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Diffstat (limited to 'tools/json_schema_compiler/code.py')
| -rw-r--r-- | tools/json_schema_compiler/code.py | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/tools/json_schema_compiler/code.py b/tools/json_schema_compiler/code.py new file mode 100644 index 0000000..4f2a64b --- /dev/null +++ b/tools/json_schema_compiler/code.py @@ -0,0 +1,112 @@ +# Copyright (c) 2012 The Chromium Authors. All rights reserved. +# Use of this source code is governed by a BSD-style license that can be +# found in the LICENSE file. + +class Code(object): + """A convenience object for constructing code. + + Logically each object should be a block of code. All methods except |Render| + and |IsEmpty| return self. + """ + def __init__(self, indent_size=2, comment_length=80): + self._code = [] + self._indent_level = 0 + self._indent_size = indent_size + self._comment_length = comment_length + + def Append(self, line=''): + """Appends a line of code at the current indent level or just a newline if + line is not specified. Trailing whitespace is stripped. + """ + self._code.append(((' ' * self._indent_level) + line).rstrip()) + return self + + def IsEmpty(self): + """Returns True if the Code object is empty. + """ + return not bool(self._code) + + def Concat(self, obj): + """Concatenate another Code object onto this one. Trailing whitespace is + stripped. + + Appends the code at the current indent level. Will fail if there are any + un-interpolated format specifiers eg %s, %(something)s which helps + isolate any strings that haven't been substituted. + """ + if not isinstance(obj, Code): + raise TypeError() + assert self is not obj + for line in obj._code: + # line % () will fail if any substitution tokens are left in line + self._code.append(((' ' * self._indent_level) + line % ()).rstrip()) + + return self + + def Sblock(self, line=''): + """Starts a code block. + + Appends a line of code and then increases the indent level. + """ + self.Append(line) + self._indent_level += self._indent_size + return self + + def Eblock(self, line=''): + """Ends a code block by decreasing and then appending a line (or a blank + line if not given). + """ + # TODO(calamity): Decide if type checking is necessary + #if not isinstance(line, basestring): + # raise TypeError + self._indent_level -= self._indent_size + self.Append(line) + return self + + # TODO(calamity): Make comment its own class or something and Render at + # self.Render() time + def Comment(self, comment): + """Adds the given string as a comment. + + Will split the comment if it's too long. Use mainly for variable length + comments. Otherwise just use code.Append('// ...') for comments. + """ + comment_symbol = '// ' + max_len = self._comment_length - self._indent_level - len(comment_symbol) + while len(comment) >= max_len: + line = comment[0:max_len] + last_space = line.rfind(' ') + if last_space != -1: + line = line[0:last_space] + comment = comment[last_space + 1:] + else: + comment = comment[max_len:] + self.Append(comment_symbol + line) + self.Append(comment_symbol + comment) + return self + + def Substitute(self, d): + """Goes through each line and interpolates using the given dict. + + Raises type error if passed something that isn't a dict + + Use for long pieces of code using interpolation with the same variables + repeatedly. This will reduce code and allow for named placeholders which + are more clear. + """ + if not isinstance(d, dict): + raise TypeError('Passed argument is not a dictionary: ' + d) + for i, line in enumerate(self._code): + # Only need to check %s because arg is a dict and python will allow + # '%s %(named)s' but just about nothing else + if '%s' in self._code[i] or '%r' in self._code[i]: + raise TypeError('"%s" or "%r" found in substitution. ' + 'Named arguments only. Use "%" to escape') + self._code[i] = line % d + return self + + def Render(self): + """Renders Code as a string. + """ + return '\n'.join(self._code) + |