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[PATCH v12 12/12] ls-tree: support --object-only option for "git-ls-tree"

From
Teng Long <dyroneteng@gmail.com>
Date
Mar 4, 2022, 10:42 UTC
Message-ID
<55b1c4379d51c8254ac71a7b897d81bddd863143.1646390152.git.dyroneteng@gmail.com>
In-Reply-To
<cover.1646390152.git.dyroneteng@gmail.com>

'--object-only' is an alias for '--format=%(objectname)'. It cannot be used together other format-altering options like '--name-only', '--long' or '--format', they are mutually exclusive.

The "--name-only" option outputs <filepath> only. Likewise, <objectName> is another high frequency used field, so implement '--object-only' option will bring intuitive and clear semantics for this scenario. Using '--format=%(objectname)' we can achieve a similar effect, but the former is with a lower learning cost(without knowing the format requirement of '--format' option).

Even so, if a user is prefer to use "--format=%(objectname)", this is entirely welcome because they are not only equivalent in function, but also have almost identical performance. The reason is this commit also add the specific of "--format=%(objectname)" to the current fast-pathes (builtin formats) to avoid running unnecessary parsing mechanisms.

The following performance benchmarks are based on torvalds/linux.git:
  When hit the fast-path:
      Benchmark 1: /opt/git/ls-tree-oid-only/bin/git ls-tree -r --object-only HEAD
        Time (mean ± σ):      83.6 ms ±   2.0 ms    [User: 59.4 ms, System: 24.1 ms]
        Range (min … max):    80.4 ms …  87.2 ms    35 runs
      Benchmark 1: /opt/git/ls-tree-oid-only/bin/git ls-tree -r --format='%(objectname)' HEAD
        Time (mean ± σ):      84.1 ms ±   1.8 ms    [User: 61.7 ms, System: 22.3 ms]
        Range (min … max):    80.9 ms …  87.5 ms    35 runs
  But for a customized format, it will be slower:
       Benchmark 1: /opt/git/ls-tree-oid-only/bin/git ls-tree -r --format='oid: %(objectname)' HEAD
         Time (mean ± σ):      96.5 ms ±   2.5 ms    [User: 72.9 ms, System: 23.5 ms]
  	 Range (min … max):    93.1 ms … 104.1 ms    31 runs
Signed-off-by: Teng Long <dyroneteng@gmail.com>
---
 Documentation/git-ls-tree.txt | 11 ++++++++++-
 builtin/ls-tree.c             | 18 +++++++++++++++++-
 t/t3103-ls-tree-misc.sh       |  7 +++++--
 t/t3104-ls-tree-format.sh     | 19 +++++++++++++++++++
 4 files changed, 51 insertions(+), 4 deletions(-)
diff --git a/Documentation/git-ls-tree.txt b/Documentation/git-ls-tree.txt
index db29a9efb5..1aea998e72 100644
--- a/Documentation/git-ls-tree.txt
+++ b/Documentation/git-ls-tree.txt
@@ -10,7 +10,7 @@ SYNOPSIS
 --------
 [verse]
 'git ls-tree' [-d] [-r] [-t] [-l] [-z]
-	    [--name-only] [--name-status] [--full-name] [--full-tree] [--abbrev[=<n>]] [--format=<format>]
+	    [--name-only] [--name-status] [--object-only] [--full-name] [--full-tree] [--abbrev[=<n>]] [--format=<format>]
 	    <tree-ish> [<path>...]
 
 DESCRIPTION
@@ -59,6 +59,15 @@ OPTIONS
 --name-only::
 --name-status::
 	List only filenames (instead of the "long" output), one per line.
+	Cannot be combined with `--object-only`.
+
+--object-only::
+	List only names of the objects, one per line. Cannot be combined
+	with `--name-only` or `--name-status`.
+	This is equivalent to specifying `--format='%(objectname)'`, but
+	for both this option and that exact format the command takes a
+	hand-optimized codepath instead of going through the generic
+	formatting mechanism.
 
