move is_outdated to compiler

AUTHORS

@@ -37,6 +37,7 @@ or just made Pipeline more awesome.
  * Peter Baumgartner <pete@lincolnloop.com>
  * Pierre Drescher <pierre.drescher@gmail.com>
  * Remco Wendt <remco@maykinmedia.nl>
+ * Remy Sanchez <remy.sanchez@hyperthese.net>
  * Sam Thomson <sammthomson@gmail.com>
  * Sander Smits <jhmsmits@gmail.com>
  * Sirex <sirexas@gmail.com>

pipeline/compilers/__init__.py

@@ -37,7 +37,7 @@ class Compiler(object):
                         outfile = self.output_path(infile, compiler.output_extension)
                         outdated = True
                     else:
-                        outdated = self.is_outdated(input_path, output_path)
+                        outdated = compiler.is_outdated(infile, outfile)
                     try:
                         compiler.compile_file(infile, outfile, outdated=outdated, force=force)
                     except CompilerError:
@@ -53,12 +53,6 @@ class Compiler(object):
         path = os.path.splitext(path)
         return '.'.join((path[0], extension))
 
-    def is_outdated(self, infile, outfile):
-        try:
-            return self.storage.modified_time(infile) > self.storage.modified_time(outfile)
-        except (OSError, NotImplementedError):
-            return True
-
 
 class CompilerBase(object):
     def __init__(self, verbose, storage):
@@ -80,6 +74,12 @@ class CompilerBase(object):
         file.close()
         return content
 
+    def is_outdated(self, infile, outfile):
+        try:
+            return self.storage.modified_time(infile) > self.storage.modified_time(outfile)
+        except (OSError, NotImplementedError):
+            return True
+
 
 class SubProcessCompiler(CompilerBase):
     def execute_command(self, command, content=None, cwd=None):