[PATCH 3/8] Teach git var about GIT_EDITOR

[Jonathan Nieder <jrnieder@gmail.com>]

From: Johannes Sixt <j.sixt@viscovery.net>

Expose the command used by launch_editor() for scripts to use.
This should allow one to avoid searching for a proper editor
separately in each command.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 Documentation/git-var.txt |    8 ++++++++
 cache.h                   |    1 +
 editor.c                  |   18 +++++++++++++++---
 var.c                     |   10 ++++++++++
 4 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/Documentation/git-var.txt b/Documentation/git-var.txt
index e2f4c09..89e4b4f 100644
--- a/Documentation/git-var.txt
+++ b/Documentation/git-var.txt
@@ -36,6 +36,14 @@ GIT_AUTHOR_IDENT::
 GIT_COMMITTER_IDENT::
     The person who put a piece of code into git.
 
+GIT_EDITOR::
+    Text editor for use by git commands.  The value is meant to be
+    interpreted by the shell when it is used.  Examples: `~/bin/vi`,
+    `$SOME_ENVIRONMENT_VARIABLE`, `"C:\Program Files\Vim\gvim.exe"
+    --nofork`.  The order of preference is the `$GIT_EDITOR`
+    environment variable, then `core.editor` configuration, then
+    `$VISUAL`, then `$EDITOR`, and then finally 'vi'.
+
 Diagnostics
 -----------
 You don't exist. Go away!::
diff --git a/cache.h b/cache.h
index 96840c7..311cfe1 100644
--- a/cache.h
+++ b/cache.h
@@ -750,6 +750,7 @@ extern const char *git_author_info(int);
 extern const char *git_committer_info(int);
 extern const char *fmt_ident(const char *name, const char *email, const char *date_str, int);
 extern const char *fmt_name(const char *name, const char *email);
+extern const char *git_editor(void);
 
 struct checkout {
 	const char *base_dir;
diff --git a/editor.c b/editor.c
index facd7f2..9dcf95c 100644
--- a/editor.c
+++ b/editor.c
@@ -2,7 +2,7 @@
 #include "strbuf.h"
 #include "run-command.h"
 
-int launch_editor(const char *path, struct strbuf *buffer, const char *const *env)
+const char *git_editor(void)
 {
 	const char *editor, *terminal;
 
@@ -15,18 +15,30 @@ int launch_editor(const char *path, struct strbuf *buffer, const char *const *en
 		editor = getenv("EDITOR");
 
 	terminal = getenv("TERM");
-	if (!editor && (!terminal || !strcmp(terminal, "dumb")))
+	if (!editor && (!terminal || !strcmp(terminal, "dumb"))) {
 		/* Terminal is dumb but no VISUAL nor EDITOR defined. */
-		return error(
+		error(
 		  "No editor specified in GIT_EDITOR, core.editor, VISUAL,\n"
 		  "or EDITOR. Tried to fall back to vi but terminal is dumb.\n"
 		  "Please set one of these variables to an appropriate\n"
 		  "editor or run again with options that will not cause an\n"
 		  "editor to be invoked (e.g., -m or -F for git commit).");
+		return NULL;
+	}
 
 	if (!editor)
 		editor = "vi";
 
+	return editor;
+}
+
+int launch_editor(const char *path, struct strbuf *buffer, const char *const *env)
+{
+	const char *editor = git_editor();
+
+	if (!editor)
+		return -1;
+
 	if (strcmp(editor, ":")) {
 		size_t len = strlen(editor);
 		int i = 0;
diff --git a/var.c b/var.c
index 125c0d1..342dc2c 100644
--- a/var.c
+++ b/var.c
@@ -8,6 +8,15 @@
 
 static const char var_usage[] = "git var [-l | <variable>]";
 
+static const char *editor(int flag)
+{
+	const char *pgm = git_editor();
+
+	if (!pgm && (flag & IDENT_ERROR_ON_NO_NAME))
+		die("cannot find a suitable editor");
+	return pgm;
+}
+
 struct git_var {
 	const char *name;
 	const char *(*read)(int);
@@ -15,6 +24,7 @@ struct git_var {
 static struct git_var git_vars[] = {
 	{ "GIT_COMMITTER_IDENT", git_committer_info },
 	{ "GIT_AUTHOR_IDENT",   git_author_info },
+	{ "GIT_EDITOR", editor },
 	{ "", NULL },
 };
 
-- 
1.6.5.2