Enable output buffering in merge-recursive.

Buffering all message output until a merge invocation is complete is
necessary to prevent intereferring with a progress meter that would
indicate the number of files completely merged, and how many remain.
This change does not introduce a progress meter, but merely lays
the groundwork to buffer the output.

To aid debugging output buffering is only enabled if verbosity
is lower than 5.  When using verbosity levels above 5 the user is
probably debugging the merge program itself and does not want to
see the output delayed, especially if they are stepping through
portions of the code in a debugger.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/merge-recursive.c b/merge-recursive.c
index ef9932a68ccb11416e0412f02c5dade02505b104..9237a57f8e11e323d6f4b267e09583b3a6c9103b 100644 (file)
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -67,11 +67,19 @@ struct stage_data
        unsigned processed:1;
 };
 
+struct output_buffer
+{
+       struct output_buffer *next;
+       char *str;
+};
+
 static struct path_list current_file_set = {NULL, 0, 0, 1};
 static struct path_list current_directory_set = {NULL, 0, 0, 1};
 
 static int call_depth = 0;
 static int verbosity = 2;
+static int buffer_output = 1;
+static struct output_buffer *output_list, *output_end;
 
 static int show (int v)
 {
@@ -82,7 +90,16 @@ static void output(int v, const char *fmt, ...)
 {
        va_list args;
        va_start(args, fmt);
-       if (show(v)) {
+       if (buffer_output && show(v)) {
+               struct output_buffer *b = xmalloc(sizeof(*b));
+               nfvasprintf(&b->str, fmt, args);
+               b->next = NULL;
+               if (output_end)
+                       output_end->next = b;
+               else
+                       output_list = b;
+               output_end = b;
+       } else if (show(v)) {
                int i;
                for (i = call_depth; i--;)
                        fputs("  ", stdout);
@@ -92,9 +109,27 @@ static void output(int v, const char *fmt, ...)
        va_end(args);
 }
 
+static void flush_output()
+{
+       struct output_buffer *b, *n;
+       for (b = output_list; b; b = n) {
+               int i;
+               for (i = call_depth; i--;)
+                       fputs("  ", stdout);
+               fputs(b->str, stdout);
+               fputc('\n', stdout);
+               n = b->next;
+               free(b->str);
+               free(b);
+       }
+       output_list = NULL;
+       output_end = NULL;
+}
+
 static void output_commit_title(struct commit *commit)
 {
        int i;
+       flush_output();
        for (i = call_depth; i--;)
                fputs("  ", stdout);
        if (commit->util)
@@ -1175,6 +1210,7 @@ static int merge(struct commit *h1,
                commit_list_insert(h1, &(*result)->parents);
                commit_list_insert(h2, &(*result)->parents->next);
        }
+       flush_output();
        return clean;
 }
 
@@ -1252,6 +1288,8 @@ int main(int argc, char *argv[])
 
        branch1 = better_branch_name(branch1);
        branch2 = better_branch_name(branch2);
+       if (verbosity >= 5)
+               buffer_output = 0;
        if (show(3))
                printf("Merging %s with %s\n", branch1, branch2);