 --abbrev[=<n>]::
 	Instead of showing the full 40-byte hexadecimal object
diff --git a/builtin/ls-tree.c b/builtin/ls-tree.c
index a46fa73bb3..7da21d9963 100644
--- a/builtin/ls-tree.c
+++ b/builtin/ls-tree.c
@@ -20,6 +20,7 @@ static int line_termination = '\n';
 #define LS_SHOW_TREES (1 << 2)
 #define LS_NAME_ONLY (1 << 3)
 #define LS_SHOW_SIZE (1 << 4)
+#define LS_OBJECT_ONLY (1 << 5)
 static int abbrev;
 static int ls_options;
 static struct pathspec pathspec;
@@ -36,6 +37,7 @@ static const char *format;
 static const char *default_format = "%(objectmode) %(objecttype) %(objectname)%x09%(path)";
 static const char *long_format = "%(objectmode) %(objecttype) %(objectname) %(objectsize:padded)%x09%(path)";
 static const char *name_only_format = "%(path)";
+static const char *object_only_format = "%(objectname)";
 struct show_tree_data {
 	unsigned mode;
 	enum object_type type;
@@ -53,6 +55,7 @@ static const  char * const ls_tree_usage[] = {
 static enum mutx_option {
 	MODE_UNSPECIFIED = 0,
 	MODE_NAME_ONLY,
+	MODE_OBJECT_ONLY,
 	MODE_LONG,
 } cmdmode;
 
@@ -128,7 +131,10 @@ static int parse_shown_fields(unsigned int *shown_fields)
 		*shown_fields = FIELD_PATH_NAME;
 		return 0;
 	}
-
+	if (cmdmode == MODE_OBJECT_ONLY) {
+		*shown_fields = FIELD_OBJECT_NAME;
+		return 0;
+	}
 	if (!ls_options || (ls_options & LS_RECURSIVE)
 	    || (ls_options & LS_SHOW_TREES)
 	    || (ls_options & LS_TREE_ONLY))
@@ -257,6 +263,11 @@ static int show_tree(const struct object_id *oid, struct strbuf *base,
 			return recurse;
 	}
 
+	if (shown_fields == FIELD_OBJECT_NAME) {
+		printf("%s%c", find_unique_abbrev(oid, abbrev), line_termination);
+		return recurse;
+	}
+
 	if (shown_fields == FIELD_PATH_NAME) {
 		baselen = base->len;
 		strbuf_addstr(base, pathname);
@@ -295,6 +306,8 @@ int cmd_ls_tree(int argc, const char **argv, const char *prefix)
 			    MODE_NAME_ONLY),
 		OPT_CMDMODE(0, "name-status", &cmdmode, N_("list only filenames"),
 			    MODE_NAME_ONLY),
+		OPT_CMDMODE(0, "object-only", &cmdmode, N_("list only objects"),
+			    MODE_OBJECT_ONLY),
 		OPT_SET_INT(0, "full-name", &chomp_prefix,
 			    N_("use full path names"), 0),
 		OPT_BOOL(0, "full-tree", &full_tree,
@@ -363,6 +376,9 @@ int cmd_ls_tree(int argc, const char **argv, const char *prefix)
 	} else if (format && (!strcmp(format, name_only_format))) {
 		shown_fields = FIELD_PATH_NAME;
 		fn = show_tree;
+	} else if (format && (!strcmp(format, object_only_format))) {
+		shown_fields = FIELD_OBJECT_NAME;
+		fn = show_tree;
 	} else if (format)
 		fn = show_tree_fmt;
 
diff --git a/t/t3103-ls-tree-misc.sh b/t/t3103-ls-tree-misc.sh
index d9d7fa932f..d979c0df5d 100755
--- a/t/t3103-ls-tree-misc.sh
+++ b/t/t3103-ls-tree-misc.sh
@@ -25,11 +25,14 @@ test_expect_success 'ls-tree fails with non-zero exit code on broken tree' '
 
 for opts in \
 	"--name-only --long" \
-	"--name-status --long"
+	"--name-status --long" \
+	"--name-only --object-only" \
+	"--name-status --object-only" \
+	"--object-only --long" \
+	"--object-only --format"
 do
 	test_expect_success "usage: incompatible options: $opts" '
 		test_expect_code 129 git ls-tree $opts $tree
     '
 done
-
 test_done
diff --git a/t/t3104-ls-tree-format.sh b/t/t3104-ls-tree-format.sh
index e08c83dc47..b86941c202 100755
--- a/t/t3104-ls-tree-format.sh
+++ b/t/t3104-ls-tree-format.sh
@@ -46,6 +46,19 @@ test_expect_success 'ls-tree --format=<name-only-like>' '
 		"--name-only"
 '
 
