220 lines
7.5 KiB
Python
Executable File
220 lines
7.5 KiB
Python
Executable File
#!/usr/bin/env python3
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# Copyright 2014 The PDFium Authors
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# Use of this source code is governed by a BSD-style license that can be
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# found in the LICENSE file.
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"""Expands a hand-written PDF testcase (template) into a valid PDF file.
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There are several places in a PDF file where byte-offsets are required. This
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script replaces {{name}}-style variables in the input with calculated results
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{{include path/to/file}} - inserts file's contents into stream.
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{{header}} - expands to the header comment required for PDF files.
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{{xref}} - expands to a generated xref table, noting the offset.
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{{trailer}} - expands to a standard trailer with "1 0 R" as the /Root.
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{{trailersize}} - expands to `/Size n`, to be used in non-standard trailers.
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{{startxref} - expands to a startxref directive followed by correct offset.
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{{startxrefobj x y} - expands to a startxref directive followed by correct
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offset pointing to the start of `x y obj`.
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{{object x y}} - expands to `x y obj` declaration, noting the offset.
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{{streamlen}} - expands to `/Length n`.
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"""
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import io
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import optparse
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import os
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import re
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import sys
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# Line Endings.
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WINDOWS_LINE_ENDING = b'\r\n'
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UNIX_LINE_ENDING = b'\n'
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# List of extensions whose line endings should be modified after parsing.
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EXTENSION_OVERRIDE_LINE_ENDINGS = [
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'.js',
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'.fragment',
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'.in',
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'.xml',
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]
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class StreamLenState:
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START = 1
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FIND_STREAM = 2
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FIND_ENDSTREAM = 3
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class TemplateProcessor:
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HEADER_TOKEN = b'{{header}}'
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HEADER_REPLACEMENT = b'%PDF-1.7\n%\xa0\xf2\xa4\xf4'
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XREF_TOKEN = b'{{xref}}'
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XREF_REPLACEMENT = b'xref\n%d %d\n'
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XREF_REPLACEMENT_N = b'%010d %05d n \n'
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XREF_REPLACEMENT_F = b'0000000000 65535 f \n'
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# XREF rows must be exactly 20 bytes - space required.
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assert len(XREF_REPLACEMENT_F) == 20
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TRAILER_TOKEN = b'{{trailer}}'
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TRAILER_REPLACEMENT = b'trailer <<\n /Root 1 0 R\n /Size %d\n>>'
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TRAILERSIZE_TOKEN = b'{{trailersize}}'
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TRAILERSIZE_REPLACEMENT = b'/Size %d'
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STARTXREF_TOKEN = b'{{startxref}}'
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STARTXREF_REPLACEMENT = b'startxref\n%d'
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STARTXREFOBJ_PATTERN = b'\{\{startxrefobj\s+(\d+)\s+(\d+)\}\}'
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OBJECT_PATTERN = b'\{\{object\s+(\d+)\s+(\d+)\}\}'
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OBJECT_REPLACEMENT = b'\g<1> \g<2> obj'
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STREAMLEN_TOKEN = b'{{streamlen}}'
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STREAMLEN_REPLACEMENT = b'/Length %d'
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def __init__(self):
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self.streamlen_state = StreamLenState.START
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self.streamlens = []
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self.offset = 0
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self.xref_offset = 0
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self.max_object_number = 0
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self.objects = {}
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def insert_xref_entry(self, object_number, generation_number):
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self.objects[object_number] = (self.offset, generation_number)
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self.max_object_number = max(self.max_object_number, object_number)
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def generate_xref_table(self):
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result = self.XREF_REPLACEMENT % (0, self.max_object_number + 1)
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for i in range(0, self.max_object_number + 1):
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if i in self.objects:
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result += self.XREF_REPLACEMENT_N % self.objects[i]
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else:
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result += self.XREF_REPLACEMENT_F
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return result
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def preprocess_line(self, line):
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if self.STREAMLEN_TOKEN in line:
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assert self.streamlen_state == StreamLenState.START
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self.streamlen_state = StreamLenState.FIND_STREAM
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self.streamlens.append(0)
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return
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if (self.streamlen_state == StreamLenState.FIND_STREAM and
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line.rstrip() == b'stream'):
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self.streamlen_state = StreamLenState.FIND_ENDSTREAM
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return
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if self.streamlen_state == StreamLenState.FIND_ENDSTREAM:
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if line.rstrip() == b'endstream':
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self.streamlen_state = StreamLenState.START
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else:
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self.streamlens[-1] += len(line)
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def process_line(self, line):
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if self.HEADER_TOKEN in line:
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line = line.replace(self.HEADER_TOKEN, self.HEADER_REPLACEMENT)
