[PATCH v2 01/11] Add and use generic name->id mapping code for color slot parsing

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

Instead of hard coding the name-to-id mapping in C code, keep it in an
array and use a common function to do the parsing. This reduces code
and also allows us to list all possible color slots later.

This starts using C99 designated initializers more for convenience
(the first designated initializers have been introduced in builtin/clean.c
for some time without complaints)

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 builtin/branch.c | 28 +++++++++----------------
 builtin/clean.c  | 28 +++++++++----------------
 builtin/commit.c | 33 ++++++++++++++----------------
 config.c         | 13 ++++++++++++
 config.h         |  4 ++++
 diff.c           | 53 +++++++++++++++++++-----------------------------
 log-tree.c       | 35 ++++++++------------------------
 7 files changed, 82 insertions(+), 112 deletions(-)

diff --git a/builtin/branch.c b/builtin/branch.c
index f85d3de531..09232576b6 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -55,26 +55,18 @@ enum color_branch {
 	BRANCH_COLOR_UPSTREAM = 5
 };
 
+static const char *color_branch_slots[] = {
+	[BRANCH_COLOR_RESET]	= "reset",
+	[BRANCH_COLOR_PLAIN]	= "plain",
+	[BRANCH_COLOR_REMOTE]	= "remote",
+	[BRANCH_COLOR_LOCAL]	= "local",
+	[BRANCH_COLOR_CURRENT]	= "current",
+	[BRANCH_COLOR_UPSTREAM] = "upstream",
+};
+
 static struct string_list output = STRING_LIST_INIT_DUP;
 static unsigned int colopts;
 
-static int parse_branch_color_slot(const char *slot)
-{
-	if (!strcasecmp(slot, "plain"))
-		return BRANCH_COLOR_PLAIN;
-	if (!strcasecmp(slot, "reset"))
-		return BRANCH_COLOR_RESET;
-	if (!strcasecmp(slot, "remote"))
-		return BRANCH_COLOR_REMOTE;
-	if (!strcasecmp(slot, "local"))
-		return BRANCH_COLOR_LOCAL;
-	if (!strcasecmp(slot, "current"))
-		return BRANCH_COLOR_CURRENT;
-	if (!strcasecmp(slot, "upstream"))
-		return BRANCH_COLOR_UPSTREAM;
-	return -1;
-}
-
 static int git_branch_config(const char *var, const char *value, void *cb)
 {
 	const char *slot_name;
@@ -86,7 +78,7 @@ static int git_branch_config(const char *var, const char *value, void *cb)
 		return 0;
 	}
 	if (skip_prefix(var, "color.branch.", &slot_name)) {
-		int slot = parse_branch_color_slot(slot_name);
+		int slot = LOOKUP_CONFIG(color_branch_slots, slot_name);
 		if (slot < 0)
 			return 0;
 		if (!value)
diff --git a/builtin/clean.c b/builtin/clean.c
index fad533a0a7..0ccd95e693 100644
--- a/builtin/clean.c
+++ b/builtin/clean.c
@@ -42,6 +42,15 @@ enum color_clean {
 	CLEAN_COLOR_ERROR = 5
 };
 
+static const char *color_interactive_slots[] = {
+	[CLEAN_COLOR_ERROR]  = "error",
+	[CLEAN_COLOR_HEADER] = "header",
+	[CLEAN_COLOR_HELP]   = "help",
+	[CLEAN_COLOR_PLAIN]  = "plain",
+	[CLEAN_COLOR_PROMPT] = "prompt",
+	[CLEAN_COLOR_RESET]  = "reset",
+};
+
 static int clean_use_color = -1;
 static char clean_colors[][COLOR_MAXLEN] = {
 	[CLEAN_COLOR_ERROR] = GIT_COLOR_BOLD_RED,
@@ -82,23 +91,6 @@ struct menu_stuff {
 	void *stuff;
 };
 
-static int parse_clean_color_slot(const char *var)
-{
-	if (!strcasecmp(var, "reset"))
-		return CLEAN_COLOR_RESET;
-	if (!strcasecmp(var, "plain"))
-		return CLEAN_COLOR_PLAIN;
-	if (!strcasecmp(var, "prompt"))
-		return CLEAN_COLOR_PROMPT;
-	if (!strcasecmp(var, "header"))
-		return CLEAN_COLOR_HEADER;
-	if (!strcasecmp(var, "help"))
-		return CLEAN_COLOR_HELP;
-	if (!strcasecmp(var, "error"))
-		return CLEAN_COLOR_ERROR;
-	return -1;
-}
-
 static int git_clean_config(const char *var, const char *value, void *cb)
 {
 	const char *slot_name;
@@ -113,7 +105,7 @@ static int git_clean_config(const char *var, const char *value, void *cb)
 		return 0;
 	}
 	if (skip_prefix(var, "color.interactive.", &slot_name)) {
-		int slot = parse_clean_color_slot(slot_name);
+		int slot = LOOKUP_CONFIG(color_interactive_slots, slot_name);
 		if (slot < 0)
 			return 0;
 		if (!value)
diff --git a/builtin/commit.c b/builtin/commit.c
index a842fea666..2b43a6c48a 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -66,6 +66,18 @@ N_("If you wish to skip this commit, use:\n"
 "Then \"git cherry-pick --continue\" will resume cherry-picking\n"
 "the remaining commits.\n");
 
