From fc08c2fe42b963481607f421d0ec76ec9823eec7 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Mon, 29 Jul 2019 20:58:58 +0100
Subject: Periodically check for a new root tree

---
 src/dir.cpp  |  1 +
 src/repo.cpp | 24 ++++++++++++++++++------
 src/repo.h   |  4 ++++
 3 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/src/dir.cpp b/src/dir.cpp
index 012baa5..f59dd92 100644
--- a/src/dir.cpp
+++ b/src/dir.cpp
@@ -14,6 +14,7 @@ GitFS::Directory::Directory(Repo * const r, const std::string & p) :
 GitFS::Git::TreePtr
 GitFS::Directory::getSubtree() const
 {
+	repo->update();
 	if (!git_oid_equal(&subTreeCacheRootId, git_tree_id(repo->tree.get()))) {
 		if (path == "/") {
 			subTreeCache = repo->tree;
diff --git a/src/repo.cpp b/src/repo.cpp
index 0da7e4a..634fe07 100644
--- a/src/repo.cpp
+++ b/src/repo.cpp
@@ -12,21 +12,29 @@ std::string operator/(const std::string & a, const std::string & b)
 GitFS::Repo::Repo(const PropertyReader & properties) :
 	repo(Git::RepositoryOpenBare(properties("gitdir"))),
 	commitish(properties("commitish") / "master"),
+	isBranch(false),
+	resolvedAt(0),
 	gid(properties("gid") / "root"),
 	uid(properties("uid") / "root")
 {
-	git_oid commitId;
 	if (commitish.length() == GIT_OID_HEXSZ) {
-		commitId = Git::OidParse(commitish);
+		commit = Git::CommitLookup(repo, Git::OidParse(commitish));
 	}
 	else {
-		auto ref = Git::Commitish(repo, commitish);
+		ref = Git::Commitish(repo, commitish);
 		isBranch = git_reference_is_branch(ref.get());
-		ref = Git::Resolve(ref);
-		commitId = *git_reference_target(ref.get());
 	}
+	update();
+}
 
-	commit = Git::CommitLookup(repo, commitId);
+void
+GitFS::Repo::update()
+{
+	if (!commit || (isBranch && ref && resolvedAt < std::time(nullptr) - 30)) {
+		commit = Git::CommitLookup(repo,
+				*git_reference_target(Git::Resolve(ref).get()));
+		resolvedAt = std::time(nullptr);
+	}
 	tree = Git::TreeLookup(repo, *git_commit_tree_id(commit.get()));
 }
 
@@ -64,6 +72,7 @@ GitFS::Repo::access(ReqEnv, ::std::string path, int mode, const ::Ice::Current&)
 	if (path == "/") return 0;
 
 	try {
+		update();
 		auto e = Git::TreeEntryByPath(tree, path);
 		const auto emode = git_tree_entry_filemode(e.get());
 
@@ -90,6 +99,7 @@ GitFS::Repo::getattr(ReqEnv, ::std::string path, const ::Ice::Current&)
 		a.mode = S_IFDIR | S_IRUSR | S_IXUSR | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH;
 	}
 	else {
+		update();
 		auto entry = Git::TreeEntryByPath(tree, path);
 		a << *entry;
 		if (S_ISREG(git_tree_entry_filemode(entry.get()))) {
@@ -109,6 +119,7 @@ GitFS::Repo::readlink(ReqEnv, ::std::string path, const ::Ice::Current&)
 {
 	if (path.empty() || path == "/") throw NetFS::SystemError(EINVAL);
 
+	update();
 	auto e = Git::TreeEntryByPath(tree, path);
 	if (!S_ISLNK(git_tree_entry_filemode(e.get()))) throw NetFS::SystemError(EINVAL);
 	auto blob = Git::BlobLookup(repo, *git_tree_entry_id(e.get()));
@@ -123,6 +134,7 @@ GitFS::Repo::open(ReqEnv, ::std::string path, int, const ::Ice::Current& ice)
 	if (path.empty()) throw NetFS::SystemError(EINVAL);
 	if (path == "/") throw NetFS::SystemError(EISDIR);
 
+	update();
 	return Ice::uncheckedCast<NetFS::FilePrx>(ice.adapter->addWithUUID(
 				std::make_shared<Blob>(this, path)));
 }
diff --git a/src/repo.h b/src/repo.h
index adeac94..b5b183c 100644
--- a/src/repo.h
+++ b/src/repo.h
@@ -33,11 +33,15 @@ namespace GitFS {
 			void utimens(ReqEnv env, ::std::string path, long long int atime, long long int atimens, long long int mtime, long long int mtimens, const ::Ice::Current& current) override;
 
 		private:
+			void update();
+
 			friend class Directory;
 			friend class Blob;
 			const Git::RepositoryPtr repo;
 			const std::string commitish;
+			Git::RefPtr ref;
 			bool isBranch;
+			std::time_t resolvedAt;
 			Git::CommitPtr commit;
 			Git::TreePtr tree;
 			const std::string gid, uid;
-- 
cgit v1.2.3