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Add a timeout to the PDF metadata writer as it hangs on some PDF files

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This commit is contained in:
Kovid Goyal 2009-04-16 14:39:17 -07:00
parent cf77ec2c4a
commit 4e1f851a44
3 changed files with 64 additions and 42 deletions
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48
src/calibre/ebooks/metadata/pdf.py
View File

@ -2,7 +2,8 @@ __license__ = 'GPL v3'
__copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
'''Read meta information from PDF files'''
import sys, os, StringIO
import sys, os, cStringIO
from threading import Thread
from calibre.ebooks.metadata import MetaInformation, authors_to_string, get_parser
from pyPdf import PdfFileReader, PdfFileWriter
@ -29,25 +30,46 @@ def get_metadata(stream):
print >>sys.stderr, msg.encode('utf8')
return mi
class MetadataWriter(Thread):
def __init__(self, out_pdf, buf):
self.out_pdf = out_pdf
self.buf = buf
Thread.__init__(self)
self.daemon = True
def run(self):
try:
self.out_pdf.write(self.buf)
except RuntimeError:
pass
def set_metadata(stream, mi):
stream.seek(0)
# Use a StringIO object for the pdf because we will want to over
# write it later and if we are working on the stream directly it
# could cause some issues.
raw = StringIO.StringIO(stream.read())
raw = cStringIO.StringIO(stream.read())
orig_pdf = PdfFileReader(raw)
title = mi.title if mi.title else orig_pdf.documentInfo.title
author = authors_to_string(mi.authors) if mi.authors else orig_pdf.documentInfo.author
out_pdf = PdfFileWriter(title=title, author=author)
out_str = cStringIO.StringIO()
writer = MetadataWriter(out_pdf, out_str)
for page in orig_pdf.pages:
out_pdf.addPage(page)
out_str = StringIO.StringIO()
out_pdf.write(out_str)
writer.start()
writer.join(10) # Wait 10 secs for writing to complete
out_pdf.killed = True
writer.join()
if out_pdf.killed:
print 'Failed to set metadata: took too long'
return
stream.seek(0)
stream.truncate()
out_str.seek(0)
@ -59,7 +81,7 @@ def option_parser():
p.remove_option('--category')
p.remove_option('--comment')
return p
def main(args=sys.argv):
#p = option_parser()
#opts, args = p.parse_args(args)
@ -67,14 +89,14 @@ def main(args=sys.argv):
print >>sys.stderr, _('Usage: pdf-meta file.pdf')
print >>sys.stderr, _('No filename specified.')
return 1
stream = open(os.path.abspath(os.path.expanduser(args[1])), 'r+b')
#mi = MetaInformation(opts.title, opts.authors)
#if mi.title or mi.authors:
# set_metadata(stream, mi)
print unicode(get_metadata(stream)).encode('utf-8')
return 0
if __name__ == '__main__':
sys.exit(main())
sys.exit(main())

4
src/pyPdf/generic.py
View File

@ -299,7 +299,7 @@ def readStringFromStream(stream):
elif tok == "t":
tok = "\t"
elif tok == "b":
tok == "\b"
tok = "\b"
elif tok == "f":
tok = "\f"
elif tok == "(":
@ -673,7 +673,7 @@ class RectangleObject(ArrayObject):
def getUpperLeft_x(self):
return self.getLowerLeft_x()
def getUpperLeft_y(self):
return self.getUpperRight_y()

