builtins: Makefile clean-up

This cleans up the build procedure for built-in commands by:

 - generating mostly redundant definition of BUILT_INS from
   BUILTIN_OBJS in the Makefile,
 - renaming a few files to make the above possible, and
 - sorting the built-in command table in git.c.

It might be a good idea to binary search (or perfect hash) the built-in
command table, but that can be done later when somebody feels like.

Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 234 insertions, 0 deletions

diff --git a/help.c b/help.c
new file mode 100644
index 0000000000..fb731cc934
--- /dev/null
+++ b/help.c
@@ -0,0 +1,234 @@
+/*
+ * builtin-help.c
+ *
+ * Builtin help-related commands (help, usage, version)
+ */
+#include <sys/ioctl.h>
+#include "cache.h"
+#include "builtin.h"
+#include "exec_cmd.h"
+#include "common-cmds.h"
+
+
+/* most GUI terminals set COLUMNS (although some don't export it) */
+static int term_columns(void)
+{
+	char *col_string = getenv("COLUMNS");
+	int n_cols = 0;
+
+	if (col_string && (n_cols = atoi(col_string)) > 0)
+		return n_cols;
+
+#ifdef TIOCGWINSZ
+	{
+		struct winsize ws;
+		if (!ioctl(1, TIOCGWINSZ, &ws)) {
+			if (ws.ws_col)
+				return ws.ws_col;
+		}
+	}
+#endif
+
+	return 80;
+}
+
+static void oom(void)
+{
+	fprintf(stderr, "git: out of memory\n");
+	exit(1);
+}
+
+static inline void mput_char(char c, unsigned int num)
+{
+	while(num--)
+		putchar(c);
+}
+
+static struct cmdname {
+	size_t len;
+	char name[1];
+} **cmdname;
+static int cmdname_alloc, cmdname_cnt;
+
+static void add_cmdname(const char *name, int len)
+{
+	struct cmdname *ent;
+	if (cmdname_alloc <= cmdname_cnt) {
+		cmdname_alloc = cmdname_alloc + 200;
+		cmdname = realloc(cmdname, cmdname_alloc * sizeof(*cmdname));
+		if (!cmdname)
+			oom();
+	}
+	ent = malloc(sizeof(*ent) + len);
+	if (!ent)
+		oom();
+	ent->len = len;
+	memcpy(ent->name, name, len);
+	ent->name[len] = 0;
+	cmdname[cmdname_cnt++] = ent;
+}
+
+static int cmdname_compare(const void *a_, const void *b_)
+{
+	struct cmdname *a = *(struct cmdname **)a_;
+	struct cmdname *b = *(struct cmdname **)b_;
+	return strcmp(a->name, b->name);
+}
+
+static void pretty_print_string_list(struct cmdname **cmdname, int longest)
+{
+	int cols = 1, rows;
+	int space = longest + 1; /* min 1 SP between words */
+	int max_cols = term_columns() - 1; /* don't print *on* the edge */
+	int i, j;
+
+	if (space < max_cols)
+		cols = max_cols / space;
+	rows = (cmdname_cnt + cols - 1) / cols;
+
+	qsort(cmdname, cmdname_cnt, sizeof(*cmdname), cmdname_compare);
+
+	for (i = 0; i < rows; i++) {
+		printf("  ");
+
+		for (j = 0; j < cols; j++) {
+			int n = j * rows + i;
+			int size = space;
+			if (n >= cmdname_cnt)
+				break;
+			if (j == cols-1 || n + rows >= cmdname_cnt)
+				size = 1;
+			printf("%-*s", size, cmdname[n]->name);
+		}
+		putchar('\n');
+	}
+}
+
+static void list_commands(const char *exec_path, const char *pattern)
+{
+	unsigned int longest = 0;
+	char path[PATH_MAX];
+	int dirlen;
+	DIR *dir = opendir(exec_path);
+	struct dirent *de;
+
+	if (!dir) {
+		fprintf(stderr, "git: '%s': %s\n", exec_path, strerror(errno));
+		exit(1);
+	}
+
+	dirlen = strlen(exec_path);
+	if (PATH_MAX - 20 < dirlen) {
+		fprintf(stderr, "git: insanely long exec-path '%s'\n",
+			exec_path);
+		exit(1);
+	}
+
+	memcpy(path, exec_path, dirlen);
+	path[dirlen++] = '/';
+
+	while ((de = readdir(dir)) != NULL) {
+		struct stat st;
+		int entlen;
+
+		if (strncmp(de->d_name, "git-", 4))
+			continue;
+		strcpy(path+dirlen, de->d_name);
+		if (stat(path, &st) || /* stat, not lstat */
+		    !S_ISREG(st.st_mode) ||
+		    !(st.st_mode & S_IXUSR))
+			continue;
+
+		entlen = strlen(de->d_name);
+		if (4 < entlen && !strcmp(de->d_name + entlen - 4, ".exe"))
+			entlen -= 4;
+
+		if (longest < entlen)
+			longest = entlen;
+
+		add_cmdname(de->d_name + 4, entlen-4);
+	}
+	closedir(dir);
+
+	printf("git commands available in '%s'\n", exec_path);
+	printf("----------------------------");
+	mput_char('-', strlen(exec_path));
+	putchar('\n');
+	pretty_print_string_list(cmdname, longest - 4);
+	putchar('\n');
+}
+
+static void list_common_cmds_help(void)
+{
+	int i, longest = 0;
+
+	for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
+		if (longest < strlen(common_cmds[i].name))
+			longest = strlen(common_cmds[i].name);
+	}
+
+	puts("The most commonly used git commands are:");
+	for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
+		printf("    %s", common_cmds[i].name);
+		mput_char(' ', longest - strlen(common_cmds[i].name) + 4);
+		puts(common_cmds[i].help);
+	}
+	puts("(use 'git help -a' to get a list of all installed git commands)");
+}
+
+static void show_man_page(const char *git_cmd)
+{
+	const char *page;
+
+	if (!strncmp(git_cmd, "git", 3))
+		page = git_cmd;
+	else {
+		int page_len = strlen(git_cmd) + 4;
+		char *p = malloc(page_len + 1);
+		strcpy(p, "git-");
+		strcpy(p + 4, git_cmd);
+		p[page_len] = 0;
+		page = p;
+	}
+
+	execlp("man", "man", page, NULL);
+}
+
+void help_unknown_cmd(const char *cmd)
+{
+	printf("git: '%s' is not a git-command\n\n", cmd);
+	list_common_cmds_help();
+	exit(1);
+}
+
+int cmd_version(int argc, const char **argv, const char *prefix)
+{
+	printf("git version %s\n", git_version_string);
+	return 0;
+}
+
+int cmd_help(int argc, const char **argv, const char *prefix)
+{
+	const char *help_cmd = argc > 1 ? argv[1] : NULL;
+	const char *exec_path = git_exec_path();
+
+	if (!help_cmd) {
+		printf("usage: %s\n\n", git_usage_string);
+		list_common_cmds_help();
+		exit(1);
+	}
+
+	else if (!strcmp(help_cmd, "--all") || !strcmp(help_cmd, "-a")) {
+		printf("usage: %s\n\n", git_usage_string);
+		if(exec_path)
+			list_commands(exec_path, "git-*");
+		exit(1);
+	}
+
+	else
+		show_man_page(help_cmd);
+
+	return 0;
+}
+
+