Split out the filename operations; Morf -> CodeUnit.

--HG--
rename : coverage/morf.py => coverage/codeunit.py

1 files changed, 65 insertions, 0 deletions

diff --git a/coverage/files.py b/coverage/files.py
new file mode 100644
index 00000000..625357c3
--- /dev/null
+++ b/coverage/files.py
@@ -0,0 +1,65 @@
+"""File wrangling."""
+
+import os, sys
+
+class FileWrangler:
+    """Understand how filenames work."""
+
+    def __init__(self):
+        self.relative_dir = self.abs_file(os.curdir) + os.sep
+
+        # Cache of results of calling the canonical_filename() method, to
+        # avoid duplicating work.
+        self.canonical_filename_cache = {}
+
+    def abs_file(self, filename):
+        """ Helper function to turn a filename into an absolute normalized
+            filename.
+        """
+        return os.path.normcase(os.path.abspath(os.path.realpath(filename)))
+
+    def relative_filename(self, filename):
+        """ Convert filename to relative filename from self.relative_dir.
+        """
+        return filename.replace(self.relative_dir, "")
+
+    def canonical_filename(self, filename):
+        """Return a canonical filename for `filename`.
+        
+        An absolute path with no redundant components and normalized case.
+        
+        """
+        if not self.canonical_filename_cache.has_key(filename):
+            f = filename
+            if os.path.isabs(f) and not os.path.exists(f):
+                if not self.get_zip_data(f):
+                    f = os.path.basename(f)
+            if not os.path.isabs(f):
+                for path in [os.curdir] + sys.path:
+                    g = os.path.join(path, f)
+                    if os.path.exists(g):
+                        f = g
+                        break
+            cf = self.abs_file(f)
+            self.canonical_filename_cache[filename] = cf
+        return self.canonical_filename_cache[filename]
+
+    def get_zip_data(self, filename):
+        """ Get data from `filename` if it is a zip file path, or return None
+            if it is not.
+        """
+        import zipimport
+        markers = ['.zip'+os.sep, '.egg'+os.sep]
+        for marker in markers:
+            if marker in filename:
+                parts = filename.split(marker)
+                try:
+                    zi = zipimport.zipimporter(parts[0]+marker[:-1])
+                except zipimport.ZipImportError:
+                    continue
+                try:
+                    data = zi.get_data(parts[1])
+                except IOError:
+                    continue
+                return data
+        return None