Merge branch 'dont-spawn-gzip-in-archive'

This topic branch avoids spawning `gzip` when asking `git archive` to
create `.tar.gz` files.

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

archive-tar.c

@@ -17,6 +17,8 @@ static unsigned long offset;
 
 static int tar_umask = 002;
 
+static gzFile gzip;
+
 static int write_tar_filter_archive(const struct archiver *ar,
 				    struct archiver_args *args);
 
@@ -38,11 +40,21 @@ static int write_tar_filter_archive(const struct archiver *ar,
 #define USTAR_MAX_MTIME 077777777777ULL
 #endif
 
+/* writes out the whole block, or dies if fails */
+static void write_block_or_die(const char *block) {
+	if (gzip) {
+		if (gzwrite(gzip, block, (unsigned) BLOCKSIZE) != BLOCKSIZE)
+			die(_("gzwrite failed"));
+	} else {
+		write_or_die(1, block, BLOCKSIZE);
+	}
+}
+
 /* writes out the whole block, but only if it is full */
 static void write_if_needed(void)
 {
 	if (offset == BLOCKSIZE) {
-		write_or_die(1, block, BLOCKSIZE);
+		write_block_or_die(block);
 		offset = 0;
 	}
 }
@@ -66,7 +78,7 @@ static void do_write_blocked(const void *data, unsigned long size)
 		write_if_needed();
 	}
 	while (size >= BLOCKSIZE) {
-		write_or_die(1, buf, BLOCKSIZE);
+		write_block_or_die(buf);
 		size -= BLOCKSIZE;
 		buf += BLOCKSIZE;
 	}
@@ -101,10 +113,10 @@ static void write_trailer(void)
 {
 	int tail = BLOCKSIZE - offset;
 	memset(block + offset, 0, tail);
-	write_or_die(1, block, BLOCKSIZE);
+	write_block_or_die(block);
 	if (tail < 2 * RECORDSIZE) {
 		memset(block, 0, offset);
-		write_or_die(1, block, BLOCKSIZE);
+		write_block_or_die(block);
 	}
 }
 
@@ -455,18 +467,34 @@ static int write_tar_filter_archive(const struct archiver *ar,
 	filter.use_shell = 1;
 	filter.in = -1;
 
-	if (start_command(&filter) < 0)
-		die_errno(_("unable to start '%s' filter"), argv[0]);
-	close(1);
-	if (dup2(filter.in, 1) < 0)
-		die_errno(_("unable to redirect descriptor"));
-	close(filter.in);
+	if (!strcmp("gzip -cn", ar->data)) {
+		char outmode[4] = "wb\0";
+
+		if (args->compression_level >= 0 && args->compression_level <= 9)
+			outmode[2] = '0' + args->compression_level;
+
+		gzip = gzdopen(fileno(stdout), outmode);
+		if (!gzip)
+			die(_("Could not gzdopen stdout"));
+	} else {
+		if (start_command(&filter) < 0)
+			die_errno(_("unable to start '%s' filter"), argv[0]);
+		close(1);
+		if (dup2(filter.in, 1) < 0)
+			die_errno(_("unable to redirect descriptor"));
+		close(filter.in);
+	}
 
 	r = write_tar_archive(ar, args);
 
-	close(1);
-	if (finish_command(&filter) != 0)
-		die(_("'%s' filter reported error"), argv[0]);
+	if (gzip) {
+		if (gzclose(gzip) != Z_OK)
+			die(_("gzclose failed"));
+	} else {
+		close(1);
+		if (finish_command(&filter) != 0)
+			die(_("'%s' filter reported error"), argv[0]);
+	}
 
 	strbuf_release(&cmd);
 	return r;