Thread (68 messages) 68 messages, 7 authors, 2022-02-22

Re: [PATCH 2/2] catfile.c: add --batch-command mode

From: Ævar Arnfjörð Bjarmason <hidden>
Date: 2022-02-04 12:22:47

On Thu, Feb 03 2022, John Cai via GitGitGadget wrote:
From: John Cai <redacted>
[Trying not to pile on and mentioning some things others haven't, but
maybe there'll be duplications]
quoted hunk ↗ jump to hunk
 	requested batch operation on all objects in the repository and
diff --git a/builtin/cat-file.c b/builtin/cat-file.c
index 858bca208ff..29d5cd6857b 100644
--- a/builtin/cat-file.c
+++ b/builtin/cat-file.c
@@ -26,6 +26,7 @@ struct batch_options {
 	int unordered;
 	int mode; /* may be 'w' or 'c' for --filters or --textconv */
 	const char *format;
+	int command;
 };
Not sure why it's not added to "int mode", but in any case
post-ab/cat-file that might be clearer...
+	/* Read each line dispatch its command */
+	while (!strbuf_getline(&input, stdin)) {
I think comments that are obvious from the code are probably best
dropped. We're just doing a fairly obvious consume stdin pattern here.
+		int i;
+		const struct parse_cmd *cmd = NULL;
+		const char *p, *cmd_end;
+
+		if (state == BATCH_STATE_COMMAND) {
+			if (*input.buf == '\n')
+				die("empty command in input");
+			else if (isspace(*input.buf))
+				die("whitespace before command: %s", input.buf);
These should use _() to mark strings for translation, and let's quote %s
like '%s'
+		}
+
+		for (i = 0; i < ARRAY_SIZE(commands); i++) {
+			const char *prefix = commands[i].prefix;
+			char c;
nit: add a \n between variable decls and code.
+			if (!skip_prefix(input.buf, prefix, &cmd_end))
+				continue;
+			/*
+			 * If the command has arguments, verify that it's
+			 * followed by a space. Otherwise, it shall be followed
+			 * by a line terminator.
+			 */
I'd say ditto on the "the code says that" comments...
+			c = commands[i].takes_args ? ' ' : '\n';
+			if (*cmd_end && *cmd_end != c)
+				die("arguments invalid for command: %s", commands[i].prefix);
+
+			cmd = &commands[i];
+			if (cmd->takes_args)
+				p = cmd_end + 1;
+			break;
+		}
+
+		if (input.buf[input.len - 1] == '\n')
+			input.buf[--input.len] = '\0';
Don't we mean strbuf_trim_trailing_newline() here, or do we not want
Windows newlines to be accepted?

But more generally doesn't one of the strbuf_getline_*() functions do
the right thing here already?
+
+		if (state == BATCH_STATE_INPUT && !cmd){
+			string_list_append(&revs, input.buf);
Nit: You can save yourself some malloc() churn here with:

    string_list_append_nodup(..., strbuf_detach(&input, NULL));

I.e. we're looping over the input, here we're done, so we might as well
steal the already alloc'd string....
+			continue;
+		}
+
+		if (!cmd)
+			die("unknown command: %s", input.buf);
+
+		state = cmd->next_state;
+		cmd->fn(opt, p, output, data, revs);
+	}
+	strbuf_release(&input);
+	string_list_clear(&revs, 0);
...and these will do the right thing, as strbuf will notice the string
is stolen (it'll be the slopbuf again), and due to the combination of
*_DUP and *_nodup() we'll properly free it here too.
quoted hunk ↗ jump to hunk
+}
+
 static int batch_objects(struct batch_options *opt)
 {
 	struct strbuf input = STRBUF_INIT;
@@ -519,6 +665,7 @@ static int batch_objects(struct batch_options *opt)
 	struct expand_data data;
 	int save_warning;
 	int retval = 0;
+	const int command = opt->command;
 
 	if (!opt->format)
 		opt->format = "%(objectname) %(objecttype) %(objectsize)";
@@ -594,22 +741,25 @@ static int batch_objects(struct batch_options *opt)
 	save_warning = warn_on_object_refname_ambiguity;
 	warn_on_object_refname_ambiguity = 0;
 
-	while (strbuf_getline(&input, stdin) != EOF) {
-		if (data.split_on_whitespace) {
-			/*
-			 * Split at first whitespace, tying off the beginning
-			 * of the string and saving the remainder (or NULL) in
-			 * data.rest.
-			 */
-			char *p = strpbrk(input.buf, " \t");
-			if (p) {
-				while (*p && strchr(" \t", *p))
-					*p++ = '\0';
+	if (command)
+		batch_objects_command(opt, &output, &data);
+	else {
Style: {} braces for all arms if one requires it.
+		while (strbuf_getline(&input, stdin) != EOF) {
+			if (data.split_on_whitespace) {
diff nit: maybe we can find some way to not require re-indenting the existing code. E.g.:
	
	if (command) {
		batch_objects_command(...);
	        goto cleanup;
	}

...
+				/*
+				 * Split at first whitespace, tying off the beginning
+				 * of the string and saving the remainder (or NULL) in
+				 * data.rest.
+				 */
+				char *p = strpbrk(input.buf, " \t");
+				if (p) {
+					while (*p && strchr(" \t", *p))
+						*p++ = '\0';
+				}
+				data.rest = p;
 			}
-			data.rest = p;
+			batch_one_object(input.buf, &output, opt, &data);
 		}
-
-		batch_one_object(input.buf, &output, opt, &data);
 	}
 
