From 4c7fdb4d3d7b24e4bca69a710d347cfeb05ac78f Mon Sep 17 00:00:00 2001
From: Ben Straub <bs@github.com>
Date: Mon, 16 Sep 2013 16:27:10 -0700
Subject: [PATCH] Add blame example

---
 examples/.gitignore |   1 +
 examples/Makefile   |   2 +-
 examples/blame.c    | 131 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 133 insertions(+), 1 deletion(-)
 create mode 100644 examples/blame.c

diff --git a/examples/.gitignore b/examples/.gitignore
index e8e0820a5..2b693f1ef 100644
--- a/examples/.gitignore
+++ b/examples/.gitignore
@@ -2,4 +2,5 @@ general
 showindex
 diff
 rev-list
+blame
 *.dSYM
diff --git a/examples/Makefile b/examples/Makefile
index d53ed8241..79c57d7d7 100644
--- a/examples/Makefile
+++ b/examples/Makefile
@@ -3,7 +3,7 @@
 CC = gcc
 CFLAGS = -g -I../include -I../src -Wall -Wextra -Wmissing-prototypes -Wno-missing-field-initializers
 LFLAGS = -L../build -lgit2 -lz
-APPS = general showindex diff rev-list cat-file status log rev-parse init
+APPS = general blame showindex diff rev-list cat-file status log rev-parse
 
 all: $(APPS)
 
diff --git a/examples/blame.c b/examples/blame.c
new file mode 100644
index 000000000..1b08ec487
--- /dev/null
+++ b/examples/blame.c
@@ -0,0 +1,131 @@
+#include <stdio.h>
+#include <git2.h>
+#include <stdlib.h>
+#include <string.h>
+
+static void check(int error, const char *msg)
+{
+	if (error) {
+		fprintf(stderr, "%s (%d)\n", msg, error);
+		exit(error);
+	}
+}
+
+static void usage(const char *msg, const char *arg)
+{
+	if (msg && arg)
+		fprintf(stderr, "%s: %s\n", msg, arg);
+	else if (msg)
+		fprintf(stderr, "%s\n", msg);
+	fprintf(stderr, "usage: blame <path> [options] [<commit range>]\n");
+	fprintf(stderr, "\n");
+	fprintf(stderr, "   <commit range>      example: `HEAD~10..HEAD`, or `1234abcd`\n");
+	fprintf(stderr, "   -L <n,m>            process only line range n-m, counting from 1\n");
+	fprintf(stderr, "   -M                  fine line moves within and across files\n");
+	fprintf(stderr, "   -C                  find line copies within and across files\n");
+	fprintf(stderr, "\n");
+	exit(1);
+}
+
+int main(int argc, char *argv[])
+{
+	int i;
+	char *path = NULL, *a;
+	const char *rawdata, *commitspec=NULL;
+	git_repository *repo = NULL;
+	git_revspec revspec = {0};
+	git_blame_options opts = GIT_BLAME_OPTIONS_INIT;
+	git_blame *blame = NULL;
+	git_commit *commit;
+	git_tree *tree;
+	git_tree_entry *entry;
+	git_blob *blob;
+
+	if (argc < 2) usage(NULL, NULL);
+	path = argv[1];
+
+	for (i=2; i<argc; i++) {
+		a = argv[i];
+
+		if (!strcmp(a, "-M"))
+			opts.flags |= GIT_BLAME_TRACK_COPIES_SAME_COMMIT_MOVES;
+		else if (!strcmp(a, "-C"))
+			opts.flags |= GIT_BLAME_TRACK_COPIES_SAME_COMMIT_COPIES;
+		else if (!strncmp(a, "-L", 3)) {
+			i++; a = argv[i];
+			if (i >= argc) check(-1, "Not enough arguments to -L");
+			check(sscanf(a, "%d,%d", &opts.min_line, &opts.max_line)-2, "-L format error");
+		}
+		else {
+			/* commit range */
+			if (commitspec) check(-1, "Only one commit spec allowed");
+			commitspec = a;
+		}
+	}
+
+	/* Open the repo */
+	check(git_repository_open_ext(&repo, ".", 0, NULL), "Couldn't open repository");
+
+	/* Parse the end points */
+	if (commitspec) {
+		check(git_revparse(&revspec, repo, commitspec), "Couldn't parse commit spec");
+		if (revspec.flags & GIT_REVPARSE_SINGLE) {
+			git_oid_cpy(&opts.newest_commit, git_object_id(revspec.from));
+			git_object_free(revspec.from);
+		} else {
+			git_oid_cpy(&opts.oldest_commit, git_object_id(revspec.from));
+			git_oid_cpy(&opts.newest_commit, git_object_id(revspec.to));
+			git_object_free(revspec.from);
+			git_object_free(revspec.to);
+		}
+	}
+
+	/* Run the blame */
+	check(git_blame_file(&blame, repo, path, &opts), "Blame error");
+
+	/* Get the raw data for output */
+	if (git_oid_iszero(&opts.newest_commit)) {
+		git_object *obj;
+		check(git_revparse_single(&obj, repo, "HEAD"), "Can't find HEAD");
+		git_oid_cpy(&opts.newest_commit, git_object_id(obj));
+		git_object_free(obj);
+	}
+	check(git_commit_lookup(&commit, repo, &opts.newest_commit), "Commit lookup error");
+	check(git_commit_tree(&tree, commit), "Commit tree lookup error");
+	check(git_tree_entry_bypath(&entry, tree, path), "Tree entry lookup error");
+	check(git_blob_lookup(&blob, repo, git_tree_entry_id(entry)), "Blob lookup error");
+	rawdata = git_blob_rawcontent(blob);
+
+	/* Produce the output */
+	i = 1;
+	while (rawdata[0]) {
+		const char *eol = strchr(rawdata, '\n');
+		char oid[10] = {0};
+		const git_blame_hunk *hunk = git_blame_get_hunk_byline(blame, i);
+		git_commit *hunkcommit;
+		const git_signature *sig;
+
+		git_oid_tostr(oid, 10, &hunk->final_commit_id);
+		check(git_commit_lookup(&hunkcommit, repo, &hunk->final_commit_id), "Commit lookup error");
+		sig = git_commit_author(hunkcommit);
+
+		printf("%s ( %-30s %3d) %.*s\n",
+				oid,
+				sig->name,
+				i,
+				(int)(eol-rawdata),
+				rawdata);
+
+		git_commit_free(hunkcommit);
+		rawdata = eol+1;
+		i++;
+	}
+
+	/* Cleanup */
+	git_blob_free(blob);
+	git_tree_entry_free(entry);
+	git_tree_free(tree);
+	git_commit_free(commit);
+	git_blame_free(blame);
+	git_repository_free(repo);
+}