| 1 | # ***** BEGIN LICENSE BLOCK *****
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| 2 | # Version: MPL 1.1/GPL 2.0/LGPL 2.1
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| 3 | #
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| 4 | # The contents of this file are subject to the Mozilla Public License Version
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| 5 | # 1.1 (the "License"); you may not use this file except in compliance with
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| 6 | # the License. You may obtain a copy of the License at
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| 7 | # http://www.mozilla.org/MPL/
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| 8 | #
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| 9 | # Software distributed under the License is distributed on an "AS IS" basis,
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| 10 | # WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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| 11 | # for the specific language governing rights and limitations under the
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| 12 | # License.
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| 13 | #
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| 14 | # The Original Code is the Python XPCOM language bindings.
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| 15 | #
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| 16 | # The Initial Developer of the Original Code is
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| 17 | # ActiveState Tool Corp.
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| 18 | # Portions created by the Initial Developer are Copyright (C) 2000, 2001
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| 19 | # the Initial Developer. All Rights Reserved.
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| 20 | #
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| 21 | # Contributor(s):
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| 22 | # Mark Hammond <MarkH@ActiveState.com> (original author)
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| 23 | #
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| 24 | # Alternatively, the contents of this file may be used under the terms of
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| 25 | # either the GNU General Public License Version 2 or later (the "GPL"), or
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| 26 | # the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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| 27 | # in which case the provisions of the GPL or the LGPL are applicable instead
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| 28 | # of those above. If you wish to allow use of your version of this file only
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| 29 | # under the terms of either the GPL or the LGPL, and not to allow others to
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| 30 | # use your version of this file under the terms of the MPL, indicate your
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| 31 | # decision by deleting the provisions above and replace them with the notice
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| 32 | # and other provisions required by the GPL or the LGPL. If you do not delete
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| 33 | # the provisions above, a recipient may use your version of this file under
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| 34 | # the terms of any one of the MPL, the GPL or the LGPL.
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| 35 | #
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| 36 | # ***** END LICENSE BLOCK *****
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| 37 |
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| 38 | """Implementation of Python file objects for Mozilla/xpcom.
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| 39 |
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| 40 | Introduction:
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| 41 | This module defines various class that are implemented using
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| 42 | Mozilla streams. This allows you to open Mozilla URI's, and
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| 43 | treat them as Python file object.
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| 44 |
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| 45 | Example:
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| 46 | >>> file = URIFile("chrome://whatever")
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| 47 | >>> data = file.read(5) # Pass no arg to read everything.
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| 48 |
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| 49 | Known Limitations:
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| 50 | * Not all URL schemes will work from "python.exe" - most notably
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| 51 | "chrome://" and "http://" URLs - this is because a simple initialization of
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| 52 | xpcom by Python does not load up the full set of Mozilla URL handlers.
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| 53 | If you can work out how to correctly initialize the chrome registry and
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| 54 | setup a message queue.
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| 55 |
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| 56 | Known Bugs:
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| 57 | * Only read ("r") mode is supported. Although write ("w") mode doesnt make
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| 58 | sense for HTTP type URLs, it potentially does for file:// etc type ones.
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| 59 | * No concept of text mode vs binary mode. It appears Mozilla takes care of
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| 60 | this internally (ie, all "text/???" mime types are text, rest are binary)
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| 61 |
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| 62 | """
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| 63 |
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| 64 | from xpcom import components, Exception, _xpcom
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| 65 | import os
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| 66 | import threading # for locks.
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| 67 |
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| 68 | NS_RDONLY = 0x01
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| 69 | NS_WRONLY = 0x02
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| 70 | NS_RDWR = 0x04
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| 71 | NS_CREATE_FILE = 0x08
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| 72 | NS_APPEND = 0x10
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| 73 | NS_TRUNCATE = 0x20
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| 74 | NS_SYNC = 0x40
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| 75 | NS_EXCL = 0x80
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| 76 |
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| 77 | # A helper function that may come in useful
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| 78 | def LocalFileToURL(localFileName):
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| 79 | "Convert a filename to an XPCOM nsIFileURL object."
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| 80 | # Create an nsILocalFile
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| 81 | localFile = components.classes["@mozilla.org/file/local;1"] \
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| 82 | .createInstance(components.interfaces.nsILocalFile)
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| 83 | localFile.initWithPath(localFileName)
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| 84 |
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| 85 | # Use the IO Service to create the interface, then QI for a FileURL
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| 86 | io_service = components.classes["@mozilla.org/network/io-service;1"] \
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| 87 | .getService(components.interfaces.nsIIOService)
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| 88 | url = io_service.newFileURI(localFile).queryInterface(components.interfaces.nsIFileURL)
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| 89 | # Setting the "file" attribute causes initialization...
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| 90 | url.file = localFile
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| 91 | return url
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| 92 |
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| 93 | # A base class for file objects.
