Merge branch 'ps/cat-file-null-output' into next

"git cat-file --batch" and friends learned "-Z" that uses NUL
delimiter for both input and output.

* ps/cat-file-null-output:
  cat-file: add option '-Z' that delimits input and output with NUL
  cat-file: simplify reading from standard input
  strbuf: provide CRLF-aware helper to read until a specified delimiter
  t1006: modernize test style to use `test_cmp`
  t1006: don't strip timestamps from expected results

Documentation/git-cat-file.txt

@@ -14,7 +14,7 @@ SYNOPSIS
 'git cat-file' (-t | -s) [--allow-unknown-type] <object>
 'git cat-file' (--batch | --batch-check | --batch-command) [--batch-all-objects]
  [--buffer] [--follow-symlinks] [--unordered]
- [--textconv | --filters] [-z]
+ [--textconv | --filters] [-Z]
 'git cat-file' (--textconv | --filters)
  [<rev>:<path|tree-ish> | --path=<path|tree-ish> <rev>]
 
@@ -243,10 +243,16 @@ respectively print:
  /etc/passwd
 --
 
+-Z::
+ Only meaningful with `--batch`, `--batch-check`, or
+ `--batch-command`; input and output is NUL-delimited instead of
+ newline-delimited.
+
 -z::
  Only meaningful with `--batch`, `--batch-check`, or
  `--batch-command`; input is NUL-delimited instead of
- newline-delimited.
+ newline-delimited. This option is deprecated in favor of
+ `-Z` as the output can otherwise be ambiguous.
 
 
 OUTPUT
@@ -384,6 +390,11 @@ notdir SP <size> LF
 is printed when, during symlink resolution, a file is used as a
 directory name.
 
+Alternatively, when `-Z` is passed, the line feeds in any of the above examples
+are replaced with NUL terminators. This ensures that output will be parsable if
+the output itself would contain a linefeed and is thus recommended for
+scripting purposes.
+
 CAVEATS
 -------
 

builtin/cat-file.c

@@ -41,7 +41,8 @@ struct batch_options {
  int all_objects;
  int unordered;
  int transform_mode; /* may be 'w' or 'c' for --filters or --textconv */
- int nul_terminated;
+ char input_delim;
+ char output_delim;
  const char *format;
 };
 
@@ -436,11 +437,12 @@ static void print_object_or_die(struct batch_options *opt, struct expand_data *d
  }
 }
 
-static void print_default_format(struct strbuf *scratch, struct expand_data *data)
+static void print_default_format(struct strbuf *scratch, struct expand_data *data,
+ struct batch_options *opt)
 {
- strbuf_addf(scratch, "%s %s %"PRIuMAX"\n", oid_to_hex(&data->oid),
+ strbuf_addf(scratch, "%s %s %"PRIuMAX"%c", oid_to_hex(&data->oid),
  type_name(data->type),
- (uintmax_t)data->size);
+ (uintmax_t)data->size, opt->output_delim);
 }
 
 /*
@@ -469,8 +471,8 @@ static void batch_object_write(const char *obj_name,
  &data->oid, &data->info,
  OBJECT_INFO_LOOKUP_REPLACE);
  if (ret < 0) {
- printf("%s missing\n",
- obj_name ? obj_name : oid_to_hex(&data->oid));
+ printf("%s missing%c",
+ obj_name ? obj_name : oid_to_hex(&data->oid), opt->output_delim);
  fflush(stdout);
  return;
  }
@@ -491,17 +493,17 @@ static void batch_object_write(const char *obj_name,
  strbuf_reset(scratch);
 
  if (!opt->format) {
- print_default_format(scratch, data);
+ print_default_format(scratch, data, opt);
  } else {
  strbuf_expand(scratch, opt->format, expand_format, data);
- strbuf_addch(scratch, '\n');
+ strbuf_addch(scratch, opt->output_delim);
  }
 
  batch_write(opt, scratch->buf, scratch->len);
 
  if (opt->batch_mode == BATCH_MODE_CONTENTS) {
  print_object_or_die(opt, data);
- batch_write(opt, "\n", 1);
+ batch_write(opt, &opt->output_delim, 1);
  }
 }
 