+test_expect_success 'ls-tree --format=<object-only-like>' '
+	test_ls_tree_format \
+		"%(objectname)" \
+		"--object-only"
+'
+
+test_expect_success 'ls-tree --format=<object-only-like> --abbrev' '
+	test_ls_tree_format \
+		"%(objectname)" \
+		"--object-only --abbrev" \
+		"--abbrev"
+'
+
 test_expect_success 'ls-tree combine --format=<default-like> and -t' '
 	test_ls_tree_format \
 	"%(objectmode) %(objecttype) %(objectname)%x09%(path)" \
@@ -78,4 +91,10 @@ test_expect_success 'ls-tree hit fast-path with --format=<name-only-like>' '
 	git ls-tree --format="%(path)" -r HEAD >actual &&
 	test_cmp expect actual
 '
+
+test_expect_success 'ls-tree hit fast-path with --format=<object-only-like>' '
+	git ls-tree -r --object-only HEAD >expect &&
+	git ls-tree --format="%(objectname)" -r HEAD >actual &&
+	test_cmp expect actual
+'
 test_done

-- 
2.34.1.402.gef0f5bd184
Previous: Teng LongNext: Ævar Arnfjörð Bjarmason
Message 33 of 107 in “ls-tree: "--object-only" and "--format" opts”
  1. 00/13 ls-tree: "--object-only" and "--format" optsTeng Long, Feb 8, 2022
  2. 01/13 ls-tree: remove commented-out codeTeng Long, Feb 8, 2022
  3. 03/13 ls-tree: use "enum object_type", not {blob,tree,commit}_typeTeng Long, Feb 8, 2022
  4. 12/13 ls-tree: introduce function "fast_path()"Teng Long, Feb 8, 2022
  5. Ævar Arnfjörð BjarmasonFeb 19, 2022
  6. 13/13 ls-tree.c: support --object-only option for "git-ls-tree"Teng Long, Feb 8, 2022
  7. Ævar Arnfjörð BjarmasonFeb 19, 2022
  8. 04/13 ls-tree: use "size_t", not "int" for "struct strbuf"'s "len"Teng Long, Feb 8, 2022
  9. 02/13 ls-tree: add missing braces to "else" armsTeng Long, Feb 8, 2022
  10. 06/13 ls-tree: simplify nesting if/else logic in "show_tree()"Teng Long, Feb 8, 2022
  11. Ævar Arnfjörð BjarmasonFeb 19, 2022
  12. 05/13 ls-tree: rename "retval" to "recurse" in "show_tree()"Teng Long, Feb 8, 2022
  13. 07/13 ls-tree: fix "--name-only" and "--long" combined use bugTeng Long, Feb 8, 2022
  14. Ævar Arnfjörð BjarmasonFeb 19, 2022
  15. 08/13 ls-tree: slightly refactor `show_tree()`Teng Long, Feb 8, 2022
  16. Ævar Arnfjörð BjarmasonFeb 19, 2022
  17. 10/13 cocci: allow padding with `strbuf_addf()`Teng Long, Feb 8, 2022
  18. 09/13 ls-tree: introduce struct "show_tree_data"Teng Long, Feb 8, 2022
  19. 11/13 ls-tree.c: introduce "--format" optionTeng Long, Feb 8, 2022
  20. Ævar Arnfjörð BjarmasonFeb 19, 2022
  21. 00/12 ls-tree: "--object-only" and "--format" optsTeng Long, Mar 4, 2022
  22. 01/12 ls-tree: remove commented-out codeTeng Long, Mar 4, 2022
  23. 02/12 ls-tree: add missing braces to "else" armsTeng Long, Mar 4, 2022
  24. 03/12 ls-tree: use "enum object_type", not {blob,tree,commit}_typeTeng Long, Mar 4, 2022
  25. 04/12 ls-tree: use "size_t", not "int" for "struct strbuf"'s "len"Teng Long, Mar 4, 2022