+static const char *color_status_slots[] = {
+	[WT_STATUS_HEADER]	  = "header",
+	[WT_STATUS_UPDATED]	  = "updated",
+	[WT_STATUS_CHANGED]	  = "changed",
+	[WT_STATUS_UNTRACKED]	  = "untracked",
+	[WT_STATUS_NOBRANCH]	  = "noBranch",
+	[WT_STATUS_UNMERGED]	  = "unmerged",
+	[WT_STATUS_LOCAL_BRANCH]  = "localBranch",
+	[WT_STATUS_REMOTE_BRANCH] = "remoteBranch",
+	[WT_STATUS_ONBRANCH]	  = "branch",
+};
+
 static const char *use_message_buffer;
 static struct lock_file index_lock; /* real index */
 static struct lock_file false_lock; /* used only for partial commits */
@@ -1185,25 +1197,10 @@ static int dry_run_commit(int argc, const char **argv, const char *prefix,
 
 static int parse_status_slot(const char *slot)
 {
-	if (!strcasecmp(slot, "header"))
-		return WT_STATUS_HEADER;
-	if (!strcasecmp(slot, "branch"))
-		return WT_STATUS_ONBRANCH;
-	if (!strcasecmp(slot, "updated") || !strcasecmp(slot, "added"))
+	if (!strcasecmp(slot, "added"))
 		return WT_STATUS_UPDATED;
-	if (!strcasecmp(slot, "changed"))
-		return WT_STATUS_CHANGED;
-	if (!strcasecmp(slot, "untracked"))
-		return WT_STATUS_UNTRACKED;
-	if (!strcasecmp(slot, "nobranch"))
-		return WT_STATUS_NOBRANCH;
-	if (!strcasecmp(slot, "unmerged"))
-		return WT_STATUS_UNMERGED;
-	if (!strcasecmp(slot, "localBranch"))
-		return WT_STATUS_LOCAL_BRANCH;
-	if (!strcasecmp(slot, "remoteBranch"))
-		return WT_STATUS_REMOTE_BRANCH;
-	return -1;
+
+	return LOOKUP_CONFIG(color_status_slots, slot);
 }
 
 static int git_status_config(const char *k, const char *v, void *cb)
diff --git a/config.c b/config.c
index fbbf0f8e9f..a0a6ae1980 100644
--- a/config.c
+++ b/config.c
@@ -3245,3 +3245,16 @@ enum config_scope current_config_scope(void)
 	else
 		return current_parsing_scope;
 }
+
+int lookup_config(const char **mapping, int nr_mapping, const char *var)
+{
+	int i;
+
+	for (i = 0; i < nr_mapping; i++) {
+		const char *name = mapping[i];
+
+		if (name && !strcasecmp(var, name))
+			return i;
+	}
+	return -1;
+}
diff --git a/config.h b/config.h
index cdac2fc73e..626d4654bd 100644
--- a/config.h
+++ b/config.h
@@ -257,4 +257,8 @@ struct key_value_info {
 extern NORETURN void git_die_config(const char *key, const char *err, ...) __attribute__((format(printf, 2, 3)));
 extern NORETURN void git_die_config_linenr(const char *key, const char *filename, int linenr);
 
+#define LOOKUP_CONFIG(mapping, var) \
+	lookup_config(mapping, ARRAY_SIZE(mapping), var)
+int lookup_config(const char **mapping, int nr_mapping, const char *var);
+
 #endif /* CONFIG_H */
diff --git a/diff.c b/diff.c
index efa6c1b82f..2e5e1404a5 100644
--- a/diff.c
+++ b/diff.c
@@ -69,6 +69,25 @@ static char diff_colors[][COLOR_MAXLEN] = {
 	GIT_COLOR_FAINT_ITALIC,	/* NEW_MOVED_ALTERNATIVE_DIM */
 };
 
+static const char *color_diff_slots[] = {
+	[DIFF_CONTEXT]		      = "context",
+	[DIFF_METAINFO]		      = "meta",
+	[DIFF_FRAGINFO]		      = "frag",
+	[DIFF_FILE_OLD]		      = "old",
+	[DIFF_FILE_NEW]		      = "new",
+	[DIFF_COMMIT]		      = "commit",
+	[DIFF_WHITESPACE]	      = "whitespace",
+	[DIFF_FUNCINFO]		      = "func",
+	[DIFF_FILE_OLD_MOVED]	      = "oldMoved",
+	[DIFF_FILE_OLD_MOVED_ALT]     = "oldMovedAlternative",
+	[DIFF_FILE_OLD_MOVED_DIM]     = "oldMovedDimmed",
+	[DIFF_FILE_OLD_MOVED_ALT_DIM] = "oldMovedAlternativeDimmed",
+	[DIFF_FILE_NEW_MOVED]	      = "newMoved",
+	[DIFF_FILE_NEW_MOVED_ALT]     = "newMovedAlternative",
+	[DIFF_FILE_NEW_MOVED_DIM]     = "newMovedDimmed",
+	[DIFF_FILE_NEW_MOVED_ALT_DIM] = "newMovedAlternativeDimmed",
+};
+
 static NORETURN void die_want_option(const char *option_name)
 {
 	die(_("option '%s' requires a value"), option_name);
@@ -76,39 +95,9 @@ static NORETURN void die_want_option(const char *option_name)
 