@@ -519,22 +521,25 @@ static void batch_one_object(const char *obj_name,
  if (result != FOUND) {
  switch (result) {
  case MISSING_OBJECT:
- printf("%s missing\n", obj_name);
+ printf("%s missing%c", obj_name, opt->output_delim);
  break;
  case SHORT_NAME_AMBIGUOUS:
- printf("%s ambiguous\n", obj_name);
+ printf("%s ambiguous%c", obj_name, opt->output_delim);
  break;
  case DANGLING_SYMLINK:
- printf("dangling %"PRIuMAX"\n%s\n",
- (uintmax_t)strlen(obj_name), obj_name);
+ printf("dangling %"PRIuMAX"%c%s%c",
+ (uintmax_t)strlen(obj_name),
+ opt->output_delim, obj_name, opt->output_delim);
  break;
  case SYMLINK_LOOP:
- printf("loop %"PRIuMAX"\n%s\n",
- (uintmax_t)strlen(obj_name), obj_name);
+ printf("loop %"PRIuMAX"%c%s%c",
+ (uintmax_t)strlen(obj_name),
+ opt->output_delim, obj_name, opt->output_delim);
  break;
  case NOT_DIR:
- printf("notdir %"PRIuMAX"\n%s\n",
- (uintmax_t)strlen(obj_name), obj_name);
+ printf("notdir %"PRIuMAX"%c%s%c",
+ (uintmax_t)strlen(obj_name),
+ opt->output_delim, obj_name, opt->output_delim);
  break;
  default:
  BUG("unknown get_sha1_with_context result %d\n",
@@ -546,9 +551,9 @@ static void batch_one_object(const char *obj_name,
  }
 
  if (ctx.mode == 0) {
- printf("symlink %"PRIuMAX"\n%s\n",
+ printf("symlink %"PRIuMAX"%c%s%c",
  (uintmax_t)ctx.symlink_path.len,
- ctx.symlink_path.buf);
+ opt->output_delim, ctx.symlink_path.buf, opt->output_delim);
  fflush(stdout);
  return;
  }
@@ -693,20 +698,12 @@ static void batch_objects_command(struct batch_options *opt,
  struct queued_cmd *queued_cmd = NULL;
  size_t alloc = 0, nr = 0;
 
- while (1) {
- int i, ret;
+ while (strbuf_getdelim_strip_crlf(&input, stdin, opt->input_delim) != EOF) {
+ int i;
  const struct parse_cmd *cmd = NULL;
  const char *p = NULL, *cmd_end;
  struct queued_cmd call = {0};
 
- if (opt->nul_terminated)
- ret = strbuf_getline_nul(&input, stdin);
- else
- ret = strbuf_getline(&input, stdin);
-
- if (ret)
- break;
-
  if (!input.len)
  die(_("empty command in input"));
  if (isspace(*input.buf))
@@ -850,16 +847,7 @@ static int batch_objects(struct batch_options *opt)
  goto cleanup;
  }
 
- while (1) {
- int ret;
- if (opt->nul_terminated)
- ret = strbuf_getline_nul(&input, stdin);
- else
- ret = strbuf_getline(&input, stdin);
-
- if (ret == EOF)
- break;
-
+ while (strbuf_getdelim_strip_crlf(&input, stdin, opt->input_delim) != EOF) {
  if (data.split_on_whitespace) {
  /*
  * Split at first whitespace, tying off the beginning
@@ -928,14 +916,16 @@ int cmd_cat_file(int argc, const char **argv, const char *prefix)
  const char *exp_type = NULL, *obj_name = NULL;
  struct batch_options batch = {0};
  int unknown_type = 0;
+ int input_nul_terminated = 0;
+ int nul_terminated = 0;
 