  26. 05/12 ls-tree: rename "retval" to "recurse" in "show_tree()"Teng Long, Mar 4, 2022
  27. 06/12 ls-tree: simplify nesting if/else logic in "show_tree()"Teng Long, Mar 4, 2022
  28. 07/12 ls-tree: fix "--name-only" and "--long" combined use bugTeng Long, Mar 4, 2022
  29. 08/12 ls-tree: slightly refactor `show_tree()`Teng Long, Mar 4, 2022
  30. 09/12 ls-tree: introduce struct "show_tree_data"Teng Long, Mar 4, 2022
  31. 10/12 cocci: allow padding with `strbuf_addf()`Teng Long, Mar 4, 2022
  32. 11/12 ls-tree: introduce "--format" optionTeng Long, Mar 4, 2022
  33. 12/12 ls-tree: support --object-only option for "git-ls-tree"Teng Long, Mar 4, 2022
  34. 0/7 fixups/suggestions/musings for tl/ls-tree-oid-onlyÆvar Arnfjörð Bjarmason, Mar 10, 2022
  35. 1/7 ls-tree tests: add tests for --name-statusÆvar Arnfjörð Bjarmason, Mar 10, 2022
  36. 2/7 ls-tree tests: exhaustively test fast & slow path for --formatÆvar Arnfjörð Bjarmason, Mar 10, 2022
  37. 5/7 ls-tree: detect and error on --name-only --name-statusÆvar Arnfjörð Bjarmason, Mar 10, 2022
  38. 4/7 ls-tree: remove unused "MODE_UNSPECIFIED"Ævar Arnfjörð Bjarmason, Mar 10, 2022
  39. 3/7 ls-tree: remove dead labelsÆvar Arnfjörð Bjarmason, Mar 10, 2022
  40. 6/7 ls-tree: remove FIELD_*, just use MODE_*Ævar Arnfjörð Bjarmason, Mar 10, 2022
  41. 7/7 ls-tree: split up "fast path" callbacksÆvar Arnfjörð Bjarmason, Mar 10, 2022
  42. Teng LongMar 17, 2022
  43. Ævar Arnfjörð BjarmasonMar 17, 2022
  44. 00/16 ls-tree: "--object-only" and "--format" optsTeng Long, Mar 21, 2022
  45. 01/16 ls-tree: remove commented-out codeTeng Long, Mar 21, 2022
  46. 02/16 ls-tree: add missing braces to "else" armsTeng Long, Mar 21, 2022
  47. 03/16 ls-tree: use "enum object_type", not {blob,tree,commit}_typeTeng Long, Mar 21, 2022
  48. 04/16 ls-tree: use "size_t", not "int" for "struct strbuf"'s "len"Teng Long, Mar 21, 2022
  49. 05/16 ls-tree: rename "retval" to "recurse" in "show_tree()"Teng Long, Mar 21, 2022
  50. 06/16 ls-tree: simplify nesting if/else logic in "show_tree()"Teng Long, Mar 21, 2022
  51. 07/16 ls-tree: fix "--name-only" and "--long" combined use bugTeng Long, Mar 21, 2022
  52. 08/16 ls-tree: slightly refactor `show_tree()`Teng Long, Mar 21, 2022
  53. 09/16 ls-tree: introduce struct "show_tree_data"Teng Long, Mar 21, 2022
  54. 10/16 cocci: allow padding with `strbuf_addf()`Teng Long, Mar 21, 2022
  55. 11/16 ls-tree: introduce "--format" optionTeng Long, Mar 21, 2022
  56. Ævar Arnfjörð BjarmasonMar 21, 2022
  57. 12/16 ls-tree: support --object-only option for "git-ls-tree"Teng Long, Mar 21, 2022
  58. 13/16 ls-tree tests: add tests for --name-statusTeng Long, Mar 21, 2022
  59. Ævar Arnfjörð BjarmasonMar 21, 2022
  60. 14/16 ls-tree: detect and error on --name-only --name-statusTeng Long, Mar 21, 2022
  61. 15/16 ls-tree: remove FIELD_*, just use MODE_*Teng Long, Mar 21, 2022
