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1 # Copyright (c) 2012 The Chromium Authors. All rights reserved. | 1 # Copyright (c) 2012 The Chromium Authors. All rights reserved. |
2 # Use of this source code is governed by a BSD-style license that can be | 2 # Use of this source code is governed by a BSD-style license that can be |
3 # found in the LICENSE file. | 3 # found in the LICENSE file. |
4 | 4 |
5 class Code(object): | 5 class Code(object): |
6 """A convenience object for constructing code. | 6 """A convenience object for constructing code. |
7 | 7 |
8 Logically each object should be a block of code. All methods except |Render| | 8 Logically each object should be a block of code. All methods except |Render| |
9 and |IsEmpty| return self. | 9 and |IsEmpty| return self. |
10 """ | 10 """ |
11 def __init__(self, indent_size=2, comment_length=80): | 11 def __init__(self, indent_size=2, comment_length=80): |
12 self._code = [] | 12 self._code = [] |
13 self._indent_level = 0 | 13 self._indent_level = 0 |
14 self._indent_size = indent_size | 14 self._indent_size = indent_size |
15 self._comment_length = comment_length | 15 self._comment_length = comment_length |
16 | 16 |
17 def Append(self, line=''): | 17 def Append(self, line='', substitute=True): |
18 """Appends a line of code at the current indent level or just a newline if | 18 """Appends a line of code at the current indent level or just a newline if |
19 line is not specified. Trailing whitespace is stripped. | 19 line is not specified. Trailing whitespace is stripped. |
| 20 |
| 21 substitute: indicated whether this line should be affected by |
| 22 code.Substitute(). |
20 """ | 23 """ |
21 self._code.append(((' ' * self._indent_level) + line).rstrip()) | 24 self._code.append(Line(((' ' * self._indent_level) + line).rstrip(), |
| 25 substitute=substitute)) |
22 return self | 26 return self |
23 | 27 |
24 def IsEmpty(self): | 28 def IsEmpty(self): |
25 """Returns True if the Code object is empty. | 29 """Returns True if the Code object is empty. |
26 """ | 30 """ |
27 return not bool(self._code) | 31 return not bool(self._code) |
28 | 32 |
29 def Concat(self, obj): | 33 def Concat(self, obj): |
30 """Concatenate another Code object onto this one. Trailing whitespace is | 34 """Concatenate another Code object onto this one. Trailing whitespace is |
31 stripped. | 35 stripped. |
32 | 36 |
33 Appends the code at the current indent level. Will fail if there are any | 37 Appends the code at the current indent level. Will fail if there are any |
34 un-interpolated format specifiers eg %s, %(something)s which helps | 38 un-interpolated format specifiers eg %s, %(something)s which helps |
35 isolate any strings that haven't been substituted. | 39 isolate any strings that haven't been substituted. |
36 """ | 40 """ |
37 if not isinstance(obj, Code): | 41 if not isinstance(obj, Code): |
38 raise TypeError(type(obj)) | 42 raise TypeError(type(obj)) |
39 assert self is not obj | 43 assert self is not obj |
40 for line in obj._code: | 44 for line in obj._code: |
41 try: | 45 try: |
42 # line % () will fail if any substitution tokens are left in line | 46 # line % () will fail if any substitution tokens are left in line |
43 self._code.append(((' ' * self._indent_level) + line % ()).rstrip()) | 47 if line.substitute: |
| 48 line.value %= () |
44 except TypeError: | 49 except TypeError: |
45 raise TypeError('Unsubstituted value when concatting\n' + line) | 50 raise TypeError('Unsubstituted value when concatting\n' + line) |
| 51 except ValueError: |
| 52 raise ValueError('Stray % character when concatting\n' + line) |
| 53 self.Append(line.value, line.substitute) |
46 | 54 |
47 return self | 55 return self |
48 | 56 |
49 def Sblock(self, line=''): | 57 def Sblock(self, line=''): |
50 """Starts a code block. | 58 """Starts a code block. |
51 | 59 |
52 Appends a line of code and then increases the indent level. | 60 Appends a line of code and then increases the indent level. |
53 """ | 61 """ |
54 self.Append(line) | 62 self.Append(line) |
55 self._indent_level += self._indent_size | 63 self._indent_level += self._indent_size |
56 return self | 64 return self |
57 | 65 |
58 def Eblock(self, line=''): | 66 def Eblock(self, line=''): |
59 """Ends a code block by decreasing and then appending a line (or a blank | 67 """Ends a code block by decreasing and then appending a line (or a blank |
