David Rose 4139466fc9 join
2008-11-12 04:05:21 +00:00

283 lines
8.6 KiB
Python

""" This module reimplements Python's file I/O mechanisms using Panda
constructs. This enables Python to interface more easily with Panda's
virtual file system, and it also better-supports Panda's
SIMPLE_THREADS model, by avoiding blocking all threads while waiting
for I/O to complete. """
__all__ = [
'file', 'open', 'listdir', 'walk', 'join'
]
from pandac import PandaModules as pm
import types
_vfs = pm.VirtualFileSystem.getGlobalPtr()
class file:
def __init__(self, filename, mode = 'r', bufsize = None,
autoUnwrap = False):
self.__stream = None
self.__needsVfsClose = False
self.__reader = None
self.__writer = None
self.closed = True
self.encoding = None
self.errors = None
self.__lastWrite = False
self.mode = mode
self.name = None
self.filename = None
self.newlines = None
self.softspace = False
readMode = False
writeMode = False
if isinstance(filename, pm.Istream) or isinstance(filename, pm.Ostream):
# If we were given a stream instead of a filename, assign
# it directly.
self.__stream = filename
readMode = isinstance(filename, pm.Istream)
writeMode = isinstance(filename, pm.Ostream)
elif isinstance(filename, pm.VirtualFile):
# We can also "open" a VirtualFile object for reading.
self.__stream = filename.openReadFile(autoUnwrap)
if not self.__stream:
raise IOError
self.__needsVfsClose = True
readMode = True
else:
# Otherwise, we must have been given a filename. Open it.
if isinstance(filename, types.StringTypes):
# If a raw string is given, assume it's an os-specific
# filename.
filename = pm.Filename.fromOsSpecific(filename)
else:
# If a Filename is given, make a writable copy anyway.
filename = pm.Filename(filename)
self.filename = filename
self.name = filename.toOsSpecific()
binary = False
if 'b' in mode:
# Strip 'b'. This means a binary file.
i = mode.index('b')
mode = mode[:i] + mode[i + 1:]
binary = True
if 'U' in mode:
# Strip 'U'. We don't use it; universal-newline support
# is built into Panda, and can't be changed at runtime.
i = mode.index('U')
mode = mode[:i] + mode[i + 1:]
binary = False
if mode == '':
mode = 'r'
# Per Python docs, we insist this is true.
assert mode[0] in 'rwa'
if binary:
filename.setBinary()
else:
filename.setText()
# Actually open the streams.
if mode == 'w':
self.__stream = pm.Pofstream()
if not filename.openWrite(self.__stream, True):
raise IOError
writeMode = True
elif mode == 'a':
self.__stream = pm.Pofstream()
if not filename.openAppend(self.__stream):
raise IOError
writeMode = True
elif mode == 'w+':
self.__stream = pm.Pfstream()
if not filename.openReadWrite(self.__stream, True):
raise IOError
readMode = True
writeMode = True
elif mode == 'a+':
self.__stream = pm.Pfstream()
if not filename.openReadAppend(self.__stream):
raise IOError
readMode = True
writeMode = True
elif mode == 'r+':
self.__stream = pm.Pfstream()
if not filename.exists():
raise IOError
if not filename.openReadWrite(self.__stream, False):
raise IOError
readMode = True
writeMode = True
elif mode == 'r':
# For strictly read mode (not write or read-write
# mode), we use Panda's VirtualFileSystem.
self.__stream = _vfs.openReadFile(filename, autoUnwrap)
if not self.__stream:
raise IOError
self.__needsVfsClose = True
readMode = True
if readMode:
self.__reader = pm.StreamReader(self.__stream, False)
if writeMode:
self.__writer = pm.StreamWriter(self.__stream, False)
def __del__(self):
self.close()
def close(self):
if self.__needsVfsClose:
_vfs.closeReadFile(self.__stream)
self.__needsVfsClose = False
self.__stream = None
self.__needsVfsClose = False
self.__reader = None
self.__writer = None
def flush(self):
if self.__stream:
self.__stream.flush()
def __iter__(self):
return self
def next(self):
line = self.readline()
if line:
return line
raise StopIteration
def read(self, size = -1):
if not self.__reader:
if not self.__writer:
# The stream is not even open at all.
raise ValueError
# The stream is open only in write mode.
raise IOError
self.__lastWrite = False
if size >= 0:
return self.__reader.extractBytes(size)
else:
# Read to end-of-file.
result = ''
while not self.__stream.eof():
result += self.__reader.extractBytes(1024)
return result
def readline(self, size = -1):
if not self.__reader:
if not self.__writer:
# The stream is not even open at all.
raise ValueError
# The stream is open only in write mode.
raise IOError
self.__lastWrite = False
return self.__reader.readline()
def readlines(self, sizehint = -1):
lines = []
line = self.readline()
while line:
lines.append(line)
line = self.readline()
return lines
xreadlines = readlines
def seek(self, offset, whence = 0):
if self.__reader:
self.__stream.seekg(offset, whence)
if self.__writer:
self.__stream.seekp(offset, whence)
def tell(self):
if self.__lastWrite:
if self.__writer:
return self.__stream.tellp()
else:
if self.__reader:
return self.__stream.tellg()
raise ValueError
def truncate(self):
""" Sorry, this isn't supported by Panda's low-level I/O,
because it isn't supported by the standard C++ library. """
raise NotImplementedError
def write(self, str):
if not self.__writer:
if not self.__reader:
# The stream is not even open at all.
raise ValueError
# The stream is open only in read mode.
raise IOError
self.__writer.appendData(str)
self.__lastWrite = True
def writelines(self, lines):
if not self.__writer:
if not self.__reader:
# The stream is not even open at all.
raise ValueError
# The stream is open only in read mode.
raise IOError
for line in lines:
self.__writer.appendData(line)
self.__lastWrite = True
open = file
def listdir(path):
""" Implements os.listdir over vfs. """
files = []
for file in _vfs.scanDirectory(path):
files.append(file.getFilename().getBasename())
return files
def walk(top, topdown = True, onerror = None, followlinks = True):
""" Implements os.walk over vfs.
Note: we don't support onerror or followlinks; errors are ignored
and links are always followed. """
dirnames = []
filenames = []
for file in _vfs.scanDirectory(top):
if file.isDirectory():
dirnames.append(file.getFilename().getBasename())
else:
filenames.append(file.getFilename().getBasename())
if topdown:
yield (top, dirnames, filenames)
for dir in dirnames:
next = join(top, dir)
for tuple in walk(next, topdown = topdown):
yield tuple
if not topdown:
yield (top, dirnames, filenames)
def join(a, b):
return '%s/%s' % (a, b)