...and then just add a "cleanup:" label here.
quoted hunk ↗ jump to hunk
 	strbuf_release(&input);
@@ -646,6 +796,7 @@ static int batch_option_callback(const struct option *opt,
 
 	bo->enabled = 1;
 	bo->print_contents = !strcmp(opt->long_name, "batch");
+	bo->command = !strcmp(opt->long_name, "batch-command");
 	bo->format = arg;
 
 	return 0;
@@ -682,6 +833,11 @@ int cmd_cat_file(int argc, const char **argv, const char *prefix)
 			N_("show info about objects fed from the standard input"),
 			PARSE_OPT_OPTARG | PARSE_OPT_NONEG,
 			batch_option_callback),
+		OPT_CALLBACK_F(0, "batch-command", &batch, N_(""),
You're either missing a string here in "", or we don't need N_() to mark
it for translation.
quoted hunk ↗ jump to hunk
+			 N_("enters batch mode that accepts commands"),
+			 PARSE_OPT_OPTARG | PARSE_OPT_NONEG,
+			 batch_option_callback),
+
 		OPT_BOOL(0, "follow-symlinks", &batch.follow_symlinks,
 			 N_("follow in-tree symlinks (used with --batch or --batch-check)")),
 		OPT_BOOL(0, "batch-all-objects", &batch.all_objects,
diff --git a/t/t1006-cat-file.sh b/t/t1006-cat-file.sh
index 39382fa1958..7360d049113 100755
--- a/t/t1006-cat-file.sh
+++ b/t/t1006-cat-file.sh
@@ -85,6 +85,34 @@ $content"
 	test_cmp expect actual
     '
 
+    test -z "$content" ||
+    test_expect_success "--batch-command output of $type content is correct" '
+	maybe_remove_timestamp "$batch_output" $no_ts >expect &&
+	maybe_remove_timestamp "$(echo contents $sha1 | git cat-file --batch-command)" $no_ts >actual &&
+	test_cmp expect actual
+    '
+
+    test -z "$content" ||
+    test_expect_success "--batch-command session for $type content is correct" '
+	maybe_remove_timestamp "$batch_output" $no_ts >expect &&
+	maybe_remove_timestamp \
+		"$(test_write_lines "begin" "$sha1" "get contents" | git cat-file --batch-command)" \
+		$no_ts >actual &&
+	test_cmp expect actual
+    '
+
+    test_expect_success "--batch-command output of $type info is correct" '
+	echo "$sha1 $type $size" >expect &&
+	echo "info $sha1" | git cat-file --batch-command >actual &&
+	test_cmp expect actual
+    '
+
+    test_expect_success "--batch-command session for $type info is correct" '
+	echo "$sha1 $type $size" >expect &&
+	test_write_lines "begin" "$sha1" "get info" | git cat-file --batch-command >actual &&
+	test_cmp expect actual
+    '
+
     test_expect_success "custom --batch-check format" '
 	echo "$type $sha1" >expect &&
 	echo $sha1 | git cat-file --batch-check="%(objecttype) %(objectname)" >actual &&
@@ -141,6 +169,7 @@ test_expect_success '--batch-check without %(rest) considers whole line' '
 '
 
 tree_sha1=$(git write-tree)
+
stray newline addition.
quoted hunk ↗ jump to hunk
 tree_size=$(($(test_oid rawsz) + 13))
 tree_pretty_content="100644 blob $hello_sha1	hello"
 
@@ -175,7 +204,7 @@ test_expect_success \
     "Reach a blob from a tag pointing to it" \
     "test '$hello_content' = \"\$(git cat-file blob $tag_sha1)\""
 
-for batch in batch batch-check
+for batch in batch batch-check batch-command
 do
     for opt in t s e p
     do
@@ -281,6 +310,15 @@ test_expect_success "--batch-check with multiple sha1s gives correct format" '
     "$(echo_without_newline "$batch_check_input" | git cat-file --batch-check)"
 '
 
+test_expect_success "--batch-command with multiple sha1s gives correct format" '
+    echo "$batch_check_output" >expect &&
+    echo begin >input &&
+    echo_without_newline "$batch_check_input" >>input &&
+    echo "get info" >>input &&
+    git cat-file --batch-command <input >actual &&
+    test_cmp expect actual
+'
indentation with spaces, \t correctly used for the rest.
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