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| 94 | class _File:
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| 95 | def __init__(self, name_thingy = None, mode="r"):
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| 96 | self.lockob = threading.Lock()
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| 97 | self.inputStream = self.outputStream = None
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| 98 | if name_thingy is not None:
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| 99 | self.init(name_thingy, mode)
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| 100 |
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| 101 | def __del__(self):
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| 102 | self.close()
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| 103 |
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| 104 | # The Moz file streams are not thread safe.
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| 105 | def _lock(self):
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| 106 | self.lockob.acquire()
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| 107 | def _release(self):
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| 108 | self.lockob.release()
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| 109 | def read(self, n = -1):
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| 110 | assert self.inputStream is not None, "Not setup for read!"
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| 111 | self._lock()
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| 112 | try:
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| 113 | return str(self.inputStream.read(n))
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| 114 | finally:
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| 115 | self._release()
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| 116 |
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| 117 | def readlines(self):
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| 118 | # Not part of the xpcom interface, but handy for direct Python users.
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| 119 | # Not 100% faithful, but near enough for now!
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| 120 | lines = self.read().split("\n")
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| 121 | if len(lines) and len(lines[-1]) == 0:
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| 122 | lines = lines[:-1]
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| 123 | return [s+"\n" for s in lines ]
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| 124 |
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| 125 | def write(self, data):
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| 126 | assert self.outputStream is not None, "Not setup for write!"
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| 127 | self._lock()
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| 128 | try:
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| 129 | self.outputStream.write(data, len(data))
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| 130 | finally:
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| 131 | self._release()
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| 132 |
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| 133 | def close(self):
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| 134 | self._lock()
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| 135 | try:
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| 136 | if self.inputStream is not None:
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| 137 | self.inputStream.close()
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| 138 | self.inputStream = None
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| 139 | if self.outputStream is not None:
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| 140 | self.outputStream.close()
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| 141 | self.outputStream = None
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| 142 | self.channel = None
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| 143 | finally:
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| 144 | self._release()
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| 145 |
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| 146 | def flush(self):
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| 147 | self._lock()
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| 148 | try:
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| 149 | if self.outputStream is not None: self.outputStream.flush()
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| 150 | finally:
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| 151 | self._release()
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| 152 |
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| 153 | # A synchronous "file object" used to open a URI.
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| 154 | class URIFile(_File):
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| 155 | def init(self, url, mode="r"):
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| 156 | self.close()
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| 157 | if mode != "r":
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| 158 | raise ValueError("only 'r' mode supported")
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| 159 | io_service = components.classes["@mozilla.org/network/io-service;1"] \
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| 160 | .getService(components.interfaces.nsIIOService)
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| 161 | if hasattr(url, "queryInterface"):
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| 162 | url_ob = url
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| 163 | else:
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| 164 | url_ob = io_service.newURI(url, None, None)
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| 165 | # Mozilla asserts and starts saying "NULL POINTER" if this is wrong!
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| 166 | if not url_ob.scheme:
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| 167 | raise ValueError("The URI '%s' is invalid (no scheme)"
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| 168 | % (url_ob.spec,))
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| 169 | self.channel = io_service.newChannelFromURI(url_ob)
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| 170 | self.inputStream = self.channel.open()
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| 171 |
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| 172 | # A "file object" implemented using Netscape's native file support.
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| 173 | # Based on io.js - http://lxr.mozilla.org/seamonkey/source/xpcom/tests/utils/io.js
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| 174 | # You open this file using a local file name (as a string) so it really is pointless -
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| 175 | # you may as well be using a standard Python file object!
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| 176 | class LocalFile(_File):
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| 177 | def __init__(self, *args):
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| 178 | self.fileIO = None
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| 179 | _File.__init__(self, *args)
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| 180 |
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| 181 | def init(self, name, mode = "r"):
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| 182 | name = os.path.abspath(name) # Moz libraries under Linux fail with relative paths.
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| 183 | self.close()
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| 184 | file = components.classes['@mozilla.org/file/local;1'].createInstance("nsILocalFile")
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| 185 | file.initWithPath(name)
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| 186 | if mode in ["w","a"]:
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| 187 | self.fileIO = components.classes["@mozilla.org/network/file-output-stream;1"].createInstance("nsIFileOutputStream")
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| 188 | if mode== "w":
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| 189 | if file.exists():
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| 190 | file.remove(0)
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| 191 | moz_mode = NS_CREATE_FILE | NS_WRONLY
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| 192 | elif mode=="a":
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| 193 | moz_mode = NS_APPEND
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| 194 | else:
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| 195 | assert 0, "Can't happen!"
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| 196 | self.fileIO.init(file, moz_mode, -1,0)
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| 197 | self.outputStream = self.fileIO
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| 198 | elif mode == "r":
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| 199 | self.fileIO = components.classes["@mozilla.org/network/file-input-stream;1"].createInstance("nsIFileInputStream")
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| 200 | self.fileIO.init(file, NS_RDONLY, -1,0)
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| 201 | self.inputStream = components.classes["@mozilla.org/scriptableinputstream;1"].createInstance("nsIScriptableInputStream")
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| 202 | self.inputStream.init(self.fileIO)
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| 203 | else:
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| 204 | raise ValueError("Unknown mode")
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| 205 |
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| 206 | def close(self):
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| 207 | if self.fileIO is not None:
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| 208 | self.fileIO.close()
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| 209 | self.fileIO = None
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| 210 | _File.close(self)
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| 211 |
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| 212 | def read(self, n = -1):
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| 213 | return _File.read(self, n)
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| 214 |
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| 215 |
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| 216 | ##########################################################
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| 217 | ##
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| 218 | ## Test Code
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| 219 | ##
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| 220 | ##########################################################
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| 221 | def _DoTestRead(file, expected):
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| 222 | # read in a couple of chunks, just to test that our various arg combinations work.