  62. Ævar Arnfjörð BjarmasonMar 21, 2022
  63. 16/16 ls-tree: split up "fast path" callbacksTeng Long, Mar 21, 2022
  64. Ævar Arnfjörð BjarmasonMar 21, 2022
  65. Teng LongMar 23, 2022
  66. Junio C HamanoMar 21, 2022
  67. 00/15 ls-tree: "--object-only" and "--format" optsTeng Long, Mar 23, 2022
  68. 01/15 ls-tree tests: add tests for --name-statusTeng Long, Mar 23, 2022
  69. 02/15 ls-tree: remove commented-out codeTeng Long, Mar 23, 2022
  70. 03/15 ls-tree: add missing braces to "else" armsTeng Long, Mar 23, 2022
  71. 04/15 ls-tree: use "enum object_type", not {blob,tree,commit}_typeTeng Long, Mar 23, 2022
  72. 05/15 ls-tree: use "size_t", not "int" for "struct strbuf"'s "len"Teng Long, Mar 23, 2022
  73. 06/15 ls-tree: rename "retval" to "recurse" in "show_tree()"Teng Long, Mar 23, 2022
  74. 07/15 ls-tree: simplify nesting if/else logic in "show_tree()"Teng Long, Mar 23, 2022
  75. 08/15 ls-tree: fix "--name-only" and "--long" combined use bugTeng Long, Mar 23, 2022
  76. 09/15 ls-tree: slightly refactor `show_tree()`Teng Long, Mar 23, 2022
  77. 10/15 ls-tree: introduce struct "show_tree_data"Teng Long, Mar 23, 2022
  78. 11/15 cocci: allow padding with `strbuf_addf()`Teng Long, Mar 23, 2022
  79. 12/15 ls-tree: introduce "--format" optionTeng Long, Mar 23, 2022
  80. 13/15 ls-tree: support --object-only option for "git-ls-tree"Teng Long, Mar 23, 2022
  81. 14/15 ls-tree: detect and error on --name-only --name-statusTeng Long, Mar 23, 2022
  82. 15/15 ls-tree: split up "fast path" callbacksTeng Long, Mar 23, 2022
  83. Josh SteadmonApr 4, 2022
  84. ls-tree: `-l` should not imply recursive listingJosh Steadmon, Apr 4, 2022
  85. ls-tree: fix --long implying -r regression in 9c4d58ff2c3Ævar Arnfjörð Bjarmason, Apr 4, 2022
  86. Junio C HamanoApr 6, 2022
  87. Ævar Arnfjörð BjarmasonApr 6, 2022
  88. Junio C HamanoApr 6, 2022
  89. Ævar Arnfjörð BjarmasonApr 7, 2022
  90. Junio C HamanoApr 7, 2022
  91. ls-tree: test for the regression in 9c4d58ff2c3Ævar Arnfjörð Bjarmason, May 31, 2022
  92. Johannes SchindelinJun 2, 2022
  93. Junio C HamanoJun 2, 2022
  94. js/ci-github-workflow-markup output regression (was: [PATCH] ls-tree: test for the regression in 9c4d58ff2c3)Ævar Arnfjörð Bjarmason, Jun 3, 2022
  95. Junio C HamanoJun 3, 2022
  96. Ævar Arnfjörð BjarmasonJun 3, 2022
  97. Junio C HamanoJun 7, 2022
  98. Ævar Arnfjörð BjarmasonJun 7, 2022
  99. Johannes SchindelinJun 8, 2022
  100. Ævar Arnfjörð BjarmasonJun 9, 2022
  101. ls-tree: test for the regression in 9c4d58ff2c3Ævar Arnfjörð Bjarmason, Jun 3, 2022
  102. Johannes SchindelinJun 8, 2022
  103. Teng LongApr 7, 2022
  104. Junio C HamanoApr 6, 2022
  105. Junio C HamanoMar 23, 2022
  106. Teng LongMar 24, 2022
  107. Ævar Arnfjörð BjarmasonFeb 28, 2022

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