cli: accept configuration on the command line

Introduce `cli_repository_open` which will reparse command-line options
looking for `-c` or `--config-env`. Add those values to an in-memory
configuration database and configure the opened repository with that.

src/cli/cli.h

-/*
- * Copyright (C) the libgit2 contributors. All rights reserved.
- *
- * This file is part of libgit2, distributed under the GNU GPL v2 with
- * a Linking Exception. For full terms see the included COPYING file.
- */
-
-#ifndef CLI_cli_h__
-#define CLI_cli_h__
-
-#define PROGRAM_NAME "git2"
-
-#include "git2_util.h"
-
-#include "error.h"
-#include "opt.h"
-#include "opt_usage.h"
-#include "sighandler.h"
-
-#endif /* CLI_cli_h__ */

src/cli/cmd.c

@@ -5,7 +5,7 @@
  * a Linking Exception. For full terms see the included COPYING file.
  */
 
-#include "cli.h"
+#include "common.h"
 #include "cmd.h"
 
 const cli_cmd_spec *cli_cmd_spec_byname(const char *name)

src/cli/cmd_cat_file.c

@@ -6,7 +6,7 @@
  */
 
 #include <git2.h>
-#include "cli.h"
+#include "common.h"
 #include "cmd.h"
 
 #define COMMAND_NAME "cat-file"

src/cli/cmd_clone.c

@@ -7,7 +7,7 @@
 
 #include <stdio.h>
 #include <git2.h>
-#include "cli.h"
+#include "common.h"
 #include "cmd.h"
 #include "error.h"
 #include "sighandler.h"

src/cli/cmd_config.c

@@ -6,7 +6,8 @@
  */
 
 #include <git2.h>
-#include "cli.h"
+
+#include "common.h"
 #include "cmd.h"
 
 #define COMMAND_NAME "config"
@@ -24,10 +25,20 @@ static int show_help;
 static int null_separator;
 static char *name;
 
+#define CLI_COMMON_OPT_HELP \
+	CLI_OPT_TYPE_SWITCH, "help",       0, &show_help, 1, \
+	CLI_OPT_USAGE_HIDDEN | CLI_OPT_USAGE_STOP_PARSING
+#define CLI_COMMON_OPT_CONFIG \
+	CLI_OPT_TYPE_VALUE,   NULL,       'c', NULL,      0, \
+	CLI_OPT_USAGE_HIDDEN
+#define CLI_COMMON_OPT_CONFIG_ENV \
+	CLI_OPT_TYPE_VALUE,  "config-env", 0,  NULL,      0, \
+	CLI_OPT_USAGE_HIDDEN
+
 static const cli_opt_spec opts[] = {
-	{ CLI_OPT_TYPE_SWITCH,    "help",    0, &show_help,   1,
-	  CLI_OPT_USAGE_HIDDEN | CLI_OPT_USAGE_STOP_PARSING, NULL,
-	  "display help about the " COMMAND_NAME " command" },
+	{ CLI_COMMON_OPT_HELP },
+	{ CLI_COMMON_OPT_CONFIG },
+	{ CLI_COMMON_OPT_CONFIG_ENV },
 
 	{ CLI_OPT_TYPE_SWITCH,    "null",       'z', &null_separator, 1,
 	  0,                       NULL,        "use NUL as a separator" },
@@ -137,6 +148,7 @@ int cmd_config(int argc, char **argv)
 {
 	git_repository *repo = NULL;
 	git_config *config = NULL;
+	cli_repository_open_options open_opts = { argv + 1, argc - 1};
 	cli_opt invalid_opt;
 	int ret = 0;
 
@@ -148,7 +160,7 @@ int cmd_config(int argc, char **argv)
 		return 0;
 	}
 
-	if (git_repository_open_ext(&repo, ".", GIT_REPOSITORY_OPEN_FROM_ENV, NULL) < 0 ||
+	if (cli_repository_open(&repo, &open_opts) < 0 ||
 	    git_repository_config(&config, repo) < 0) {
 		ret = cli_error_git();
 		goto done;

src/cli/cmd_hash_object.c

@@ -6,7 +6,7 @@
  */
 
 #include <git2.h>
-#include "cli.h"
+#include "common.h"
 #include "cmd.h"
 
 #include "futils.h"

src/cli/cmd_help.c

@@ -7,7 +7,7 @@
 
 #include <stdio.h>
 #include <git2.h>
-#include "cli.h"
+#include "common.h"
 #include "cmd.h"
 