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| 223 | got = file.read(3)
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| 224 | got = got + file.read(300)
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| 225 | got = got + file.read(0)
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| 226 | got = got + file.read()
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| 227 | if got != expected:
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| 228 | raise RuntimeError("Reading '%s' failed - got %d bytes, but expected %d bytes" % (file, len(got), len(expected)))
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| 229 |
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| 230 | def _DoTestBufferRead(file, expected):
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| 231 | # read in a couple of chunks, just to test that our various arg combinations work.
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| 232 | buffer = _xpcom.AllocateBuffer(50)
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| 233 | got = ''
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| 234 | while 1:
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| 235 | # Note - we need to reach into the file object so we
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| 236 | # can get at the native buffer supported function.
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| 237 | num = file.inputStream.read(buffer)
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| 238 | if num == 0:
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| 239 | break
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| 240 | got = got + str(buffer[:num])
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| 241 | if got != expected:
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| 242 | raise RuntimeError("Reading '%s' failed - got %d bytes, but expected %d bytes" % (file, len(got), len(expected)))
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| 243 |
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| 244 | def _TestLocalFile():
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| 245 | import tempfile, os
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| 246 | fname = tempfile.mktemp()
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| 247 | data = "Hello from Python"
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| 248 | test_file = LocalFile(fname, "w")
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| 249 | try:
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| 250 | test_file.write(data)
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| 251 | test_file.close()
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| 252 | # Make sure Python can read it OK.
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| 253 | f = open(fname, "r")
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| 254 | assert f.read() == data, "Eeek - Python could not read the data back correctly!"
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| 255 | f.close()
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| 256 | # For the sake of the test, try a re-init.
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| 257 | test_file.init(fname, "r")
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| 258 | got = str(test_file.read())
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| 259 | assert got == data, got
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| 260 | test_file.close()
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| 261 | # Try reading in chunks.
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| 262 | test_file = LocalFile(fname, "r")
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| 263 | got = test_file.read(10) + test_file.read()
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| 264 | assert got == data, got
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| 265 | test_file.close()
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| 266 | # Open the same file again for writing - this should delete the old one.
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| 267 | if not os.path.isfile(fname):
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| 268 | raise RuntimeError("The file '%s' does not exist, but we are explicitly testing create semantics when it does" % (fname,))
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| 269 | test_file = LocalFile(fname, "w")
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| 270 | test_file.write(data)
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| 271 | test_file.close()
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| 272 | # Make sure Python can read it OK.
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| 273 | f = open(fname, "r")
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| 274 | assert f.read() == data, "Eeek - Python could not read the data back correctly after recreating an existing file!"
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| 275 | f.close()
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| 276 |
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| 277 | # XXX - todo - test "a" mode!
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| 278 | finally:
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| 279 | os.unlink(fname)
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| 280 |
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| 281 | def _TestAll():
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| 282 | # A mini test suite.
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| 283 | # Get a test file, and convert it to a file:// URI.
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| 284 | # check what we read is the same as when
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| 285 | # we read this file "normally"
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| 286 | fname = components.__file__
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| 287 | if fname[-1] in "cCoO": # fix .pyc/.pyo
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| 288 | fname = fname[:-1]
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| 289 | expected = open(fname, "rb").read()
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| 290 | # convert the fname to a URI.
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| 291 | url = LocalFileToURL(fname)
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| 292 | # First try passing a URL as a string.
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| 293 | _DoTestRead( URIFile( url.spec), expected)
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| 294 | # Now with a URL object.
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| 295 | _DoTestRead( URIFile( url ), expected)
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| 296 |
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| 297 | _DoTestBufferRead( URIFile( url ), expected)
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| 298 |
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| 299 | # For the sake of testing, do our pointless, demo object!
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| 300 | _DoTestRead( LocalFile(fname), expected )
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| 301 |
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| 302 | # Now do the full test of our pointless, demo object!
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| 303 | _TestLocalFile()
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| 304 |
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| 305 | def _TestURI(url):
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| 306 | test_file = URIFile(url)
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| 307 | print("Opened file is", test_file)
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| 308 | got = test_file.read()
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| 309 | print("Read %d bytes of data from %r" % (len(got), url))
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| 310 | test_file.close()
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| 311 |
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| 312 | if __name__=='__main__':
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| 313 | import sys
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| 314 | if len(sys.argv) < 2:
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| 315 | print("No URL specified on command line - performing self-test")
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| 316 | _TestAll()
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| 317 | else:
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| 318 | _TestURI(sys.argv[1])
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