 static int parse_diff_color_slot(const char *var)
 {
-	if (!strcasecmp(var, "context") || !strcasecmp(var, "plain"))
+	if (!strcasecmp(var, "plain"))
 		return DIFF_CONTEXT;
-	if (!strcasecmp(var, "meta"))
-		return DIFF_METAINFO;
-	if (!strcasecmp(var, "frag"))
-		return DIFF_FRAGINFO;
-	if (!strcasecmp(var, "old"))
-		return DIFF_FILE_OLD;
-	if (!strcasecmp(var, "new"))
-		return DIFF_FILE_NEW;
-	if (!strcasecmp(var, "commit"))
-		return DIFF_COMMIT;
-	if (!strcasecmp(var, "whitespace"))
-		return DIFF_WHITESPACE;
-	if (!strcasecmp(var, "func"))
-		return DIFF_FUNCINFO;
-	if (!strcasecmp(var, "oldmoved"))
-		return DIFF_FILE_OLD_MOVED;
-	if (!strcasecmp(var, "oldmovedalternative"))
-		return DIFF_FILE_OLD_MOVED_ALT;
-	if (!strcasecmp(var, "oldmoveddimmed"))
-		return DIFF_FILE_OLD_MOVED_DIM;
-	if (!strcasecmp(var, "oldmovedalternativedimmed"))
-		return DIFF_FILE_OLD_MOVED_ALT_DIM;
-	if (!strcasecmp(var, "newmoved"))
-		return DIFF_FILE_NEW_MOVED;
-	if (!strcasecmp(var, "newmovedalternative"))
-		return DIFF_FILE_NEW_MOVED_ALT;
-	if (!strcasecmp(var, "newmoveddimmed"))
-		return DIFF_FILE_NEW_MOVED_DIM;
-	if (!strcasecmp(var, "newmovedalternativedimmed"))
-		return DIFF_FILE_NEW_MOVED_ALT_DIM;
-	return -1;
+	return LOOKUP_CONFIG(color_diff_slots, var);
 }
 
 static int parse_dirstat_params(struct diff_options *options, const char *params_string,
diff --git a/log-tree.c b/log-tree.c
index 0b97de5e87..33be7f7a3d 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -27,6 +27,14 @@ static char decoration_colors[][COLOR_MAXLEN] = {
 	GIT_COLOR_BOLD_BLUE,	/* GRAFTED */
 };
 
+static const char *color_decorate_slots[] = {
+	[DECORATION_REF_LOCAL]	= "branch",
+	[DECORATION_REF_REMOTE] = "remoteBranch",
+	[DECORATION_REF_TAG]	= "tag",
+	[DECORATION_REF_STASH]	= "stash",
+	[DECORATION_REF_HEAD]	= "HEAD",
+};
+
 static const char *decorate_get_color(int decorate_use_color, enum decoration_type ix)
 {
 	if (want_color(decorate_use_color))
@@ -34,34 +42,9 @@ static const char *decorate_get_color(int decorate_use_color, enum decoration_ty
 	return "";
 }
 
-static int parse_decorate_color_slot(const char *slot)
-{
-	/*
-	 * We're comparing with 'ignore-case' on
-	 * (because config.c sets them all tolower),
-	 * but let's match the letters in the literal
-	 * string values here with how they are
-	 * documented in Documentation/config.txt, for
-	 * consistency.
-	 *
-	 * We love being consistent, don't we?
-	 */
-	if (!strcasecmp(slot, "branch"))
-		return DECORATION_REF_LOCAL;
-	if (!strcasecmp(slot, "remoteBranch"))
-		return DECORATION_REF_REMOTE;
-	if (!strcasecmp(slot, "tag"))
-		return DECORATION_REF_TAG;
-	if (!strcasecmp(slot, "stash"))
-		return DECORATION_REF_STASH;
-	if (!strcasecmp(slot, "HEAD"))
-		return DECORATION_REF_HEAD;
-	return -1;
-}
-
 int parse_decorate_color_config(const char *var, const char *slot_name, const char *value)
 {
-	int slot = parse_decorate_color_slot(slot_name);
+	int slot = LOOKUP_CONFIG(color_decorate_slots, slot_name);
 	if (slot < 0)
 		return 0;
 	if (!value)
-- 
2.17.0.705.g3525833791