Add column layout skeleton and git-column

A column option string consists of many token separated by either
a space or a  comma. A token belongs to one of three groups:

 - enabling: always, never and auto
 - layout mode: currently plain (which does not layout at all)
 - other future tuning flags

git-column can be used to pipe output to from a command that wants
column layout, but not to mess with its own output code. Simpler output
code can be changed to use column layout code directly.

Thanks-to: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 59 insertions, 0 deletions

diff --git a/builtin/column.c b/builtin/column.c
new file mode 100644
index 0000000000..5ea798a7ca
--- /dev/null
+++ b/builtin/column.c
@@ -0,0 +1,59 @@
+#include "builtin.h"
+#include "cache.h"
+#include "strbuf.h"
+#include "parse-options.h"
+#include "string-list.h"
+#include "column.h"
+
+static const char * const builtin_column_usage[] = {
+	"git column [options]",
+	NULL
+};
+static unsigned int colopts;
+
+static int column_config(const char *var, const char *value, void *cb)
+{
+	return git_column_config(var, value, cb, &colopts);
+}
+
+int cmd_column(int argc, const char **argv, const char *prefix)
+{
+	struct string_list list = STRING_LIST_INIT_DUP;
+	struct strbuf sb = STRBUF_INIT;
+	struct column_options copts;
+	const char *command = NULL, *real_command = NULL;
+	struct option options[] = {
+		OPT_STRING(0, "command", &real_command, "name", "lookup config vars"),
+		OPT_COLUMN(0, "mode", &colopts, "layout to use"),
+		OPT_INTEGER(0, "raw-mode", &colopts, "layout to use"),
+		OPT_INTEGER(0, "width", &copts.width, "Maximum width"),
+		OPT_STRING(0, "indent", &copts.indent, "string", "Padding space on left border"),
+		OPT_INTEGER(0, "nl", &copts.nl, "Padding space on right border"),
+		OPT_INTEGER(0, "padding", &copts.padding, "Padding space between columns"),
+		OPT_END()
+	};
+
+	/* This one is special and must be the first one */
+	if (argc > 1 && !prefixcmp(argv[1], "--command=")) {
+		command = argv[1] + 10;
+		git_config(column_config, (void *)command);
+	} else
+		git_config(column_config, NULL);
+
+	memset(&copts, 0, sizeof(copts));
+	copts.width = term_columns();
+	copts.padding = 1;
+	argc = parse_options(argc, argv, "", options, builtin_column_usage, 0);
+	if (argc)
+		usage_with_options(builtin_column_usage, options);
+	if (real_command || command) {
+		if (!real_command || !command || strcmp(real_command, command))
+			die(_("--command must be the first argument"));
+	}
+	finalize_colopts(&colopts, -1);
+	while (!strbuf_getline(&sb, stdin, '\n'))
+		string_list_append(&list, sb.buf);
+
+	print_columns(&list, colopts, &copts);
+	return 0;
+}