1 files changed, 500 insertions, 0 deletions
diff --git a/builtin/help.c b/builtin/help.c
new file mode 100644
index 0000000000..3c55ce4563
--- /dev/null
+++ b/builtin/help.c
@@ -0,0 +1,500 @@
+/*
+ * Builtin help command
+ */
+#include "cache.h"
+#include "builtin.h"
+#include "exec_cmd.h"
+#include "parse-options.h"
+#include "run-command.h"
+#include "column.h"
+#include "help.h"
+
+#ifndef DEFAULT_HELP_FORMAT
+#define DEFAULT_HELP_FORMAT "man"
+#endif
+
+static struct man_viewer_list {
+	struct man_viewer_list *next;
+	char name[FLEX_ARRAY];
+} *man_viewer_list;
+
+static struct man_viewer_info_list {
+	struct man_viewer_info_list *next;
+	const char *info;
+	char name[FLEX_ARRAY];
+} *man_viewer_info_list;
+
+enum help_format {
+	HELP_FORMAT_NONE,
+	HELP_FORMAT_MAN,
+	HELP_FORMAT_INFO,
+	HELP_FORMAT_WEB
+};
+
+static const char *html_path;
+
+static int show_all = 0;
+static int show_guides = 0;
+static unsigned int colopts;
+static enum help_format help_format = HELP_FORMAT_NONE;
+static struct option builtin_help_options[] = {
+	OPT_BOOL('a', "all", &show_all, N_("print all available commands")),
+	OPT_BOOL('g', "guides", &show_guides, N_("print list of useful guides")),
+	OPT_SET_INT('m', "man", &help_format, N_("show man page"), HELP_FORMAT_MAN),
+	OPT_SET_INT('w', "web", &help_format, N_("show manual in web browser"),
+			HELP_FORMAT_WEB),
+	OPT_SET_INT('i', "info", &help_format, N_("show info page"),
+			HELP_FORMAT_INFO),
+	OPT_END(),
+};
+
+static const char * const builtin_help_usage[] = {
+	N_("git help [--all] [--guides] [--man | --web | --info] [<command>]"),
+	NULL
+};
+
+static enum help_format parse_help_format(const char *format)
+{
+	if (!strcmp(format, "man"))
+		return HELP_FORMAT_MAN;
+	if (!strcmp(format, "info"))
+		return HELP_FORMAT_INFO;
+	if (!strcmp(format, "web") || !strcmp(format, "html"))
+		return HELP_FORMAT_WEB;
+	die(_("unrecognized help format '%s'"), format);
+}
+
+static const char *get_man_viewer_info(const char *name)
+{
+	struct man_viewer_info_list *viewer;
+
+	for (viewer = man_viewer_info_list; viewer; viewer = viewer->next)
+	{
+		if (!strcasecmp(name, viewer->name))
+			return viewer->info;
+	}
+	return NULL;
+}
+
+static int check_emacsclient_version(void)
+{
+	struct strbuf buffer = STRBUF_INIT;
+	struct child_process ec_process = CHILD_PROCESS_INIT;
+	const char *argv_ec[] = { "emacsclient", "--version", NULL };
+	int version;
+
+	/* emacsclient prints its version number on stderr */
+	ec_process.argv = argv_ec;
+	ec_process.err = -1;
+	ec_process.stdout_to_stderr = 1;
+	if (start_command(&ec_process))
+		return error(_("Failed to start emacsclient."));
+
+	strbuf_read(&buffer, ec_process.err, 20);
+	close(ec_process.err);
+
+	/*
+	 * Don't bother checking return value, because "emacsclient --version"
+	 * seems to always exits with code 1.
