Adding caching of file metadata to the autoloader

The cache isn't actually used yet - this just adds
all of the plumbing.

It was found that stat'ing files that didn't exist
could take up to 85% of a run, so this is progress
toward getting rid of those stats.

Signed-off-by: Luke Kanies <luke@madstop.com>

1 files changed, 129 insertions, 0 deletions

diff --git a/spec/unit/util/autoload/file_cache.rb b/spec/unit/util/autoload/file_cache.rb
new file mode 100755
index 000000000..ad4e75f74
--- /dev/null
+++ b/spec/unit/util/autoload/file_cache.rb
@@ -0,0 +1,129 @@
+#!/usr/bin/env ruby
+
+require File.dirname(__FILE__) + '/../../../spec_helper'
+require 'puppet/util/autoload/file_cache'
+
+class FileCacheTester
+    include Puppet::Util::Autoload::FileCache
+end
+
+describe Puppet::Util::Autoload::FileCache do
+    before do
+        @cacher = FileCacheTester.new
+    end
+
+    after do
+        Puppet::Util::Autoload::FileCache.clear
+    end
+
+    describe "when checking whether files exist" do
+        it "should have a method for testing whether a file exists" do
+            @cacher.should respond_to(:file_exist?)
+        end
+
+        it "should use lstat to determine whether a file exists" do
+            File.expects(:lstat).with("/my/file")
+            @cacher.file_exist?("/my/file")
+        end
+
+        it "should consider a file as absent if its lstat fails" do
+            File.expects(:lstat).with("/my/file").raises Errno::ENOENT
+            @cacher.should_not be_file_exist("/my/file")
+        end
+
+        it "should consider a file as present if its lstat succeeds" do
+            File.expects(:lstat).with("/my/file").returns mock("stat")
+            @cacher.should be_file_exist("/my/file")
+        end
+
+        it "should not stat a file twice in quick succession when the file is missing" do
+            File.expects(:lstat).with("/my/file").once.raises Errno::ENOENT
+            @cacher.should_not be_file_exist("/my/file")
+            @cacher.should_not be_file_exist("/my/file")
+        end
+
+        it "should not stat a file twice in quick succession when the file is present" do
+            File.expects(:lstat).with("/my/file").once.returns mock("stat")
+            @cacher.should be_file_exist("/my/file")
+            @cacher.should be_file_exist("/my/file")
+        end
+
+        it "should expire cached data after 15 seconds" do
+            now = Time.now
+
+            later = now + 16
+
+            Time.expects(:now).times(3).returns(now).then.returns(later).then.returns(later)
+            File.expects(:lstat).with("/my/file").times(2).returns(mock("stat")).then.raises Errno::ENOENT
+            @cacher.should be_file_exist("/my/file")
+            @cacher.should_not be_file_exist("/my/file")
+        end
+
+        it "should share cached data across autoload instances" do
+            File.expects(:lstat).with("/my/file").once.returns mock("stat")
+            other = Puppet::Util::Autoload.new("bar", "tmp")
+
+            @cacher.should be_file_exist("/my/file")
+            other.should be_file_exist("/my/file")
+        end
+    end
+
+    describe "when checking whether files exist" do
+        before do
+            @stat = stub 'stat', :directory? => true
+        end
+
+        it "should have a method for determining whether a directory exists" do
+            @cacher.should respond_to(:directory_exist?)
+        end
+
+        it "should use lstat to determine whether a directory exists" do
+            File.expects(:lstat).with("/my/file").returns @stat
+            @cacher.directory_exist?("/my/file")
+        end
+
+        it "should consider a directory as absent if its lstat fails" do
+            File.expects(:lstat).with("/my/file").raises Errno::ENOENT
+            @cacher.should_not be_directory_exist("/my/file")
+        end
+
+        it "should consider a directory as present if its lstat succeeds and the stat is of a directory" do
+            @stat.expects(:directory?).returns true
+            File.expects(:lstat).with("/my/file").returns @stat
+            @cacher.should be_directory_exist("/my/file")
+        end
+
+        it "should consider a directory as absent if its lstat succeeds and the stat is not of a directory" do
+            @stat.expects(:directory?).returns false
+            File.expects(:lstat).with("/my/file").returns @stat
+            @cacher.should_not be_directory_exist("/my/file")
+        end
+
+        it "should not stat a directory twice in quick succession when the file is missing" do
+            File.expects(:lstat).with("/my/file").once.raises Errno::ENOENT
+            @cacher.should_not be_directory_exist("/my/file")
+            @cacher.should_not be_directory_exist("/my/file")
+        end
+
+        it "should not stat a directory twice in quick succession when the file is present" do
+            File.expects(:lstat).with("/my/file").once.returns @stat
+            @cacher.should be_directory_exist("/my/file")
+            @cacher.should be_directory_exist("/my/file")
+        end
+
+        it "should not consider a file to be a directory based on cached data" do
+            @stat.stubs(:directory?).returns false
+            File.stubs(:lstat).with("/my/file").returns @stat
+            @cacher.file_exist?("/my/file")
+            @cacher.should_not be_directory_exist("/my/file")
+        end
+
+        it "should share cached data across autoload instances" do
+            File.expects(:lstat).with("/my/file").once.returns @stat
+            other = Puppet::Util::Autoload.new("bar", "tmp")
+
+            @cacher.should be_directory_exist("/my/file")
+            other.should be_directory_exist("/my/file")
+        end
+    end
+end