webkitpy: Simplify DiffParser, removing support for SVN patches.

third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/diff_parser.py

Index: third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/diff_parser.py
diff --git a/third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/diff_parser.py b/third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/diff_parser.py
index 90fd961b660803ce5bf092fd537f4ba2bc19069f..739131fc4ac23aaaa124516f9ee2c43502a36005 100644
--- a/third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/diff_parser.py
+++ b/third_party/WebKit/Tools/Scripts/webkitpy/common/checkout/diff_parser.py
@@ -33,53 +33,9 @@ import re
 
 _log = logging.getLogger(__name__)
 
-conversion_patterns = (
-    (re.compile(r"^diff --git \w/(.+) \w/(?P<FilePath>.+)"), lambda matched: "Index: " + matched.group('FilePath') + "\n"),
-    (re.compile(r"^new file.*"), lambda matched: "\n"),
-    (re.compile(r"^index (([0-9a-f]{7}\.\.[0-9a-f]{7})|([0-9a-f]{40}\.\.[0-9a-f]{40})) [0-9]{6}"),
-     lambda matched: ("=" * 67) + "\n"),
-    (re.compile(r"^--- \w/(?P<FilePath>.+)"), lambda matched: "--- " + matched.group('FilePath') + "\n"),
-    (re.compile(r"^\+\+\+ \w/(?P<FilePath>.+)"), lambda matched: "+++ " + matched.group('FilePath') + "\n"),
-)
+INDEX_PATTERN = re.compile(r'^diff --git \w/(.+) \w/(?P<FilePath>.+)')
+LINES_CHANGED_PATTERN = re.compile(r"^@@ -(?P<OldStartLine>\d+)(,\d+)? \+(?P<NewStartLine>\d+)(,\d+)? @@")
 
-index_pattern = re.compile(r"^Index: (?P<FilePath>.+)")
-lines_changed_pattern = re.compile(r"^@@ -(?P<OldStartLine>\d+)(,\d+)? \+(?P<NewStartLine>\d+)(,\d+)? @@")
-diff_git_pattern = re.compile(r"^diff --git \w/")
-
-
-def git_diff_to_svn_diff(line):
-    """Converts a git formatted diff line to a svn formatted line.
-
-    Args:
-      line: A string representing a line of the diff.
-    """
-    for pattern, conversion in conversion_patterns:
-        matched = pattern.match(line)
-        if matched:
-            return conversion(matched)
-    return line
-
-
-# This function exists so we can unittest get_diff_converter function
-def svn_diff_to_svn_diff(line):
-    return line
-
-
-def get_diff_converter(lines):
-    """Gets a converter function of diff lines.
-
-    Args:
-      lines: The lines of a diff file.
-             If this line is git formatted, we'll return a
-             converter from git to SVN.
-    """
-    for i, line in enumerate(lines[:-1]):
-        # Stop when we find the first patch
-        if line[:3] == "+++" and lines[i + 1] == "---":
-            break
-        if diff_git_pattern.match(line):
-            return git_diff_to_svn_diff
-    return svn_diff_to_svn_diff
 
 _INITIAL_STATE = 1
 _DECLARED_FILE_PATH = 2
@@ -140,12 +96,10 @@ class DiffParser(object):
         current_file = None
         old_diff_line = None
         new_diff_line = None
-        transform_line = get_diff_converter(diff_input)
         for line in diff_input:
-            line = line.rstrip("\n")
-            line = transform_line(line)
+            line = line.rstrip('\n')
 
-            file_declaration = index_pattern.match(line)
+            file_declaration = INDEX_PATTERN.match(line)
             if file_declaration:
                 filename = file_declaration.group('FilePath')
                 current_file = DiffFile(filename)
@@ -153,7 +107,7 @@ class DiffParser(object):
                 state = _DECLARED_FILE_PATH
                 continue
 
-            lines_changed = lines_changed_pattern.match(line)
+            lines_changed = LINES_CHANGED_PATTERN.match(line)
             if lines_changed:
                 if state != _DECLARED_FILE_PATH and state != _PROCESSING_CHUNK:
                     _log.error('Unexpected line change without file path declaration: %r', line)