+	 */
+	finish_command(&ec_process);
+
+	if (!starts_with(buffer.buf, "emacsclient")) {
+		strbuf_release(&buffer);
+		return error(_("Failed to parse emacsclient version."));
+	}
+
+	strbuf_remove(&buffer, 0, strlen("emacsclient"));
+	version = atoi(buffer.buf);
+
+	if (version < 22) {
+		strbuf_release(&buffer);
+		return error(_("emacsclient version '%d' too old (< 22)."),
+			version);
+	}
+
+	strbuf_release(&buffer);
+	return 0;
+}
+
+static void exec_woman_emacs(const char *path, const char *page)
+{
+	if (!check_emacsclient_version()) {
+		/* This works only with emacsclient version >= 22. */
+		struct strbuf man_page = STRBUF_INIT;
+
+		if (!path)
+			path = "emacsclient";
+		strbuf_addf(&man_page, "(woman \"%s\")", page);
+		execlp(path, "emacsclient", "-e", man_page.buf, (char *)NULL);
+		warning(_("failed to exec '%s': %s"), path, strerror(errno));
+	}
+}
+
+static void exec_man_konqueror(const char *path, const char *page)
+{
+	const char *display = getenv("DISPLAY");
+	if (display && *display) {
+		struct strbuf man_page = STRBUF_INIT;
+		const char *filename = "kfmclient";
+
+		/* It's simpler to launch konqueror using kfmclient. */
+		if (path) {
+			size_t len;
+			if (strip_suffix(path, "/konqueror", &len))
+				path = xstrfmt("%.*s/kfmclient", (int)len, path);
+			filename = basename((char *)path);
+		} else
+			path = "kfmclient";
+		strbuf_addf(&man_page, "man:%s(1)", page);
+		execlp(path, filename, "newTab", man_page.buf, (char *)NULL);
+		warning(_("failed to exec '%s': %s"), path, strerror(errno));
+	}
+}
+
+static void exec_man_man(const char *path, const char *page)
+{
+	if (!path)
+		path = "man";
+	execlp(path, "man", page, (char *)NULL);
+	warning(_("failed to exec '%s': %s"), path, strerror(errno));
+}
+
+static void exec_man_cmd(const char *cmd, const char *page)
+{
+	struct strbuf shell_cmd = STRBUF_INIT;
+	strbuf_addf(&shell_cmd, "%s %s", cmd, page);
+	execl(SHELL_PATH, SHELL_PATH, "-c", shell_cmd.buf, (char *)NULL);
+	warning(_("failed to exec '%s': %s"), cmd, strerror(errno));
+}
+
+static void add_man_viewer(const char *name)
+{
+	struct man_viewer_list **p = &man_viewer_list;
+
+	while (*p)
+		p = &((*p)->next);
+	FLEX_ALLOC_STR(*p, name, name);
+}
+
+static int supported_man_viewer(const char *name, size_t len)
+{
+	return (!strncasecmp("man", name, len) ||
+		!strncasecmp("woman", name, len) ||
+		!strncasecmp("konqueror", name, len));
+}
+
+static void do_add_man_viewer_info(const char *name,
+				   size_t len,
+				   const char *value)
+{
+	struct man_viewer_info_list *new;
+	FLEX_ALLOC_MEM(new, name, name, len);
+	new->info = xstrdup(value);
+	new->next = man_viewer_info_list;
+	man_viewer_info_list = new;
+}
+
+static int add_man_viewer_path(const char *name,
+			       size_t len,
+			       const char *value)
+{
+	if (supported_man_viewer(name, len))
+		do_add_man_viewer_info(name, len, value);
+	else
+		warning(_("'%s': path for unsupported man viewer.\n"
+			  "Please consider using 'man.<tool>.cmd' instead."),
+			name);
+
+	return 0;
+}
+
+static int add_man_viewer_cmd(const char *name,
+			      size_t len,
+			      const char *value)
+{
+	if (supported_man_viewer(name, len))
+		warning(_("'%s': cmd for supported man viewer.\n"
+			  "Please consider using 'man.<tool>.path' instead."),
+			name);
+	else
+		do_add_man_viewer_info(name, len, value);
+
+	return 0;
+}
+
+static int add_man_viewer_info(const char *var, const char *value)
+{
+	const char *name, *subkey;
+	int namelen;
+
+	if (parse_config_key(var, "man", &name, &namelen, &subkey) < 0 || !name)
+		return 0;
+
+	if (!strcmp(subkey, "path")) {
+		if (!value)
+			return config_error_nonbool(var);
+		return add_man_viewer_path(name, namelen, value);
+	}
+	if (!strcmp(subkey, "cmd")) {
+		if (!value)
+			return config_error_nonbool(var);
+		return add_man_viewer_cmd(name, namelen, value);
+	}
+
+	return 0;
+}
+
+static int git_help_config(const char *var, const char *value, void *cb)
+{
+	if (starts_with(var, "column."))