 #define COMMAND_NAME "help"

src/cli/common.c

+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#include <git2.h>
+#include <git2/sys/config.h>
+
+#include "git2_util.h"
+#include "vector.h"
+
+#include "common.h"
+#include "error.h"
+
+static int parse_option(cli_opt *opt, void *data)
+{
+	git_str kv = GIT_STR_INIT, env = GIT_STR_INIT;
+	git_vector *cmdline_config = data;
+	int error = 0;
+
+	if (opt->spec && opt->spec->alias == 'c') {
+		if (git_str_puts(&kv, opt->value) < 0) {
+			error = cli_error_git();
+			goto done;
+		}
+	}
+
+	else if (opt->spec && !strcmp(opt->spec->name, "config-env")) {
+		char *val = strchr(opt->value, '=');
+
+		if (val == NULL || *(val + 1) == '\0') {
+			error = cli_error("invalid config format: '%s'", opt->value);
+			goto done;
+		}
+
+		if (git_str_put(&kv, opt->value, (val - opt->value)) < 0) {
+			error = cli_error_git();
+			goto done;
+		}
+
+		val++;
+
+		if ((error = git__getenv(&env, val)) == GIT_ENOTFOUND) {
+			error = cli_error("missing environment variable '%s' for configuration '%s'", val, kv.ptr);
+			goto done;
+		} else if (error) {
+			error = cli_error_git();
+			goto done;
+		}
+
+		if (git_str_putc(&kv, '=') < 0 ||
+		    git_str_puts(&kv, env.ptr) < 0) {
+			error = cli_error_git();
+			goto done;
+		}
+	}
+
+	if (kv.size > 0 &&
+	    git_vector_insert(cmdline_config, git_str_detach(&kv)) < 0)
+		error = cli_error_git();
+
+done:
+	git_str_dispose(&env);
+	git_str_dispose(&kv);
+	return error;
+}
+
+static int parse_common_options(
+	git_repository *repo,
+	cli_repository_open_options *opts)
+{
+	cli_opt_spec common_opts[] = {
+		{ CLI_COMMON_OPT_CONFIG },
+		{ CLI_COMMON_OPT_CONFIG_ENV },
+		{ 0 }
+	};
+	git_config_backend_memory_options config_opts =
+		GIT_CONFIG_BACKEND_MEMORY_OPTIONS_INIT;
+	git_vector cmdline = GIT_VECTOR_INIT;
+	git_config *config = NULL;
+	git_config_backend *backend = NULL;
+	int error = 0;
+
+	config_opts.backend_type = "command line";
+
+	if ((error = cli_opt_foreach(common_opts, opts->args,
+			opts->args_len, CLI_OPT_PARSE_GNU, parse_option,
+			&cmdline)) < 0)
+		goto done;
+
+	if (git_vector_length(&cmdline) == 0)
+		goto done;
+
+	if (git_repository_config(&config, repo) < 0 ||
+	    git_config_backend_from_values(&backend,
+			(const char **)cmdline.contents, cmdline.length,
+			&config_opts) < 0 ||
+	    git_config_add_backend(config, backend, GIT_CONFIG_LEVEL_APP,
+			repo, 0) < 0)
+		error = cli_error_git();
+
+done:
+	if (error && backend)
+		backend->free(backend);
+	git_config_free(config);
+	git_vector_free_deep(&cmdline);
+	return error;
+}
+
+int cli_repository_open(
+	git_repository **out,
+	cli_repository_open_options *opts)
+{
+	git_repository *repo;
+
+	if (git_repository_open_ext(&repo, ".", GIT_REPOSITORY_OPEN_FROM_ENV, NULL) < 0)
+		return -1;
+
+	if (opts && parse_common_options(repo, opts) < 0)
+		return -1;
+
+	*out = repo;
+	return 0;
+}

