1 files changed, 97 insertions, 0 deletions
diff --git a/editor.c b/editor.c
new file mode 100644
index 0000000000..9a9b4e12d1
--- /dev/null
+++ b/editor.c
@@ -0,0 +1,97 @@
+#include "cache.h"
+#include "strbuf.h"
+#include "run-command.h"
+#include "sigchain.h"
+
+#ifndef DEFAULT_EDITOR
+#define DEFAULT_EDITOR "vi"
+#endif
+
+int is_terminal_dumb(void)
+{
+	const char *terminal = getenv("TERM");
+	return !terminal || !strcmp(terminal, "dumb");
+}
+
+const char *git_editor(void)
+{
+	const char *editor = getenv("GIT_EDITOR");
+	int terminal_is_dumb = is_terminal_dumb();
+
+	if (!editor && editor_program)
+		editor = editor_program;
+	if (!editor && !terminal_is_dumb)
+		editor = getenv("VISUAL");
+	if (!editor)
+		editor = getenv("EDITOR");
+
+	if (!editor && terminal_is_dumb)
+		return NULL;
+
+	if (!editor)
+		editor = DEFAULT_EDITOR;
+
+	return editor;
+}
+
+int launch_editor(const char *path, struct strbuf *buffer, const char *const *env)
+{
+	const char *editor = git_editor();
+
+	if (!editor)
+		return error("Terminal is dumb, but EDITOR unset");
+
+	if (strcmp(editor, ":")) {
+		const char *args[] = { editor, real_path(path), NULL };
+		struct child_process p = CHILD_PROCESS_INIT;
+		int ret, sig;
+		int print_waiting_for_editor = advice_waiting_for_editor && isatty(2);
+
+		if (print_waiting_for_editor) {
+			/*
+			 * A dumb terminal cannot erase the line later on. Add a
+			 * newline to separate the hint from subsequent output.
+			 *
+			 * Make sure that our message is separated with a whitespace
+			 * from further cruft that may be written by the editor.
+			 */
+			const char term = is_terminal_dumb() ? '\n' : ' ';
+
+			fprintf(stderr,
+				_("hint: Waiting for your editor to close the file...%c"),
+				term);
+			fflush(stderr);
+		}
+
+		p.argv = args;
+		p.env = env;
+		p.use_shell = 1;
+		if (start_command(&p) < 0)
+			return error("unable to start editor '%s'", editor);
+
+		sigchain_push(SIGINT, SIG_IGN);
+		sigchain_push(SIGQUIT, SIG_IGN);
+		ret = finish_command(&p);
+		sig = ret - 128;
+		sigchain_pop(SIGINT);
+		sigchain_pop(SIGQUIT);
+		if (sig == SIGINT || sig == SIGQUIT)
+			raise(sig);
+		if (ret)
+			return error("There was a problem with the editor '%s'.",
+					editor);
+
+		if (print_waiting_for_editor && !is_terminal_dumb())
+			/*
+			 * Go back to the beginning and erase the entire line to
+			 * avoid wasting the vertical space.
+			 */
+			fputs("\r\033[K", stderr);
+	}
+
+	if (!buffer)
+		return 0;
+	if (strbuf_read_file(buffer, path, 0) < 0)
+		return error_errno("could not read file '%s'", path);
+	return 0;
+}