rebase -i: rewrite append_todo_help() in C

This rewrites append_todo_help() from shell to C. It also incorporates
some parts of initiate_action() and complete_action() that also write
help texts to the todo file.

This also introduces the source file rebase-interactive.c. This file
will contain functions necessary for interactive rebase that are too
specific for the sequencer, and is part of libgit.a.

Two flags are added to rebase--helper.c: one to call
append_todo_help() (`--append-todo-help`), and another one to tell
append_todo_help() to write the help text suited for the edit-todo
mode (`--write-edit-todo`).

Finally, append_todo_help() is removed from git-rebase--interactive.sh
to use `rebase--helper --append-todo-help` instead.

Signed-off-by: Alban Gruin <alban.gruin@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 68 insertions, 0 deletions

diff --git a/rebase-interactive.c b/rebase-interactive.c
new file mode 100644
index 0000000..d7996bc
--- /dev/null
+++ b/rebase-interactive.c
@@ -0,0 +1,68 @@
+#include "cache.h"
+#include "commit.h"
+#include "rebase-interactive.h"
+#include "sequencer.h"
+#include "strbuf.h"
+
+int append_todo_help(unsigned edit_todo, unsigned keep_empty)
+{
+	struct strbuf buf = STRBUF_INIT;
+	FILE *todo;
+	int ret;
+	const char *msg = _("\nCommands:\n"
+"p, pick <commit> = use commit\n"
+"r, reword <commit> = use commit, but edit the commit message\n"
+"e, edit <commit> = use commit, but stop for amending\n"
+"s, squash <commit> = use commit, but meld into previous commit\n"
+"f, fixup <commit> = like \"squash\", but discard this commit's log message\n"
+"x, exec <command> = run command (the rest of the line) using shell\n"
+"d, drop <commit> = remove commit\n"
+"l, label <label> = label current HEAD with a name\n"
+"t, reset <label> = reset HEAD to a label\n"
+"m, merge [-C <commit> | -c <commit>] <label> [# <oneline>]\n"
+".       create a merge commit using the original merge commit's\n"
+".       message (or the oneline, if no original merge commit was\n"
+".       specified). Use -c <commit> to reword the commit message.\n"
+"\n"
+"These lines can be re-ordered; they are executed from top to bottom.\n");
+
+	todo = fopen_or_warn(rebase_path_todo(), "a");
+	if (!todo)
+		return 1;
+
+	strbuf_add_commented_lines(&buf, msg, strlen(msg));
+
+	if (get_missing_commit_check_level() == MISSING_COMMIT_CHECK_ERROR)
+		msg = _("\nDo not remove any line. Use 'drop' "
+			 "explicitly to remove a commit.\n");
+	else
+		msg = _("\nIf you remove a line here "
+			 "THAT COMMIT WILL BE LOST.\n");
+
+	strbuf_add_commented_lines(&buf, msg, strlen(msg));
+
+	if (edit_todo)
+		msg = _("\nYou are editing the todo file "
+			"of an ongoing interactive rebase.\n"
+			"To continue rebase after editing, run:\n"
+			"    git rebase --continue\n\n");
+	else
+		msg = _("\nHowever, if you remove everything, "
+			"the rebase will be aborted.\n\n");
+
+	strbuf_add_commented_lines(&buf, msg, strlen(msg));
+
+	if (!keep_empty) {
+		msg = _("Note that empty commits are commented out");
+		strbuf_add_commented_lines(&buf, msg, strlen(msg));
+	}
+
+	ret = fputs(buf.buf, todo);
+	if (ret < 0)
+		error_errno(_("could not append help text to '%s'"), rebase_path_todo());
+
+	fclose(todo);
+	strbuf_release(&buf);
+
+	return ret;
+}