git/list[1] front-page[2] threads[3] people[4] search[5] about
 

[PATCH] diff: use strncmp to check for "diff." prefix

From
RGRose via GitGitGadget <gitgitgadget@gmail.com>
Date
Dec 19, 2022, 16:33 UTC
Message-ID
<pull.1403.git.git.1671467624143.gitgitgadget@gmail.com>
From: Seija Kijin <doremylover123@gmail.com>

This would be a lot more efficient than checking for the full string, as so many of the accepted values begin with "diff."

This allows the computer to skip most checks if var did not start with diff at all.

It would also let us add more "diff." strings in the future without having to duplicate these 5 character so many times.

Signed-off-by: Seija Kijin <doremylover123@gmail.com>
---
    diff: use strncmp to check for "diff." prefix
    
    This would be a lot more efficient than checking for the full string, as
    so many of the accepted values begin with "diff."
    
    This allows the computer to skip most checks if var did not start with
    diff at all.
    
    It would also let us add more "diff." strings in the future without
    having to duplicate these 5 character so many times.
    
    Signed-off-by: Seija Kijin doremylover123@gmail.com
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1403%2FAtariDreams%2Fdiff-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1403/AtariDreams/diff-v1
Pull-Request: https://github.com/git/git/pull/1403
 diff.c | 158 +++++++++++++++++++++++++++++++--------------------------
 1 file changed, 87 insertions(+), 71 deletions(-)
diff --git a/diff.c b/diff.c
index 4dfe824c858..e0fddbe6009 100644
--- a/diff.c
+++ b/diff.c
@@ -345,82 +345,98 @@ static unsigned parse_color_moved_ws(const char *arg)
 
 int git_diff_ui_config(const char *var, const char *value, void *cb)
 {
-	if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
+	if (!strcmp(var, "color.diff")) {
 		diff_use_color_default = git_config_colorbool(var, value);
 		return 0;
 	}
-	if (!strcmp(var, "diff.colormoved")) {
-		int cm = parse_color_moved(value);
-		if (cm < 0)
-			return -1;
-		diff_color_moved_default = cm;
-		return 0;
-	}
-	if (!strcmp(var, "diff.colormovedws")) {
-		unsigned cm = parse_color_moved_ws(value);
-		if (cm & COLOR_MOVED_WS_ERROR)
-			return -1;
-		diff_color_moved_ws_default = cm;
-		return 0;
-	}
-	if (!strcmp(var, "diff.context")) {
-		diff_context_default = git_config_int(var, value);
-		if (diff_context_default < 0)
-			return -1;
-		return 0;
-	}
-	if (!strcmp(var, "diff.interhunkcontext")) {
-		diff_interhunk_context_default = git_config_int(var, value);
-		if (diff_interhunk_context_default < 0)
-			return -1;
-		return 0;
-	}
-	if (!strcmp(var, "diff.renames")) {
-		diff_detect_rename_default = git_config_rename(var, value);
-		return 0;
-	}
-	if (!strcmp(var, "diff.autorefreshindex")) {
-		diff_auto_refresh_index = git_config_bool(var, value);
-		return 0;
-	}
-	if (!strcmp(var, "diff.mnemonicprefix")) {
-		diff_mnemonic_prefix = git_config_bool(var, value);
-		return 0;
-	}
-	if (!strcmp(var, "diff.noprefix")) {
-		diff_no_prefix = git_config_bool(var, value);
-		return 0;
-	}
-	if (!strcmp(var, "diff.relative")) {
-		diff_relative = git_config_bool(var, value);
-		return 0;
-	}
-	if (!strcmp(var, "diff.statgraphwidth")) {
-		diff_stat_graph_width = git_config_int(var, value);
-		return 0;
-	}
-	if (!strcmp(var, "diff.external"))
-		return git_config_string(&external_diff_cmd_cfg, var, value);
-	if (!strcmp(var, "diff.wordregex"))
-		return git_config_string(&diff_word_regex_cfg, var, value);
-	if (!strcmp(var, "diff.orderfile"))
-		return git_config_pathname(&diff_order_file_cfg, var, value);
 
