1 #!/usr/bin/env python 2 ## Copyright (c) 2012 The WebM project authors. All Rights Reserved. 3 ## 4 ## Use of this source code is governed by a BSD-style license 5 ## that can be found in the LICENSE file in the root of the source 6 ## tree. An additional intellectual property rights grant can be found 7 ## in the file PATENTS. All contributing project authors may 8 ## be found in the AUTHORS file in the root of the source tree. 9 ## 10 """Classes for representing diff pieces.""" 11 12 __author__ = "jkoleszar (at] google.com" 13 14 import re 15 16 17 class DiffLines(object): 18 """A container for one half of a diff.""" 19 20 def __init__(self, filename, offset, length): 21 self.filename = filename 22 self.offset = offset 23 self.length = length 24 self.lines = [] 25 self.delta_line_nums = [] 26 27 def Append(self, line): 28 l = len(self.lines) 29 if line[0] != " ": 30 self.delta_line_nums.append(self.offset + l) 31 self.lines.append(line[1:]) 32 assert l+1 <= self.length 33 34 def Complete(self): 35 return len(self.lines) == self.length 36 37 def __contains__(self, item): 38 return item >= self.offset and item <= self.offset + self.length - 1 39 40 41 class DiffHunk(object): 42 """A container for one diff hunk, consisting of two DiffLines.""" 43 44 def __init__(self, header, file_a, file_b, start_a, len_a, start_b, len_b): 45 self.header = header 46 self.left = DiffLines(file_a, start_a, len_a) 47 self.right = DiffLines(file_b, start_b, len_b) 48 self.lines = [] 49 50 def Append(self, line): 51 """Adds a line to the DiffHunk and its DiffLines children.""" 52 if line[0] == "-": 53 self.left.Append(line) 54 elif line[0] == "+": 55 self.right.Append(line) 56 elif line[0] == " ": 57 self.left.Append(line) 58 self.right.Append(line) 59 elif line[0] == "\\": 60 # Ignore newline messages from git diff. 61 pass 62 else: 63 assert False, ("Unrecognized character at start of diff line " 64 "%r" % line[0]) 65 self.lines.append(line) 66 67 def Complete(self): 68 return self.left.Complete() and self.right.Complete() 69 70 def __repr__(self): 71 return "DiffHunk(%s, %s, len %d)" % ( 72 self.left.filename, self.right.filename, 73 max(self.left.length, self.right.length)) 74 75 76 def ParseDiffHunks(stream): 77 """Walk a file-like object, yielding DiffHunks as they're parsed.""" 78 79 file_regex = re.compile(r"(\+\+\+|---) (\S+)") 80 range_regex = re.compile(r"@@ -(\d+)(,(\d+))? \+(\d+)(,(\d+))?") 81 hunk = None 82 while True: 83 line = stream.readline() 84 if not line: 85 break 86 87 if hunk is None: 88 # Parse file names 89 diff_file = file_regex.match(line) 90 if diff_file: 91 if line.startswith("---"): 92 a_line = line 93 a = diff_file.group(2) 94 continue 95 if line.startswith("+++"): 96 b_line = line 97 b = diff_file.group(2) 98 continue 99 100 # Parse offset/lengths 101 diffrange = range_regex.match(line) 102 if diffrange: 103 if diffrange.group(2): 104 start_a = int(diffrange.group(1)) 105 len_a = int(diffrange.group(3)) 106 else: 107 start_a = 1 108 len_a = int(diffrange.group(1)) 109 110 if diffrange.group(5): 111 start_b = int(diffrange.group(4)) 112 len_b = int(diffrange.group(6)) 113 else: 114 start_b = 1 115 len_b = int(diffrange.group(4)) 116 117 header = [a_line, b_line, line] 118 hunk = DiffHunk(header, a, b, start_a, len_a, start_b, len_b) 119 else: 120 # Add the current line to the hunk 121 hunk.Append(line) 122 123 # See if the whole hunk has been parsed. If so, yield it and prepare 124 # for the next hunk. 125 if hunk.Complete(): 126 yield hunk 127 hunk = None 128 129 # Partial hunks are a parse error 130 assert hunk is None 131
