Merge branch 'bc/more-git-var'

Add more "git var" for toolsmiths to learn various locations Git is
configured with either via the configuration or hardcoded defaults.

* bc/more-git-var:
  var: add config file locations
  var: add attributes files locations
  attr: expose and rename accessor functions
  var: adjust memory allocation for strings
  var: format variable structure with C99 initializers
  var: add support for listing the shell
  t: add a function to check executable bit
  var: mark unused parameters in git_var callbacks

builtin/var.c

@@ -4,60 +4,188 @@
  * Copyright (C) Eric Biederman, 2005
  */
 #include "builtin.h"
+#include "attr.h"
 #include "config.h"
 #include "editor.h"
 #include "ident.h"
 #include "pager.h"
 #include "refs.h"
+#include "path.h"
+#include "strbuf.h"
 
 static const char var_usage[] = "git var (-l | <variable>)";
 
-static const char *editor(int flag)
+static char *committer(int ident_flag)
 {
-	return git_editor();
+	return xstrdup_or_null(git_committer_info(ident_flag));
 }
 
-static const char *sequence_editor(int flag)
+static char *author(int ident_flag)
 {
-	return git_sequence_editor();
+	return xstrdup_or_null(git_author_info(ident_flag));
 }
 
-static const char *pager(int flag)
+static char *editor(int ident_flag UNUSED)
+{
+	return xstrdup_or_null(git_editor());
+}
+
+static char *sequence_editor(int ident_flag UNUSED)
+{
+	return xstrdup_or_null(git_sequence_editor());
+}
+
+static char *pager(int ident_flag UNUSED)
 {
 	const char *pgm = git_pager(1);
 
 	if (!pgm)
 		pgm = "cat";
-	return pgm;
+	return xstrdup(pgm);
 }
 
-static const char *default_branch(int flag)
+static char *default_branch(int ident_flag UNUSED)
 {
-	return git_default_branch_name(1);
+	return xstrdup_or_null(git_default_branch_name(1));
+}
+
+static char *shell_path(int ident_flag UNUSED)
+{
+	return xstrdup(SHELL_PATH);
+}
+
+static char *git_attr_val_system(int ident_flag UNUSED)
+{
+	if (git_attr_system_is_enabled()) {
+		char *file = xstrdup(git_attr_system_file());
+		normalize_path_copy(file, file);
+		return file;
+	}
+	return NULL;
+}
+
+static char *git_attr_val_global(int ident_flag UNUSED)
+{
+	char *file = xstrdup(git_attr_global_file());
+	if (file) {
+		normalize_path_copy(file, file);
+		return file;
+	}
+	return NULL;
+}
+
+static char *git_config_val_system(int ident_flag UNUSED)
+{
+	if (git_config_system()) {
+		char *file = git_system_config();
+		normalize_path_copy(file, file);
+		return file;
+	}
+	return NULL;
+}
+
+static char *git_config_val_global(int ident_flag UNUSED)
+{
+	struct strbuf buf = STRBUF_INIT;
+	char *user, *xdg;
+	size_t unused;
+
+	git_global_config(&user, &xdg);
+	if (xdg && *xdg) {
+		normalize_path_copy(xdg, xdg);
+		strbuf_addf(&buf, "%s\n", xdg);
+	}
+	if (user && *user) {
+		normalize_path_copy(user, user);
+		strbuf_addf(&buf, "%s\n", user);
+	}
+	free(xdg);
+	free(user);
+	strbuf_trim_trailing_newline(&buf);
+	if (buf.len == 0) {
+		strbuf_release(&buf);
+		return NULL;
+	}
+	return strbuf_detach(&buf, &unused);
 }
 
 struct git_var {
 	const char *name;
-	const char *(*read)(int);
+	char *(*read)(int);
+	int multivalued;
 };
 static struct git_var git_vars[] = {
-	{ "GIT_COMMITTER_IDENT", git_committer_info },
-	{ "GIT_AUTHOR_IDENT",   git_author_info },
-	{ "GIT_EDITOR", editor },
-	{ "GIT_SEQUENCE_EDITOR", sequence_editor },
-	{ "GIT_PAGER", pager },
-	{ "GIT_DEFAULT_BRANCH", default_branch },
-	{ "", NULL },
+	{
+		.name = "GIT_COMMITTER_IDENT",
+		.read = committer,
+	},
+	{
+		.name = "GIT_AUTHOR_IDENT",
+		.read = author,
+	},
+	{
+		.name = "GIT_EDITOR",
+		.read = editor,
+	},
+	{
+		.name = "GIT_SEQUENCE_EDITOR",
+		.read = sequence_editor,
+	},
+	{
+		.name = "GIT_PAGER",
+		.read = pager,
+	},
+	{
+		.name = "GIT_DEFAULT_BRANCH",
+		.read = default_branch,
+	},
+	{
+		.name = "GIT_SHELL_PATH",
+		.read = shell_path,
+	},
+	{
+		.name = "GIT_ATTR_SYSTEM",
+		.read = git_attr_val_system,
+	},
+	{
+		.name = "GIT_ATTR_GLOBAL",
+		.read = git_attr_val_global,
+	},
+	{
+		.name = "GIT_CONFIG_SYSTEM",
+		.read = git_config_val_system,
+	},
+	{
+		.name = "GIT_CONFIG_GLOBAL",
+		.read = git_config_val_global,
+		.multivalued = 1,
+	},
+	{
+		.name = "",
+		.read = NULL,
+	},
 };
 
 static void list_vars(void)
 {
 	struct git_var *ptr;
-	const char *val;
+	char *val;
 
 	for (ptr = git_vars; ptr->read; ptr++)
-		if ((val = ptr->read(0)))
-			printf("%s=%s\n", ptr->name, val);
+		if ((val = ptr->read(0))) {
+			if (ptr->multivalued && *val) {
+				struct string_list list = STRING_LIST_INIT_DUP;
+				int i;
+
+				string_list_split(&list, val, '\n', -1);
+				for (i = 0; i < list.nr; i++)
+					printf("%s=%s\n", ptr->name, list.items[i].string);
+				string_list_clear(&list, 0);
+			} else {
+				printf("%s=%s\n", ptr->name, val);
+			}
+			free(val);
+		}
 }
 
 static const struct git_var *get_git_var(const char *var)
@@ -83,7 +211,7 @@ static int show_config(const char *var, const char *value, void *cb)
 int cmd_var(int argc, const char **argv, const char *prefix UNUSED)
 {
 	const struct git_var *git_var;
-	const char *val;
+	char *val;
 
 	if (argc != 2)
 		usage(var_usage);
@@ -104,6 +232,7 @@ int cmd_var(int argc, const char **argv, const char *prefix UNUSED)
 		return 1;
 
 	printf("%s\n", val);
+	free(val);
 
 	return 0;
 }