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>

2 files changed, 101 insertions, 1 deletions

diff --git a/lib/puppet/util/autoload.rb b/lib/puppet/util/autoload.rb
index 7c176779a..db06ea934 100644
--- a/lib/puppet/util/autoload.rb
+++ b/lib/puppet/util/autoload.rb
@@ -3,9 +3,12 @@ require 'puppet/util/cacher'
 
 # Autoload paths, either based on names or all at once.
 class Puppet::Util::Autoload
+    require 'puppet/util/autoload/file_cache'
+
     include Puppet::Util
     include Puppet::Util::Warnings
     include Puppet::Util::Cacher
+    include Puppet::Util::Autoload::FileCache
 
     @autoloaders = {}
     @loaded = []
@@ -74,7 +77,7 @@ class Puppet::Util::Autoload
 
         searchpath.each do |dir|
             file = File.join(dir, path)
-            next unless FileTest.exist?(file)
+            next unless file_exist?(file)
             begin
                 Kernel.load file, @wrap
                 name = symbolize(name)
diff --git a/lib/puppet/util/autoload/file_cache.rb b/lib/puppet/util/autoload/file_cache.rb
new file mode 100644
index 000000000..6de525a8d
--- /dev/null
+++ b/lib/puppet/util/autoload/file_cache.rb
@@ -0,0 +1,97 @@
+module Puppet::Util::Autoload::FileCache
+    @found_files = {}
+    @missing_files = {}
+    class << self
+        attr_reader :found_files, :missing_files
+    end
+
+    # Only used for testing.
+    def self.clear
+        @found_files.clear
+        @missing_files.clear
+    end
+
+    def found_files
+        Puppet::Util::Autoload::FileCache.found_files
+    end
+
+    def missing_files
+        Puppet::Util::Autoload::FileCache.missing_files
+    end
+
+    def directory_exist?(path)
+        cache = cached_data?(path, :directory?)
+        return cache unless cache.nil?
+
+        begin
+            stat = File.lstat(path)
+            if stat.directory?
+                found_file(path, stat)
+                return true
+            else
+                missing_file(path)
+                return false
+            end
+        rescue Errno::ENOENT
+            missing_file(path)
+            return false
+        end
+    end
+
+    def file_exist?(path)
+        cache = cached_data?(path)
+        return cache unless cache.nil?
+
+        begin
+            stat = File.lstat(path)
+            found_file(path, stat)
+            return true
+        rescue Errno::ENOENT
+            missing_file(path)
+            return false
+        end
+    end
+
+    def found_file?(path, type = nil)
+        if data = found_files[path] and ! data_expired?(data[:time])
+            if type and ! data[:stat].send(type)
+                return false
+            end
+            return true
+        else
+            return false
+        end
+    end
+
+    def found_file(path, stat)
+        found_files[path] = {:stat => stat, :time => Time.now}
+    end
+
+    def missing_file?(path)
+        if time = missing_files[path] and ! data_expired?(time)
+            return true
+        else
+            return false
+        end
+    end
+
+    def missing_file(path)
+        missing_files[path] = Time.now
+    end
+
+    private
+
+    def cached_data?(path, type = nil)
+        if found_file?(path, type)
+            return true
+        elsif missing_file?(path)
+            return false
+        else
+            return nil
+        end
+    end
+
+    def data_expired?(time)
+        Time.now - time > 15
+    end
+end