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[cffLib] another implementation: prevent *Converter.read from changing file positions

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This commit is contained in:
derwind 2018-02-23 01:03:37 +09:00
parent 91fc3c5c41
commit b9eb1b235f
1 changed files with 27 additions and 32 deletions
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59
Lib/fontTools/cffLib/__init__.py
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@ -1027,9 +1027,22 @@ def buildConverters(table):
return d
class SimpleConverter(object):
class BaseConverter(object):
def read(self, parent, value):
file = parent.file
pos = file.tell()
try:
return self._read(parent, value)
finally:
file.seek(pos)
def _read(self, parent, value):
raise NotImplementedError
class SimpleConverter(BaseConverter):
def _read(self, parent, value):
return value
def write(self, parent, value):
@ -1045,7 +1058,7 @@ class SimpleConverter(object):
class ASCIIConverter(SimpleConverter):
def read(self, parent, value):
def _read(self, parent, value):
return tostr(value, encoding='ascii')
def write(self, parent, value):
@ -1061,7 +1074,7 @@ class ASCIIConverter(SimpleConverter):
class Latin1Converter(SimpleConverter):
def read(self, parent, value):
def _read(self, parent, value):
return tostr(value, encoding='latin1')
def write(self, parent, value):
@ -1177,10 +1190,9 @@ class PrivateDictConverter(TableConverter):
def getClass(self):
return PrivateDict
def read(self, parent, value):
def _read(self, parent, value):
size, offset = value
file = parent.file
pos = file.tell()
isCFF2 = parent._isCFF2
try:
vstore = parent.vstore
@ -1192,7 +1204,6 @@ class PrivateDictConverter(TableConverter):
data = file.read(size)
assert len(data) == size
priv.decompile(data)
file.seek(pos)
return priv
def write(self, parent, value):
@ -1204,14 +1215,11 @@ class SubrsConverter(TableConverter):
def getClass(self):
return SubrsIndex
def read(self, parent, value):
def _read(self, parent, value):
file = parent.file
pos = file.tell()
isCFF2 = parent._isCFF2
file.seek(parent.offset + value) # Offset(self)
subrIndex = SubrsIndex(file, isCFF2=isCFF2)
file.seek(pos)
return subrIndex
return SubrsIndex(file, isCFF2=isCFF2)
def write(self, parent, value):
return 0 # dummy value
@ -1219,9 +1227,8 @@ class SubrsConverter(TableConverter):
class CharStringsConverter(TableConverter):
def read(self, parent, value):
def _read(self, parent, value):
file = parent.file
pos = file.tell()
isCFF2 = parent._isCFF2
charset = parent.charset
globalSubrs = parent.GlobalSubrs
@ -1238,7 +1245,6 @@ class CharStringsConverter(TableConverter):
file.seek(value) # Offset(0)
charStrings = CharStrings(
file, charset, globalSubrs, private, fdSelect, fdArray, isCFF2=isCFF2)
file.seek(pos)
return charStrings
def write(self, parent, value):
@ -1265,13 +1271,12 @@ class CharStringsConverter(TableConverter):
return charStrings
class CharsetConverter(object):
def read(self, parent, value):
class CharsetConverter(BaseConverter):
def _read(self, parent, value):
isCID = hasattr(parent, "ROS")
if value > 2:
numGlyphs = parent.numGlyphs
file = parent.file
pos = file.tell()
file.seek(value)
log.log(DEBUG, "loading charset at %s", value)
format = readCard8(file)
@ -1283,7 +1288,6 @@ class CharsetConverter(object):
raise NotImplementedError
assert len(charset) == numGlyphs
log.log(DEBUG, " charset end at %s", file.tell())
file.seek(pos)
else: # offset == 0 -> no charset data.
if isCID or "CharStrings" not in parent.rawDict:
# We get here only when processing fontDicts from the FDArray of
@ -1473,7 +1477,7 @@ class EncodingCompiler(object):
class EncodingConverter(SimpleConverter):
def read(self, parent, value):
def _read(self, parent, value):
if value == 0:
return "StandardEncoding"
elif value == 1:
@ -1481,7 +1485,6 @@ class EncodingConverter(SimpleConverter):
else:
assert value > 1
file = parent.file
pos = file.tell()
file.seek(value)
log.log(DEBUG, "loading Encoding at %s", value)
fmt = readCard8(file)
@ -1489,14 +1492,12 @@ class EncodingConverter(SimpleConverter):
if haveSupplement:
raise NotImplementedError("Encoding supplements are not yet supported")
fmt = fmt & 0x7f
# save file position against lazy-load of charset
if fmt == 0:
encoding = parseEncoding0(parent.charset, file, haveSupplement,
parent.strings)
elif fmt == 1:
encoding = parseEncoding1(parent.charset, file, haveSupplement,
parent.strings)
file.seek(pos)
return encoding
def write(self, parent, value):
@ -1618,20 +1619,18 @@ def packEncoding1(charset, encoding, strings):
class FDArrayConverter(TableConverter):
def read(self, parent, value):
def _read(self, parent, value):
try:
vstore = parent.VarStore
except AttributeError:
vstore = None
file = parent.file
pos = file.tell()
isCFF2 = parent._isCFF2
file.seek(value)
fdArray = FDArrayIndex(file, isCFF2=isCFF2)
fdArray.vstore = vstore
fdArray.strings = parent.strings
fdArray.GlobalSubrs = parent.GlobalSubrs
file.seek(pos)
return fdArray
def write(self, parent, value):
@ -1647,14 +1646,12 @@ class FDArrayConverter(TableConverter):
return fdArray
class FDSelectConverter(object):
class FDSelectConverter(BaseConverter):
def read(self, parent, value):
def _read(self, parent, value):
file = parent.file
pos = file.tell()
file.seek(value)
fdSelect = FDSelect(file, parent.numGlyphs)
file.seek(pos)
return fdSelect
def write(self, parent, value):
@ -1676,13 +1673,11 @@ class FDSelectConverter(object):
class VarStoreConverter(SimpleConverter):
def read(self, parent, value):
def _read(self, parent, value):
file = parent.file
pos = file.tell()
file.seek(value)
varStore = VarStoreData(file)
varStore.decompile()
file.seek(pos)
return varStore
def write(self, parent, value):