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[PATCH 18/27] [GSOC] ref-filter: use atom_type and merge two for loop in grab_person

From
ZheNing Hu via GitGitGadget <gitgitgadget@gmail.com>
Date
Aug 13, 2021, 08:23 UTC
Message-ID
<a908402fb520c88d5b99294926b8687a1a53015a.1628842990.git.gitgitgadget@gmail.com>
In-Reply-To
<pull.1016.git.1628842990.gitgitgadget@gmail.com>
From: ZheNing Hu <adlternative@gmail.com>

grab_person() uses string for atom type comparison, this is very inefficient, we can use atom_type to replace it. At the same time, we can merge the two for loops in grab_person() into one, this can reduce unnecessary traversal of the used_atom list.

With this patch, `git cat-file --batch` has a 2% performance improvement.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Hariom Verma <hariom18599@gmail.com>
Signed-off-by: ZheNing Hu <adlternative@gmail.com>
---
 ref-filter.c | 57 +++++++++++++++++-----------------------------------
 1 file changed, 18 insertions(+), 39 deletions(-)
diff --git a/ref-filter.c b/ref-filter.c
index 1251e062ff8..3ccb531e073 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -1307,63 +1307,42 @@ static void grab_date(const char *buf, struct atom_value *v, const char *atomnam
 }
 
 /* See grab_values */
-static void grab_person(const char *who, struct atom_value *val, int deref, void *buf)
+static void grab_person(enum atom_type type, struct atom_value *val, int deref, void *buf)
 {
 	int i;
+	const char *who = valid_atom[type].name;
 	int wholen = strlen(who);
 	const char *wholine = NULL;
 
 	for (i = 0; i < used_atom_cnt; i++) {
 		const char *name = used_atom[i].name;
+		enum atom_type atom_type = used_atom[i].atom_type;
 		struct atom_value *v = &val[i];
 		if (!!deref != (*name == '*'))
 			continue;
 		if (deref)
 			name++;
-		if (strncmp(who, name, wholen))
-			continue;
-		if (name[wholen] != 0 &&
-		    strcmp(name + wholen, "name") &&
-		    !starts_with(name + wholen, "email") &&
-		    !starts_with(name + wholen, "date"))
+		if ((atom_type < type || atom_type > type + 3) &&
+		    /*
+		    * For a tag or a commit object, if "creator" or "creatordate" is
+		    * requested, do something special.
+		    */
+		    ((atom_type != ATOM_CREATOR && atom_type != ATOM_CREATORDATE) ||
+		     ((atom_type == ATOM_CREATOR || atom_type == ATOM_CREATORDATE) &&
+		      type != ATOM_TAGGER && type != ATOM_COMMITTER)))
 			continue;
 		if (!wholine)
 			wholine = find_wholine(who, wholen, buf);
 		if (!wholine)
 			return; /* no point looking for it */
-		if (name[wholen] == 0)
+		if (atom_type == type || atom_type == ATOM_CREATOR)
 			v->s = copy_line(wholine);
-		else if (!strcmp(name + wholen, "name"))
+		else if (atom_type == type + 1)
 			v->s = copy_name(wholine);
-		else if (starts_with(name + wholen, "email"))
+		else if (atom_type == type + 2)
 			v->s = copy_email(wholine, &used_atom[i]);
-		else if (starts_with(name + wholen, "date"))
-			grab_date(wholine, v, name);
-	}
-
-	/*
-	 * For a tag or a commit object, if "creator" or "creatordate" is
-	 * requested, do something special.
-	 */
-	if (strcmp(who, "tagger") && strcmp(who, "committer"))
-		return; /* "author" for commit object is not wanted */
-	if (!wholine)
-		wholine = find_wholine(who, wholen, buf);
-	if (!wholine)
-		return;
-	for (i = 0; i < used_atom_cnt; i++) {
-		const char *name = used_atom[i].name;
-		enum atom_type atom_type = used_atom[i].atom_type;
-		struct atom_value *v = &val[i];
-		if (!!deref != (*name == '*'))
-			continue;
-		if (deref)
-			name++;
-
-		if (atom_type == ATOM_CREATORDATE)
+		else if (atom_type == type + 3 || atom_type == ATOM_CREATORDATE)
 			grab_date(wholine, v, name);
-		else if (atom_type == ATOM_CREATOR)
-			v->s = copy_line(wholine);
 	}
 }
 