  const char * const usage[] = {
  N_("git cat-file <type> <object>"),
  N_("git cat-file (-e | -p) <object>"),
  N_("git cat-file (-t | -s) [--allow-unknown-type] <object>"),
  N_("git cat-file (--batch | --batch-check | --batch-command) [--batch-all-objects]\n"
  " [--buffer] [--follow-symlinks] [--unordered]\n"
- " [--textconv | --filters] [-z]"),
+ " [--textconv | --filters] [-Z]"),
  N_("git cat-file (--textconv | --filters)\n"
  " [<rev>:<path|tree-ish> | --path=<path|tree-ish> <rev>]"),
  NULL
@@ -964,7 +954,9 @@ int cmd_cat_file(int argc, const char **argv, const char *prefix)
  N_("like --batch, but don't emit <contents>"),
  PARSE_OPT_OPTARG | PARSE_OPT_NONEG,
  batch_option_callback),
- OPT_BOOL('z', NULL, &batch.nul_terminated, N_("stdin is NUL-terminated")),
+ OPT_BOOL_F('z', NULL, &input_nul_terminated, N_("stdin is NUL-terminated"),
+ PARSE_OPT_HIDDEN),
+ OPT_BOOL('Z', NULL, &nul_terminated, N_("stdin and stdout is NUL-terminated")),
  OPT_CALLBACK_F(0, "batch-command", &batch, N_("format"),
  N_("read commands from stdin"),
  PARSE_OPT_OPTARG | PARSE_OPT_NONEG,
@@ -1023,9 +1015,18 @@ int cmd_cat_file(int argc, const char **argv, const char *prefix)
  else if (batch.all_objects)
  usage_msg_optf(_("'%s' requires a batch mode"), usage, options,
  "--batch-all-objects");
- else if (batch.nul_terminated)
+ else if (input_nul_terminated)
  usage_msg_optf(_("'%s' requires a batch mode"), usage, options,
  "-z");
+ else if (nul_terminated)
+ usage_msg_optf(_("'%s' requires a batch mode"), usage, options,
+ "-Z");
+
+ batch.input_delim = batch.output_delim = '\n';
+ if (input_nul_terminated)
+ batch.input_delim = '\0';
+ if (nul_terminated)
+ batch.input_delim = batch.output_delim = '\0';
 
  /* Batch defaults */
  if (batch.buffer_output < 0)

strbuf.c

@@ -722,18 +722,23 @@ static int strbuf_getdelim(struct strbuf *sb, FILE *fp, int term)
  return 0;
 }
 
-int strbuf_getline(struct strbuf *sb, FILE *fp)
+int strbuf_getdelim_strip_crlf(struct strbuf *sb, FILE *fp, int term)
 {
- if (strbuf_getwholeline(sb, fp, '\n'))
+ if (strbuf_getwholeline(sb, fp, term))
  return EOF;
- if (sb->buf[sb->len - 1] == '\n') {
+ if (term == '\n' && sb->buf[sb->len - 1] == '\n') {
  strbuf_setlen(sb, sb->len - 1);
  if (sb->len && sb->buf[sb->len - 1] == '\r')
  strbuf_setlen(sb, sb->len - 1);
  }
  return 0;
 }
 
+int strbuf_getline(struct strbuf *sb, FILE *fp)
+{
+ return strbuf_getdelim_strip_crlf(sb, fp, '\n');
+}
+
 int strbuf_getline_lf(struct strbuf *sb, FILE *fp)
 {
  return strbuf_getdelim(sb, fp, '\n');

strbuf.h

@@ -471,6 +471,18 @@ int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint);
  */
 ssize_t strbuf_write(struct strbuf *sb, FILE *stream);
 
+/**
+ * Read from a FILE * until the specified terminator is encountered,
+ * overwriting the existing contents of the strbuf.
+ *
+ * Reading stops after the terminator or at EOF. The terminator is
+ * removed from the buffer before returning. If the terminator is LF
+ * and if it is preceded by a CR, then the whole CRLF is stripped.
+ * Returns 0 unless there was nothing left before EOF, in which case
+ * it returns `EOF`.
+ */
+int strbuf_getdelim_strip_crlf(struct strbuf *sb, FILE *fp, int term);
+
 /**
  * Read a line from a FILE *, overwriting the existing contents of
  * the strbuf. The strbuf_getline*() family of functions share