git-blame: --show-number (and -n)

The new option makes the command's native output format show the
original line number in the blamed revision.

Note: the current implementation of find_orig_linenum involves
linear search through the line_map array every time.  It should
probably build a reverse map upfront and do a simple look-up to
speed things up, but I'll leave it to more clever and beautiful
people ;-).

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/blame.c b/blame.c
index d830b29..bf4a1a1 100644 (file)
--- a/blame.c
+++ b/blame.c
@@ -731,6 +731,25 @@ static int read_ancestry(const char *graft_file,
        return 0;
 }
 
+static int lineno_width(int lines)
+{
+       int i, width;
+
+       for (width = 1, i = 10; i <= lines + 1; width++)
+               i *= 10;
+       return width;
+}
+
+static int find_orig_linenum(struct util_info *u, int lineno)
+{
+       int i;
+
+       for (i = 0; i < u->num_lines; i++)
+               if (lineno == u->line_map[i])
+                       return i + 1;
+       return 0;
+}
+
 int main(int argc, const char **argv)
 {
        int i;
@@ -750,9 +769,10 @@ int main(int argc, const char **argv)
 
        struct commit_info ci;
        const char *buf;
-       int max_digits;
-       int longest_file, longest_author;
+       int max_digits, max_orig_digits;
+       int longest_file, longest_author, longest_file_lines;
        int show_name = 0;
+       int show_number = 0;
 
        const char *prefix = setup_git_directory();
        git_config(git_default_config);
@@ -791,6 +811,11 @@ int main(int argc, const char **argv)
                                show_name = 1;
                                continue;
                        }
+                       if (!strcmp(argv[i], "-n") ||
+                           !strcmp(argv[i], "--show-number")) {
+                               show_number = 1;
+                               continue;
+                       }
                        if (!strcmp(argv[i], "--")) {
                                options = 0;
                                continue;
@@ -853,11 +878,11 @@ int main(int argc, const char **argv)
        process_commits(&rev, filename, &initial);
 
        buf = blame_contents;
-       for (max_digits = 1, i = 10; i <= num_blame_lines + 1; max_digits++)
-               i *= 10;
+       max_digits = lineno_width(num_blame_lines);
 
        longest_file = 0;
        longest_author = 0;
+       longest_file_lines = 0;
        for (i = 0; i < num_blame_lines; i++) {
                struct commit *c = blame_lines[i];
                struct util_info *u;
@@ -869,17 +894,23 @@ int main(int argc, const char **argv)
                        show_name = 1;
                if (longest_file < strlen(u->pathname))
                        longest_file = strlen(u->pathname);
+               if (longest_file_lines < u->num_lines)
+                       longest_file_lines = u->num_lines;
                get_commit_info(c, &ci);
                if (longest_author < strlen(ci.author))
                        longest_author = strlen(ci.author);
        }
 
+       max_orig_digits = lineno_width(longest_file_lines);
+
        for (i = 0; i < num_blame_lines; i++) {
                struct commit *c = blame_lines[i];
                struct util_info *u;
+               int lineno;
                if (!c)
                        c = initial;
                u = c->util;
+               lineno = find_orig_linenum(u, i);
 
                get_commit_info(c, &ci);
                fwrite(sha1_to_hex(c->object.sha1), sha1_len, 1, stdout);
@@ -893,6 +924,9 @@ int main(int argc, const char **argv)
                        if (show_name)
                                printf(" %-*.*s", longest_file, longest_file,
                                       u->pathname);
+                       if (show_number)
+                               printf(" %*d", max_orig_digits,
+                                      lineno);
                        printf(" (%-*.*s %10s %*d) ",
                               longest_author, longest_author, ci.author,
                               format_time(ci.author_time, ci.author_tz,