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if self.STREAMLEN_TOKEN in line:
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sub = self.STREAMLEN_REPLACEMENT % self.streamlens.pop(0)
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line = re.sub(self.STREAMLEN_TOKEN, sub, line)
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if self.XREF_TOKEN in line:
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self.xref_offset = self.offset
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line = self.generate_xref_table()
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if self.TRAILER_TOKEN in line:
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replacement = self.TRAILER_REPLACEMENT % (self.max_object_number + 1)
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line = line.replace(self.TRAILER_TOKEN, replacement)
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if self.TRAILERSIZE_TOKEN in line:
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replacement = self.TRAILERSIZE_REPLACEMENT % (self.max_object_number + 1)
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line = line.replace(self.TRAILERSIZE_TOKEN, replacement)
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if self.STARTXREF_TOKEN in line:
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replacement = self.STARTXREF_REPLACEMENT % self.xref_offset
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line = line.replace(self.STARTXREF_TOKEN, replacement)
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match = re.match(self.OBJECT_PATTERN, line)
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if match:
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self.insert_xref_entry(int(match.group(1)), int(match.group(2)))
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line = re.sub(self.OBJECT_PATTERN, self.OBJECT_REPLACEMENT, line)
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match = re.match(self.STARTXREFOBJ_PATTERN, line)
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if match:
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(offset, generation_number) = self.objects[int(match.group(1))]
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assert int(match.group(2)) == generation_number
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replacement = self.STARTXREF_REPLACEMENT % offset
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line = re.sub(self.STARTXREFOBJ_PATTERN, replacement, line)
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self.offset += len(line)
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return line
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def expand_file(infile, output_path):
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processor = TemplateProcessor()
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try:
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with open(output_path, 'wb') as outfile:
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preprocessed = io.BytesIO()
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for line in infile:
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preprocessed.write(line)
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processor.preprocess_line(line)
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preprocessed.seek(0)
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for line in preprocessed:
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outfile.write(processor.process_line(line))
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except IOError:
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print('failed to process %s' % input_path, file=sys.stderr)
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def insert_includes(input_path, output_file, visited_set):
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input_path = os.path.normpath(input_path)
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if input_path in visited_set:
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print('Circular inclusion %s, ignoring' % input_path, file=sys.stderr)
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return
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visited_set.add(input_path)
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try:
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_, file_extension = os.path.splitext(input_path)
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override_line_endings = (file_extension in EXTENSION_OVERRIDE_LINE_ENDINGS)
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end_of_file_line_ending = False
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with open(input_path, 'rb') as infile:
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for line in infile:
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match = re.match(b'\s*\{\{include\s+(.+)\}\}', line)
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if match:
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insert_includes(
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os.path.join(
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os.path.dirname(input_path),
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match.group(1).decode('utf-8')), output_file, visited_set)
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else:
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if override_line_endings:
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# Replace CRLF with LF line endings for .in files.
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if line.endswith(WINDOWS_LINE_ENDING):
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line = line.removesuffix(WINDOWS_LINE_ENDING) + UNIX_LINE_ENDING
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end_of_file_line_ending = True
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else:
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end_of_file_line_ending = line.endswith(UNIX_LINE_ENDING)
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output_file.write(line)
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# Ensure the include ends on its own line.
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if not end_of_file_line_ending:
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output_file.write(UNIX_LINE_ENDING)
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except IOError:
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print('failed to include %s' % input_path, file=sys.stderr)
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raise
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visited_set.discard(input_path)
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def main():
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parser = optparse.OptionParser()
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parser.add_option('--output-dir', default='')
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options, args = parser.parse_args()
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for testcase_path in args:
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testcase_filename = os.path.basename(testcase_path)
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testcase_root, _ = os.path.splitext(testcase_filename)
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output_dir = os.path.dirname(testcase_path)
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if options.output_dir:
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output_dir = options.output_dir
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intermediate_stream = io.BytesIO()
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insert_includes(testcase_path, intermediate_stream, set())
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intermediate_stream.seek(0)
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output_path = os.path.join(output_dir, testcase_root + '.pdf')
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expand_file(intermediate_stream, output_path)
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return 0
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if __name__ == '__main__':
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sys.exit(main())
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