+		return git_column_config(var, value, "help", &colopts);
+	if (!strcmp(var, "help.format")) {
+		if (!value)
+			return config_error_nonbool(var);
+		help_format = parse_help_format(value);
+		return 0;
+	}
+	if (!strcmp(var, "help.htmlpath")) {
+		if (!value)
+			return config_error_nonbool(var);
+		html_path = xstrdup(value);
+		return 0;
+	}
+	if (!strcmp(var, "man.viewer")) {
+		if (!value)
+			return config_error_nonbool(var);
+		add_man_viewer(value);
+		return 0;
+	}
+	if (starts_with(var, "man."))
+		return add_man_viewer_info(var, value);
+
+	return git_default_config(var, value, cb);
+}
+
+static struct cmdnames main_cmds, other_cmds;
+
+static int is_git_command(const char *s)
+{
+	if (is_builtin(s))
+		return 1;
+
+	load_command_list("git-", &main_cmds, &other_cmds);
+	return is_in_cmdlist(&main_cmds, s) ||
+		is_in_cmdlist(&other_cmds, s);
+}
+
+static const char *cmd_to_page(const char *git_cmd)
+{
+	if (!git_cmd)
+		return "git";
+	else if (starts_with(git_cmd, "git"))
+		return git_cmd;
+	else if (is_git_command(git_cmd))
+		return xstrfmt("git-%s", git_cmd);
+	else
+		return xstrfmt("git%s", git_cmd);
+}
+
+static void setup_man_path(void)
+{
+	struct strbuf new_path = STRBUF_INIT;
+	const char *old_path = getenv("MANPATH");
+	char *git_man_path = system_path(GIT_MAN_PATH);
+
+	/* We should always put ':' after our path. If there is no
+	 * old_path, the ':' at the end will let 'man' to try
+	 * system-wide paths after ours to find the manual page. If
+	 * there is old_path, we need ':' as delimiter. */
+	strbuf_addstr(&new_path, git_man_path);
+	strbuf_addch(&new_path, ':');
+	if (old_path)
+		strbuf_addstr(&new_path, old_path);
+
+	free(git_man_path);
+	setenv("MANPATH", new_path.buf, 1);
+
+	strbuf_release(&new_path);
+}
+
+static void exec_viewer(const char *name, const char *page)
+{
+	const char *info = get_man_viewer_info(name);
+
+	if (!strcasecmp(name, "man"))
+		exec_man_man(info, page);
+	else if (!strcasecmp(name, "woman"))
+		exec_woman_emacs(info, page);
+	else if (!strcasecmp(name, "konqueror"))
+		exec_man_konqueror(info, page);
+	else if (info)
+		exec_man_cmd(info, page);
+	else
+		warning(_("'%s': unknown man viewer."), name);
+}
+
+static void show_man_page(const char *git_cmd)
+{
+	struct man_viewer_list *viewer;
+	const char *page = cmd_to_page(git_cmd);
+	const char *fallback = getenv("GIT_MAN_VIEWER");
+
+	setup_man_path();
+	for (viewer = man_viewer_list; viewer; viewer = viewer->next)
+	{
+		exec_viewer(viewer->name, page); /* will return when unable */
+	}
+	if (fallback)
+		exec_viewer(fallback, page);
+	exec_viewer("man", page);
+	die(_("no man viewer handled the request"));
+}
+
+static void show_info_page(const char *git_cmd)
+{
+	const char *page = cmd_to_page(git_cmd);
+	setenv("INFOPATH", system_path(GIT_INFO_PATH), 1);
+	execlp("info", "info", "gitman", page, (char *)NULL);
+	die(_("no info viewer handled the request"));
+}
+
+static void get_html_page_path(struct strbuf *page_path, const char *page)
+{
+	struct stat st;
+	char *to_free = NULL;
+
+	if (!html_path)
+		html_path = to_free = system_path(GIT_HTML_PATH);
+
+	/* Check that we have a git documentation directory. */
+	if (!strstr(html_path, "://")) {
+		if (stat(mkpath("%s/git.html", html_path), &st)
+		    || !S_ISREG(st.st_mode))
+			die("'%s': not a documentation directory.", html_path);
+	}
+
+	strbuf_init(page_path, 0);
+	strbuf_addf(page_path, "%s/%s.html", html_path, page);
+	free(to_free);
+}
+
+/*
+ * If open_html is not defined in a platform-specific way (see for
+ * example compat/mingw.h), we use the script web--browse to display
+ * HTML.
