Copy command

Summary:
The `copy` command can be used to copy any `NSURL` or `NSData` to the host machine.

The item will be copied to `/tmp/chisel_copy` and opened in the default application. If copying an `NSURL`, the file will retain its existing name and extension. If copying an `NSData`, a name will be generated with the `.data` extension.

Options:
- `--filename`: Set a name for the file to be copied.
- `--no-open`: Prevent the file from being opened after copying.

Reviewed By: kolinkrewinkel

Differential Revision: D20922370

fbshipit-source-id: a4491f2ef03bf115fce37abdb79e2bd7269635a8

Author: Chris Ellsworth

commands/FBCopyCommands.py

@@ -0,0 +1,116 @@
+#!/usr/bin/python
+
+# Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+from __future__ import print_function
+import os
+import time
+
+import lldb
+import errno
+import fblldbbase as fb
+import fblldbobjecthelpers as objectHelpers
+
+
+def lldbcommands():
+    return [FBCopyCommand()]
+
+
+def _copyFromURL(url, preferredFilename, noOpen):
+    data = fb.evaluateObjectExpression(
+        '(id)[NSData dataWithContentsOfURL:(id){}]'.format(url)
+    )
+    defaultFilename = fb.describeObject(
+        '(id)[[{} pathComponents] lastObject]'.format(url)
+    )
+    _copyFromData(data, defaultFilename, preferredFilename, noOpen)
+
+
+def _copyFromData(data, defaultFilename, preferredFilename, noOpen):
+    directory = '/tmp/chisel_copy/'
+
+    path = directory + (preferredFilename or defaultFilename)
+
+    try:
+        os.makedirs(directory)
+    except OSError as e:
+        if e.errno == errno.EEXIST and os.path.isdir(directory):
+            pass
+        else:
+            raise
+
+    startAddress = fb.evaluateExpression('(void *)[(id)' + data + ' bytes]')
+    length = fb.evaluateExpression('(NSUInteger)[(id)' + data + ' length]')
+
+    address = int(startAddress, 16)
+    length = int(length)
+
+    if not (address or length):
+        print('Could not get data.')
+        return
+
+    process = lldb.debugger.GetSelectedTarget().GetProcess()
+    error = lldb.SBError()
+    mem = process.ReadMemory(address, length, error)
+
+    if error is not None and str(error) != 'success':
+        print(error)
+    else:
+        with open(path, 'wb') as file:
+            file.write(mem)
+            file.close()
+        print(path)
+        if not noOpen:
+            os.system('open ' + path)
+
+
+def _copy(target, preferredFilename, noOpen):
+    target = '(' + target + ')'
+
+    if objectHelpers.isKindOfClass(target, 'NSURL'):
+        _copyFromURL(target, preferredFilename, noOpen)
+    elif objectHelpers.isKindOfClass(target, 'NSData'):
+        _copyFromData(
+            target,
+            time.strftime("%Y-%m-%d-%H-%M-%S", time.gmtime()) + ".data",
+            preferredFilename,
+            noOpen
+        )
+    else:
+        print('{} isn\'t supported. You can copy an NSURL or NSData.'.format(
+            objectHelpers.className(target)
+        ))
+
+
+class FBCopyCommand(fb.FBCommand):
+    def name(self):
+        return 'copy'
+
+    def description(self):
+        return 'Copy data to your Mac.'
+
+    def options(self):
+        return [
+            fb.FBCommandArgument(
+                short='-f', long='--filename', arg='filename',
+                help='The output filename.'
+            ),
+            fb.FBCommandArgument(
+                short='-n', long='--no-open', arg='noOpen',
+                boolean=True, default=False,
+                help='Do not open the file.'
+            ),
+        ]
+
+    def args(self):
+        return [
+            fb.FBCommandArgument(
+                arg='target', type='(id)', help='The object to copy.'
+            )
+        ]
+
+    def run(self, arguments, options):
+        _copy(arguments[0], options.filename, options.noOpen)