60 line if not given). | 68 line if not given). |
61 """ | 69 """ |
62 # TODO(calamity): Decide if type checking is necessary | 70 # TODO(calamity): Decide if type checking is necessary |
63 #if not isinstance(line, basestring): | 71 #if not isinstance(line, basestring): |
64 # raise TypeError | 72 # raise TypeError |
65 self._indent_level -= self._indent_size | 73 self._indent_level -= self._indent_size |
66 self.Append(line) | 74 self.Append(line) |
67 return self | 75 return self |
68 | 76 |
69 # TODO(calamity): Make comment its own class or something and Render at | 77 def Comment(self, comment, comment_prefix='// '): |
70 # self.Render() time | |
71 def Comment(self, comment): | |
72 """Adds the given string as a comment. | 78 """Adds the given string as a comment. |
73 | 79 |
74 Will split the comment if it's too long. Use mainly for variable length | 80 Will split the comment if it's too long. Use mainly for variable length |
75 comments. Otherwise just use code.Append('// ...') for comments. | 81 comments. Otherwise just use code.Append('// ...') for comments. |
| 82 |
| 83 Unaffected by code.Substitute(). |
76 """ | 84 """ |
77 comment_symbol = '// ' | 85 max_len = self._comment_length - self._indent_level - len(comment_prefix) |
78 max_len = self._comment_length - self._indent_level - len(comment_symbol) | |
79 while len(comment) >= max_len: | 86 while len(comment) >= max_len: |
80 line = comment[0:max_len] | 87 line = comment[0:max_len] |
81 last_space = line.rfind(' ') | 88 last_space = line.rfind(' ') |
82 if last_space != -1: | 89 if last_space != -1: |
83 line = line[0:last_space] | 90 line = line[0:last_space] |
84 comment = comment[last_space + 1:] | 91 comment = comment[last_space + 1:] |
85 else: | 92 else: |
86 comment = comment[max_len:] | 93 comment = comment[max_len:] |
87 self.Append(comment_symbol + line) | 94 self.Append(comment_prefix + line, substitute=False) |
88 self.Append(comment_symbol + comment) | 95 self.Append(comment_prefix + comment, substitute=False) |
89 return self | 96 return self |
90 | 97 |
91 def Substitute(self, d): | 98 def Substitute(self, d): |
92 """Goes through each line and interpolates using the given dict. | 99 """Goes through each line and interpolates using the given dict. |
93 | 100 |
94 Raises type error if passed something that isn't a dict | 101 Raises type error if passed something that isn't a dict |
95 | 102 |
96 Use for long pieces of code using interpolation with the same variables | 103 Use for long pieces of code using interpolation with the same variables |
97 repeatedly. This will reduce code and allow for named placeholders which | 104 repeatedly. This will reduce code and allow for named placeholders which |
98 are more clear. | 105 are more clear. |
99 """ | 106 """ |
100 if not isinstance(d, dict): | 107 if not isinstance(d, dict): |
101 raise TypeError('Passed argument is not a dictionary: ' + d) | 108 raise TypeError('Passed argument is not a dictionary: ' + d) |
102 for i, line in enumerate(self._code): | 109 for i, line in enumerate(self._code): |
103 # Only need to check %s because arg is a dict and python will allow | 110 if self._code[i].substitute: |
104 # '%s %(named)s' but just about nothing else | 111 # Only need to check %s because arg is a dict and python will allow |
105 if '%s' in self._code[i] or '%r' in self._code[i]: | 112 # '%s %(named)s' but just about nothing else |
106 raise TypeError('"%s" or "%r" found in substitution. ' | 113 if '%s' in self._code[i].value or '%r' in self._code[i].value: |
107 'Named arguments only. Use "%" to escape') | 114 raise TypeError('"%s" or "%r" found in substitution. ' |
108 self._code[i] = line % d | 115 'Named arguments only. Use "%" to escape') |
| 116 self._code[i].value = line.value % d |
| 117 self._code[i].substitute = False |
109 return self | 118 return self |
110 | 119 |
111 def Render(self): | 120 def Render(self): |
112 """Renders Code as a string. | 121 """Renders Code as a string. |
113 """ | 122 """ |
114 return '\n'.join(self._code) | 123 return '\n'.join([l.value for l in self._code]) |
115 | 124 |
| 125 class Line(object): |
| 126 """A line of code. |
| 127 """ |
| 128 def __init__(self, value, substitute=True): |
| 129 self.value = value |
| 130 self.substitute = substitute |
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