+ */
+#ifndef open_html
+static void open_html(const char *path)
+{
+	execl_git_cmd("web--browse", "-c", "help.browser", path, (char *)NULL);
+}
+#endif
+
+static void show_html_page(const char *git_cmd)
+{
+	const char *page = cmd_to_page(git_cmd);
+	struct strbuf page_path; /* it leaks but we exec bellow */
+
+	get_html_page_path(&page_path, page);
+
+	open_html(page_path.buf);
+}
+
+static struct {
+	const char *name;
+	const char *help;
+} common_guides[] = {
+	{ "attributes", N_("Defining attributes per path") },
+	{ "everyday", N_("Everyday Git With 20 Commands Or So") },
+	{ "glossary", N_("A Git glossary") },
+	{ "ignore", N_("Specifies intentionally untracked files to ignore") },
+	{ "modules", N_("Defining submodule properties") },
+	{ "revisions", N_("Specifying revisions and ranges for Git") },
+	{ "tutorial", N_("A tutorial introduction to Git (for version 1.5.1 or newer)") },
+	{ "workflows", N_("An overview of recommended workflows with Git") },
+};
+
+static void list_common_guides_help(void)
+{
+	int i, longest = 0;
+
+	for (i = 0; i < ARRAY_SIZE(common_guides); i++) {
+		if (longest < strlen(common_guides[i].name))
+			longest = strlen(common_guides[i].name);
+	}
+
+	puts(_("The common Git guides are:\n"));
+	for (i = 0; i < ARRAY_SIZE(common_guides); i++) {
+		printf("   %s   ", common_guides[i].name);
+		mput_char(' ', longest - strlen(common_guides[i].name));
+		puts(_(common_guides[i].help));
+	}
+	putchar('\n');
+}
+
+int cmd_help(int argc, const char **argv, const char *prefix)
+{
+	int nongit;
+	char *alias;
+	enum help_format parsed_help_format;
+
+	argc = parse_options(argc, argv, prefix, builtin_help_options,
+			builtin_help_usage, 0);
+	parsed_help_format = help_format;
+
+	if (show_all) {
+		git_config(git_help_config, NULL);
+		printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
+		load_command_list("git-", &main_cmds, &other_cmds);
+		list_commands(colopts, &main_cmds, &other_cmds);
+	}
+
+	if (show_guides)
+		list_common_guides_help();
+
+	if (show_all || show_guides) {
+		printf("%s\n", _(git_more_info_string));
+		/*
+		* We're done. Ignore any remaining args
+		*/
+		return 0;
+	}
+
+	if (!argv[0]) {
+		printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
+		list_common_cmds_help();
+		printf("\n%s\n", _(git_more_info_string));
+		return 0;
+	}
+
+	setup_git_directory_gently(&nongit);
+	git_config(git_help_config, NULL);
+
+	if (parsed_help_format != HELP_FORMAT_NONE)
+		help_format = parsed_help_format;
+	if (help_format == HELP_FORMAT_NONE)
+		help_format = parse_help_format(DEFAULT_HELP_FORMAT);
+
+	alias = alias_lookup(argv[0]);
+	if (alias && !is_git_command(argv[0])) {
+		printf_ln(_("`git %s' is aliased to `%s'"), argv[0], alias);
+		free(alias);
+		return 0;
+	}
+
+	switch (help_format) {
+	case HELP_FORMAT_NONE:
+	case HELP_FORMAT_MAN:
+		show_man_page(argv[0]);
+		break;
+	case HELP_FORMAT_INFO:
+		show_info_page(argv[0]);
+		break;
+	case HELP_FORMAT_WEB:
+		show_html_page(argv[0]);
+		break;
+	}
+
+	return 0;
+}