54
src/pyPdf/pdf.py
View File

@ -39,15 +39,12 @@ __author__ = "Mathieu Fenniak"
__author_email__ = "biziqe@mathieu.fenniak.net"
import struct
try:
from cStringIO import StringIO
except ImportError:
from StringIO import StringIO
from cStringIO import StringIO
import filters
import utils
import warnings
from generic import *
from generic import DictionaryObject, NameObject, NumberObject, \
createStringObject, ArrayObject, ByteStringObject, StreamObject, \
IndirectObject, utils, readObject, TextStringObject, BooleanObject, \
RectangleObject, DecodedStreamObject
from utils import readNonWhitespace, readUntilWhitespace, ConvertFunctionsToVirtualList
@ -56,6 +53,7 @@ from utils import readNonWhitespace, readUntilWhitespace, ConvertFunctionsToVirt
# class (typically {@link #PdfFileReader PdfFileReader}).
class PdfFileWriter(object):
def __init__(self,title=u"Unknown",author=u"Unknown"):
self.killed = False
self._header = "%PDF-1.3"
self._objects = [] # array of indirect objects
@ -162,7 +160,7 @@ class PdfFileWriter(object):
# @param stream An object to write the file to. The object must support
# the write method, and the tell method, similar to a file object.
def write(self, stream):
import struct, md5
import md5
externalReferenceMap = {}
self.stack = []
@ -209,11 +207,13 @@ class PdfFileWriter(object):
if hasattr(self, "_encrypt"):
trailer[NameObject("/Encrypt")] = self._encrypt
trailer.writeToStream(stream, None)
# eof
stream.write("\nstartxref\n%s\n%%%%EOF\n" % (xref_location))
def _sweepIndirectReferences(self, externMap, data):
if self.killed:
raise RuntimeError('Writer killed')
if isinstance(data, DictionaryObject):
for key, value in data.items():
origvalue = value
@ -356,8 +356,8 @@ class PdfFileReader(object):
return self.flattenedPages[pageNumber]
##
# Read-only property that accesses the
# {@link #PdfFileReader.getNamedDestinations
# Read-only property that accesses the
# {@link #PdfFileReader.getNamedDestinations
# getNamedDestinations} function.
# <p>
# Stability: Added in v1.10, will exist for all future v1.x releases.
@ -374,7 +374,7 @@ class PdfFileReader(object):
if retval == None:
retval = {}
catalog = self.trailer["/Root"]
# get the name tree
if catalog.has_key("/Dests"):
tree = catalog["/Dests"]
@ -382,7 +382,7 @@ class PdfFileReader(object):
names = catalog['/Names']
if names.has_key("/Dests"):
tree = names['/Dests']
if tree == None:
return retval
@ -420,17 +420,17 @@ class PdfFileReader(object):
if outlines == None:
outlines = []
catalog = self.trailer["/Root"]
# get the outline dictionary and named destinations
if catalog.has_key("/Outlines"):
lines = catalog["/Outlines"]
if lines.has_key("/First"):
node = lines["/First"]
self._namedDests = self.getNamedDestinations()
if node == None:
return outlines
# see if there are any more outlines
while 1:
outline = self._buildOutline(node)
@ -454,10 +454,10 @@ class PdfFileReader(object):
page, typ = array[0:2]
array = array[2:]
return Destination(title, page, typ, *array)
def _buildOutline(self, node):
dest, title, outline = None, None, None
if node.has_key("/A") and node.has_key("/Title"):
# Action, section 8.5 (only type GoTo supported)
title = node["/Title"]
@ -951,7 +951,7 @@ class PageObject(DictionaryObject):
def _pushPopGS(contents, pdf):
# adds a graphics state "push" and "pop" to the beginning and end
# of a content stream. This isolates it from changes such as
# of a content stream. This isolates it from changes such as
# transformation matricies.
stream = ContentStream(contents, pdf)
stream.operations.insert(0, [[], "q"])
@ -1291,7 +1291,7 @@ class Destination(DictionaryObject):
self[NameObject("/Title")] = title
self[NameObject("/Page")] = page
self[NameObject("/Type")] = typ
# from table 8.2 of the PDF 1.6 reference.
if typ == "/XYZ":
(self[NameObject("/Left")], self[NameObject("/Top")],
@ -1307,7 +1307,7 @@ class Destination(DictionaryObject):
pass
else:
raise utils.PdfReadError("Unknown Destination Type: %r" % typ)
##
# Read-only property accessing the destination title.
# @return A string.
@ -1474,25 +1474,25 @@ def _alg35(password, rev, keylen, owner_entry, p_entry, id1_entry, metadata_encr
# described in Algorithm 3.2.
key = _alg32(password, rev, keylen, owner_entry, p_entry, id1_entry)
# 2. Initialize the MD5 hash function and pass the 32-byte padding string
# shown in step 1 of Algorithm 3.2 as input to this function.
# shown in step 1 of Algorithm 3.2 as input to this function.
import md5
m = md5.new()
m.update(_encryption_padding)
# 3. Pass the first element of the file's file identifier array (the value
# of the ID entry in the document's trailer dictionary; see Table 3.13 on
# page 73) to the hash function and finish the hash. (See implementation
# note 25 in Appendix H.)
# note 25 in Appendix H.)
m.update(id1_entry)
md5_hash = m.digest()
# 4. Encrypt the 16-byte result of the hash, using an RC4 encryption
# function with the encryption key from step 1.
# function with the encryption key from step 1.
val = utils.RC4_encrypt(key, md5_hash)
# 5. Do the following 19 times: Take the output from the previous
# invocation of the RC4 function and pass it as input to a new invocation
# of the function; use an encryption key generated by taking each byte of
# the original encryption key (obtained in step 2) and performing an XOR
# operation between that byte and the single-byte value of the iteration
# counter (from 1 to 19).
# counter (from 1 to 19).
for i in range(1, 20):
new_key = ''
for l in range(len(key)):
@ -1500,7 +1500,7 @@ def _alg35(password, rev, keylen, owner_entry, p_entry, id1_entry, metadata_encr
val = utils.RC4_encrypt(new_key, val)
# 6. Append 16 bytes of arbitrary padding to the output from the final
# invocation of the RC4 function and store the 32-byte result as the value
# of the U entry in the encryption dictionary.
# of the U entry in the encryption dictionary.
# (implementator note: I don't know what "arbitrary padding" is supposed to
# mean, so I have used null bytes. This seems to match a few other
# people's implementations)