patch_id_usage[] = "git patch-id [--stable | --unstable] < patch";
+
+static int git_patch_id_config(const char *var, const char *value, void *cb)
+{
+ int *stable = cb;
+
+ if (!strcmp(var, "patchid.stable")) {
+ *stable = git_config_bool(var, value);
+ return 0;
+ }
+
+ return git_default_config(var, value, cb);
+}
+
+int cmd_patch_id(int argc, const char **argv, const char *prefix)
+{
+ int stable = -1;
+
+ git_config(git_patch_id_config, &stable);
+
+ /* If nothing is set, default to unstable. */
+ if (stable < 0)
+ stable = 0;
+
+ if (argc == 2 && !strcmp(argv[1], "--stable"))
+ stable = 1;
+ else if (argc == 2 && !strcmp(argv[1], "--unstable"))
+ stable = 0;
+ else if (argc != 1)
+ usage(patch_id_usage);
+
+ generate_id_list(stable);
+ return 0;
+}