@@ -1553,14 +1532,14 @@ static void grab_values(struct atom_value *val, int deref, struct object *obj, s
 		if (obj)
 			grab_tag_values(val, deref, obj);
 		grab_sub_body_contents(val, deref, data);
-		grab_person("tagger", val, deref, buf);
+		grab_person(ATOM_TAGGER, val, deref, buf);
 		break;
 	case OBJ_COMMIT:
 		if (obj)
 			grab_commit_values(val, deref, obj);
 		grab_sub_body_contents(val, deref, data);
-		grab_person("author", val, deref, buf);
-		grab_person("committer", val, deref, buf);
+		grab_person(ATOM_AUTHOR, val, deref, buf);
+		grab_person(ATOM_COMMITTER, val, deref, buf);
 		break;
 	case OBJ_TREE:
 		/* grab_tree_values(val, deref, obj, buf, sz); */
-- 
gitgitgadget
Previous: ZheNing Hu via GitGitGadgetNext: ZheNing Hu via GitGitGadget
Message 19 of 28 in “[GSOC] [RFC] cat-file: reuse ref-filter logic”
  1. 00/27 [GSOC] [RFC] cat-file: reuse ref-filter logicZheNing Hu via GitGitGadget, Aug 13, 2021
  2. 02/27 [GSOC] ref-filter: add %(raw) atomZheNing Hu via GitGitGadget, Aug 13, 2021
  3. 01/27 [GSOC] ref-filter: add obj-type check in grab contentsZheNing Hu via GitGitGadget, Aug 13, 2021
  4. 03/27 [GSOC] ref-filter: --format=%(raw) support --perlZheNing Hu via GitGitGadget, Aug 13, 2021
  5. 04/27 [GSOC] ref-filter: use non-const ref_format in *_atom_parser()ZheNing Hu via GitGitGadget, Aug 13, 2021
  6. 07/27 [GSOC] ref-filter: introduce free_ref_array_item_value() functionZheNing Hu via GitGitGadget, Aug 13, 2021
  7. 05/27 [GSOC] ref-filter: add %(rest) atomZheNing Hu via GitGitGadget, Aug 13, 2021
  8. 06/27 [GSOC] ref-filter: pass get_object() return value to their callersZheNing Hu via GitGitGadget, Aug 13, 2021
  9. 08/27 [GSOC] ref-filter: add cat_file_mode to ref_formatZheNing Hu via GitGitGadget, Aug 13, 2021
  10. 10/27 [GSOC] cat-file: add has_object_file() checkZheNing Hu via GitGitGadget, Aug 13, 2021
  11. 09/27 [GSOC] ref-filter: modify the error message and value in get_objectZheNing Hu via GitGitGadget, Aug 13, 2021
  12. 11/27 [GSOC] cat-file: change batch_objects parameter nameZheNing Hu via GitGitGadget, Aug 13, 2021
  13. 12/27 [GSOC] cat-file: create p1006-cat-file.shZheNing Hu via GitGitGadget, Aug 13, 2021
  14. 13/27 [GSOC] cat-file: reuse ref-filter logicZheNing Hu via GitGitGadget, Aug 13, 2021
  15. 14/27 [GSOC] cat-file: reuse err buf in batch_object_write()ZheNing Hu via GitGitGadget, Aug 13, 2021
  16. 15/27 [GSOC] cat-file: re-implement --textconv, --filters optionsZheNing Hu via GitGitGadget, Aug 13, 2021
  17. 16/27 [GSOC] ref-filter: remove grab_oid() functionZheNing Hu via GitGitGadget, Aug 13, 2021
  18. 17/27 [GSOC] ref-filter: performance optimization by skip parse_object_bufferZheNing Hu via GitGitGadget, Aug 13, 2021
  19. 18/27 [GSOC] ref-filter: use atom_type and merge two for loop in grab_personZheNing Hu via GitGitGadget, Aug 13, 2021
  20. 19/27 [GSOC] ref-filter: remove strlen from find_subposZheNing Hu via GitGitGadget, Aug 13, 2021
  21. 20/27 [GSOC] ref-filter: introducing xstrvfmt_len() and xstrfmt_len()ZheNing Hu via GitGitGadget, Aug 13, 2021
  22. 21/27 [GSOC] ref-filter: remove second parsing in format_ref_array_itemZheNing Hu via GitGitGadget, Aug 13, 2021
  23. 22/27 [GSOC] ref-filter: introduction ref_filter_slopbufZheNing Hu via GitGitGadget, Aug 13, 2021
  24. 23/27 [GSOC] ref-filter: add deref member to struct used_atomZheNing Hu via GitGitGadget, Aug 13, 2021
  25. 24/27 [GSOC] ref-filter: introduce symref_atom_parser()ZheNing Hu via GitGitGadget, Aug 13, 2021
  26. 25/27 [GSOC] ref-filter: use switch case instread of if elseZheNing Hu via GitGitGadget, Aug 13, 2021
  27. 27/27 [GSOC] ref-filter: add need_get_object_info flag to struct expand_dataZheNing Hu via GitGitGadget, Aug 13, 2021
  28. 26/27 [GSOC] ref-filter: reuse finnal buffer if no stack needZheNing Hu via GitGitGadget, Aug 13, 2021

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