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-rw-r--r--misc/ninja_syntax.py94
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diff --git a/misc/ninja_syntax.py b/misc/ninja_syntax.py
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+#!/usr/bin/python
+
+"""Python module for generating .ninja files.
+
+Note that this is emphatically not a required piece of Ninja; it's
+just a helpful utility for build-file-generation systems that already
+use Python.
+"""
+
+import textwrap
+
+class Writer(object):
+ def __init__(self, output, width=78):
+ self.output = output
+ self.width = width
+
+ def newline(self):
+ self.output.write('\n')
+
+ def comment(self, text):
+ for line in textwrap.wrap(text, self.width - 2):
+ self.output.write('# ' + line + '\n')
+
+ def variable(self, key, value, indent=0):
+ self._line('%s = %s' % (key, value), indent)
+
+ def rule(self, name, command, description=None, depfile=None):
+ self._line('rule %s' % name)
+ self.variable('command', command, indent=1)
+ if description:
+ self.variable('description', description, indent=1)
+ if depfile:
+ self.variable('depfile', depfile, indent=1)
+
+ def build(self, outputs, rule, inputs=None, implicit=None, order_only=None,
+ variables=None):
+ outputs = self._as_list(outputs)
+ all_inputs = self._as_list(inputs)[:]
+
+ if implicit:
+ all_inputs.append('|')
+ all_inputs.extend(self._as_list(implicit))
+ if order_only:
+ all_inputs.append('||')
+ all_inputs.extend(self._as_list(order_only))
+
+ self._line('build %s: %s %s' % (' '.join(outputs),
+ rule,
+ ' '.join(all_inputs)))
+
+ if variables:
+ for key, val in variables:
+ self.variable(key, val, indent=1)
+
+ return outputs
+
+ def _line(self, text, indent=0):
+ """Write 'text' word-wrapped at self.width characters."""
+ leading_space = ' ' * indent
+ while len(text) > self.width:
+ # The text is too wide; wrap if possible.
+
+ # Find the rightmost space that would obey our width constraint.
+ available_space = self.width - len(leading_space) - len(' $')
+ space = text.rfind(' ', 0, available_space)
+ if space < 0:
+ # No such space; just use the first space we can find.
+ space = text.find(' ', available_space)
+ if space < 0:
+ # Give up on breaking.
+ break
+
+ self.output.write(leading_space + text[0:space] + ' $\n')
+ text = text[space+1:]
+
+ # Subsequent lines are continuations, so indent them.
+ leading_space = ' ' * (indent+2)
+
+ self.output.write(leading_space + text + '\n')
+
+ def _as_list(self, input):
+ if input is None:
+ return []
+ if isinstance(input, list):
+ return input
+ return [input]
+
+
+def escape(string):
+ """Escape a string such that it can be embedded into a Ninja file without
+ further interpretation."""
+ assert '\n' not in string, 'Ninja syntax does not allow newlines'
+ # We only have one special metacharacter: '$'.
+ return string.replace('$', '$$')