From ba95c01249c5a46c6671f0c5f95c69c13319bdab Mon Sep 17 00:00:00 2001
From: Werner Almesberger <werner@almesberger.net>
Date: Fri, 5 Aug 2016 09:22:37 -0300
Subject: [PATCH] eeshow/: detect if repo is dirty and add history entry with
 commit = NULL

---
 eeshow/git-hist.c | 34 +++++++++++++++++++++++++--------
 eeshow/git-hist.h |  2 +-
 eeshow/git-util.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++
 eeshow/git-util.h |  6 ++++++
 4 files changed, 81 insertions(+), 9 deletions(-)

diff --git a/eeshow/git-hist.c b/eeshow/git-hist.c
index 3367b9d..1baca2f 100644
--- a/eeshow/git-hist.c
+++ b/eeshow/git-hist.c
@@ -142,7 +142,7 @@ bool vcs_git_try(const char *path)
 
 struct hist *vcs_git_hist(const char *path)
 {
-	struct hist *head;
+	struct hist *head, *dirty;
 	git_repository *repo;
 	git_oid oid;
 	const git_error *e;
@@ -173,7 +173,17 @@ struct hist *vcs_git_hist(const char *path)
 	}
 
 	recurse(head, 1, &head);
-	return head;
+
+	if (!git_repo_is_dirty(repo))
+		return head;
+
+	dirty = new_commit(0);
+	dirty->older = alloc_type(struct hist *);
+	dirty->older[0] = head;
+	dirty->n_older = 1;
+	uplink(head, dirty);
+
+	return dirty;
 }
 
 
@@ -182,6 +192,8 @@ const char *vcs_git_summary(struct hist *h)
 	const char *summary;
 	const git_error *e;
 
+	if (!h->commit)
+		return "Uncommitted changes";
 	summary = git_commit_summary(h->commit);
 	if (summary)
 		return summary;
@@ -210,13 +222,19 @@ void dump_hist(struct hist *h)
 	const git_error *e;
 	unsigned i;
 
-	if (git_object_short_id(&buf, (git_object *) h->commit)) {
-		e = giterr_last();
-		fprintf(stderr, "git_object_short_id: %s\n", e->message);
-		exit(1);
+	if (h->commit) {
+		if (git_object_short_id(&buf, (git_object *) h->commit)) {
+			e = giterr_last();
+			fprintf(stderr, "git_object_short_id: %s\n",
+			    e->message);
+			exit(1);
+		}
+		printf("%*s%s  %s\n",
+		    2 * h->branch, "", buf.ptr, vcs_git_summary(h));
+		git_buf_free(&buf);
+	} else {
+		printf("dirty\n");
 	}
-	printf("%*s%s  %s\n", 2 * h->branch, "", buf.ptr, vcs_git_summary(h));
-	git_buf_free(&buf);
 
 	for (i = 0; i != h->n_older; i++)
 		if (h->older[i]->newer[h->older[i]->n_newer - 1] == h)
diff --git a/eeshow/git-hist.h b/eeshow/git-hist.h
index 2d1b628..9c394ed 100644
--- a/eeshow/git-hist.h
+++ b/eeshow/git-hist.h
@@ -19,7 +19,7 @@
 
 
 struct hist {
-	struct git_commit *commit;
+	struct git_commit *commit; /* NULL if uncommitted changes */
 
 	unsigned branch;	/* branch index */
 
diff --git a/eeshow/git-util.c b/eeshow/git-util.c
index 71cf6cd..e3bd2af 100644
--- a/eeshow/git-util.c
+++ b/eeshow/git-util.c
@@ -11,12 +11,60 @@
  */
 
 #include <stdbool.h>
+#include <assert.h>
 
 #include <git2.h>
 
 #include "git-util.h"
 
 
+/*
+ * This seems to be an efficient way for finding out if a repo is dirty.
+ *
+ * http://ben.straub.cc/2013/04/02/libgit2-checkout/
+ *
+ * References:
+ * https://libgit2.github.com/libgit2/#HEAD/group/checkout/git_checkout_index
+ * https://libgit2.github.com/libgit2/#HEAD/type/git_checkout_options
+ * https://github.com/libgit2/libgit2/blob/HEAD/include/git2/checkout.h#L251-295
+ */
+
+
+static int checkout_notify_cb(git_checkout_notify_t why,
+    const char *path, const git_diff_file *baseline,
+    const git_diff_file *target, const git_diff_file *workdir,
+    void *payload)
+{
+	bool *res = payload;
+
+	assert(why == GIT_CHECKOUT_NOTIFY_DIRTY);
+
+	*res = 1;
+	return 0;
+}
+
+
+bool git_repo_is_dirty(git_repository *repo)
+{
+	git_checkout_options opts;
+	bool res = 0;
+
+	/*
+	 * Initialization with GIT_CHECKOUT_OPTIONS_INIT complains about not
+	 * setting checkout_strategy. git_checkout_init_options is fine.
+	 */
+	git_checkout_init_options(&opts, GIT_CHECKOUT_OPTIONS_VERSION);
+	opts.checkout_strategy = GIT_CHECKOUT_NONE;
+		/* let's be explicit about this */
+	opts.notify_flags = GIT_CHECKOUT_NOTIFY_DIRTY;
+	opts.notify_cb = checkout_notify_cb;
+	opts.notify_payload = &res;
+	git_checkout_index(repo, NULL, &opts);
+
+	return res;
+}
+
+
 /*
  * Git documentation says that git_libgit2_init can be called more then once
  * but doesn't quite what happens then, e.g., whether references obtained
diff --git a/eeshow/git-util.h b/eeshow/git-util.h
index 601855a..54641e5 100644
--- a/eeshow/git-util.h
+++ b/eeshow/git-util.h
@@ -13,6 +13,12 @@
 #ifndef GIT_UTIL_H
 #define	GIT_UTIL_H
 
+#include <stdbool.h>
+
+#include <git2.h>
+
+
+bool git_repo_is_dirty(git_repository *repo);
 void git_init_once(void);
 
 #endif /* !GIT_UTIL_H */