-	if (!strcmp(var, "diff.ignoresubmodules"))
-		handle_ignore_submodules_arg(&default_diff_options, value);
-
-	if (!strcmp(var, "diff.submodule")) {
-		if (parse_submodule_params(&default_diff_options, value))
-			warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
-				value);
-		return 0;
-	}
+	if (!strncmp(var, "diff.", 5)) {
+		const char *tmp = var + 5;
+		if (!strcmp(var, "color")) {
+			diff_use_color_default =
+				git_config_colorbool(var, value);
+			return 0;
+		}
+		if (!strcmp(tmp, "colormoved")) {
+			int cm = parse_color_moved(value);
+			if (cm < 0)
+				return -1;
+			diff_color_moved_default = cm;
+			return 0;
+		}
+		if (!strcmp(tmp, "colormovedws")) {
+			unsigned cm = parse_color_moved_ws(value);
+			if (cm & COLOR_MOVED_WS_ERROR)
+				return -1;
+			diff_color_moved_ws_default = cm;
+			return 0;
+		}
+		if (!strcmp(tmp, "context")) {
+			diff_context_default = git_config_int(var, value);
+			if (diff_context_default < 0)
+				return -1;
+			return 0;
+		}
+		if (!strcmp(tmp, "interhunkcontext")) {
+			diff_interhunk_context_default =
+				git_config_int(var, value);
+			if (diff_interhunk_context_default < 0)
+				return -1;
+			return 0;
+		}
+		if (!strcmp(tmp, "renames")) {
+			diff_detect_rename_default =
+				git_config_rename(var, value);
+			return 0;
+		}
+		if (!strcmp(tmp, "autorefreshindex")) {
+			diff_auto_refresh_index = git_config_bool(var, value);
+			return 0;
+		}
+		if (!strcmp(tmp, "mnemonicprefix")) {
+			diff_mnemonic_prefix = git_config_bool(var, value);
+			return 0;
+		}
+		if (!strcmp(tmp, "noprefix")) {
+			diff_no_prefix = git_config_bool(var, value);
+			return 0;
+		}
+		if (!strcmp(tmp, "relative")) {
+			diff_relative = git_config_bool(var, value);
+			return 0;
+		}
+		if (!strcmp(tmp, "statgraphwidth")) {
+			diff_stat_graph_width = git_config_int(var, value);
+			return 0;
+		}
+		if (!strcmp(tmp, "external"))
+			return git_config_string(&external_diff_cmd_cfg, var,
+						 value);
+		if (!strcmp(tmp, "wordregex"))
+			return git_config_string(&diff_word_regex_cfg, var,
+						 value);
+		if (!strcmp(tmp, "orderfile"))
+			return git_config_pathname(&diff_order_file_cfg, var,
+						   value);
+
+		if (!strcmp(tmp, "ignoresubmodules"))
+			handle_ignore_submodules_arg(&default_diff_options,
+						     value);
+
+		if (!strcmp(tmp, "submodule")) {
+			if (parse_submodule_params(&default_diff_options,
+						   value))
+				warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
+					value);
+			return 0;
+		}
 
-	if (!strcmp(var, "diff.algorithm")) {
-		diff_algorithm = parse_algorithm_value(value);
-		if (diff_algorithm < 0)
-			return -1;
-		return 0;
+		if (!strcmp(tmp, "algorithm")) {
+			diff_algorithm = parse_algorithm_value(value);
+			if (diff_algorithm < 0)
+				return -1;
+			return 0;
+		}
 	}
 
 	if (git_color_config(var, value, cb) < 0)

base-commit: 7c2ef319c52c4997256f5807564523dfd4acdfc7

-- 
gitgitgadget
Next: Ævar Arnfjörð Bjarmason
Message 1 of 2 in “diff: use strncmp to check for "diff." prefix”
  1. diff: use strncmp to check for "diff." prefixRose via GitGitGadget, Dec 19, 2022
  2. Ævar Arnfjörð BjarmasonDec 19, 2022

Read the whole thread, see it on lore, or plain text.

$ cat FOOTERMessages come from the public archive at lore.kernel.org/git, fetched every hour. The front page is chosen and written each morning by an AI editor and can be wrong; the threads themselves are the record. About and API. For agents: an MCP server at https://gitlist.dev/mcp, and any thread, story or person page as Markdown by adding .md to its URL (or sending Accept: text/markdown). Details in /llms.txt.