src/cli/common.h

+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#ifndef CLI_common_h__
+#define CLI_common_h__
+
+#define PROGRAM_NAME "git2"
+
+#include "git2_util.h"
+
+#include "error.h"
+#include "opt.h"
+#include "opt_usage.h"
+
+/*
+ * Common command arguments.
+ */
+
+#define CLI_COMMON_OPT_HELP \
+	CLI_OPT_TYPE_SWITCH, "help",       0, &show_help, 1, \
+	CLI_OPT_USAGE_HIDDEN | CLI_OPT_USAGE_STOP_PARSING
+#define CLI_COMMON_OPT_CONFIG \
+	CLI_OPT_TYPE_VALUE,   NULL,       'c', NULL,      0, \
+	CLI_OPT_USAGE_HIDDEN
+#define CLI_COMMON_OPT_CONFIG_ENV \
+	CLI_OPT_TYPE_VALUE,  "config-env", 0,  NULL,      0, \
+	CLI_OPT_USAGE_HIDDEN
+
+#define CLI_COMMON_OPT \
+	{ CLI_COMMON_OPT_HELP }, \
+	{ CLI_COMMON_OPT_CONFIG }, \
+	{ CLI_COMMON_OPT_CONFIG_ENV }
+
+typedef struct {
+	char **args;
+	int args_len;
+} cli_repository_open_options;
+
+extern int cli_repository_open(
+	git_repository **out,
+	cli_repository_open_options *opts);
+
+#endif /* CLI_common_h__ */

src/cli/error.h

@@ -8,7 +8,7 @@
 #ifndef CLI_error_h__
 #define CLI_error_h__
 
-#include "cli.h"
+#include "common.h"
 #include <stdio.h>
 
 #define CLI_EXIT_OK      0

src/cli/main.c

@@ -7,7 +7,7 @@
 
 #include <stdio.h>
 #include <git2.h>
-#include "cli.h"
+#include "common.h"
 #include "cmd.h"
 
 static int show_help = 0;

src/cli/opt.c

@@ -19,7 +19,7 @@
 #include <limits.h>
 #include <assert.h>
 
-#include "cli.h"
+#include "common.h"
 #include "opt.h"
 
 #ifdef _WIN32
@@ -73,7 +73,7 @@ GIT_INLINE(const cli_opt_spec *) spec_for_long(
 
 		/* Handle --option=value arguments */
 		if (spec->type == CLI_OPT_TYPE_VALUE &&
-		    eql &&
+		    spec->name && eql &&
 		    strncmp(arg, spec->name, eql_pos) == 0 &&
 		    spec->name[eql_pos] == '\0') {
 			*has_value = 1;
@@ -575,6 +575,28 @@ cli_opt_status_t cli_opt_parse(
 	return validate_required(opt, specs, given_specs);
 }
 
+int cli_opt_foreach(
+	const cli_opt_spec specs[],
+	char **args,
+	size_t args_len,
+	unsigned int flags,
+	int (*callback)(cli_opt *, void *),
+	void *callback_data)
+{
+	cli_opt_parser parser;
+	cli_opt opt;
+	int ret;
+
+	cli_opt_parser_init(&parser, specs, args, args_len, flags);
+
+	while (cli_opt_parser_next(&opt, &parser)) {
+		if ((ret = callback(&opt, callback_data)) != 0)
+			return ret;
+	}
+
+	return 0;
+}
+
 static int spec_name_fprint(FILE *file, const cli_opt_spec *spec)
 {
 	int error;

src/cli/opt.h

@@ -300,6 +300,14 @@ cli_opt_status_t cli_opt_parse(
     size_t args_len,
     unsigned int flags);
 
+int cli_opt_foreach(
+	const cli_opt_spec specs[],
+	char **args,
+	size_t args_len,
+	unsigned int flags,
+	int (*callback)(cli_opt *, void *),
+	void *callback_data);
+
 /**
  * Initializes a parser that parses the given arguments according to the
  * given specifications.

src/cli/opt_usage.c

@@ -5,7 +5,7 @@
  * a Linking Exception. For full terms see the included COPYING file.
  */
 
-#include "cli.h"
+#include "common.h"
 #include "str.h"
 
 static int print_spec_name(git_str *out, const cli_opt_spec *spec)

src/cli/unix/sighandler.c

@@ -8,7 +8,8 @@
 #include <stdint.h>
 #include <signal.h>
 #include "git2_util.h"
-#include "cli.h"
+#include "common.h"
+#include "sighandler.h"
 
 static void (*interrupt_handler)(void) = NULL;
 

src/cli/win32/precompiled.h

 #include <git2.h>
 
-#include "cli.h"
+#include "common.h"

src/cli/win32/sighandler.c

@@ -8,7 +8,7 @@
 #include "git2_util.h"
 #include <windows.h>
 
-#include "cli.h"
+#include "sighandler.h"
 
 static void (*interrupt_handler)(void) = NULL;