1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
|
# -------------------------------------------------------------------------
# Copyright (c) Microsoft Corporation. All rights reserved.
# Licensed under the MIT License. See License.txt in the project root for
# license information.
# --------------------------------------------------------------------------
import threading
def _download_file_chunks(file_service, share_name, directory_name, file_name,
download_size, block_size, progress, start_range, end_range,
stream, max_connections, progress_callback, validate_content,
timeout, operation_context, snapshot):
downloader_class = _ParallelFileChunkDownloader if max_connections > 1 else _SequentialFileChunkDownloader
downloader = downloader_class(
file_service,
share_name,
directory_name,
file_name,
download_size,
block_size,
progress,
start_range,
end_range,
stream,
progress_callback,
validate_content,
timeout,
operation_context,
snapshot,
)
if max_connections > 1:
import concurrent.futures
executor = concurrent.futures.ThreadPoolExecutor(max_connections)
list(executor.map(downloader.process_chunk, downloader.get_chunk_offsets()))
else:
for chunk in downloader.get_chunk_offsets():
downloader.process_chunk(chunk)
class _FileChunkDownloader(object):
def __init__(self, file_service, share_name, directory_name, file_name,
download_size, chunk_size, progress, start_range, end_range,
stream, progress_callback, validate_content, timeout, operation_context, snapshot):
# identifiers for the file
self.file_service = file_service
self.share_name = share_name
self.directory_name = directory_name
self.file_name = file_name
# information on the download range/chunk size
self.chunk_size = chunk_size
self.download_size = download_size
self.start_index = start_range
self.file_end = end_range
# the destination that we will write to
self.stream = stream
# progress related
self.progress_callback = progress_callback
self.progress_total = progress
# parameters for each get file operation
self.validate_content = validate_content
self.timeout = timeout
self.operation_context = operation_context
self.snapshot = snapshot
def get_chunk_offsets(self):
index = self.start_index
while index < self.file_end:
yield index
index += self.chunk_size
def process_chunk(self, chunk_start):
if chunk_start + self.chunk_size > self.file_end:
chunk_end = self.file_end
else:
chunk_end = chunk_start + self.chunk_size
chunk_data = self._download_chunk(chunk_start, chunk_end).content
length = chunk_end - chunk_start
if length > 0:
self._write_to_stream(chunk_data, chunk_start)
self._update_progress(length)
# should be provided by the subclass
def _update_progress(self, length):
pass
# should be provided by the subclass
def _write_to_stream(self, chunk_data, chunk_start):
pass
def _download_chunk(self, chunk_start, chunk_end):
return self.file_service._get_file(
self.share_name,
self.directory_name,
self.file_name,
start_range=chunk_start,
end_range=chunk_end - 1,
validate_content=self.validate_content,
timeout=self.timeout,
_context=self.operation_context,
snapshot=self.snapshot
)
class _ParallelFileChunkDownloader(_FileChunkDownloader):
def __init__(self, file_service, share_name, directory_name, file_name,
download_size, chunk_size, progress, start_range, end_range,
stream, progress_callback, validate_content, timeout, operation_context, snapshot):
super(_ParallelFileChunkDownloader, self).__init__(file_service, share_name, directory_name, file_name,
download_size, chunk_size, progress, start_range, end_range,
stream, progress_callback, validate_content, timeout,
operation_context, snapshot)
# for a parallel download, the stream is always seekable, so we note down the current position
# in order to seek to the right place when out-of-order chunks come in
self.stream_start = stream.tell()
# since parallel operations are going on
# it is essential to protect the writing and progress reporting operations
self.stream_lock = threading.Lock()
self.progress_lock = threading.Lock()
def _update_progress(self, length):
if self.progress_callback is not None:
with self.progress_lock:
self.progress_total += length
total_so_far = self.progress_total
self.progress_callback(total_so_far, self.download_size)
def _write_to_stream(self, chunk_data, chunk_start):
with self.stream_lock:
self.stream.seek(self.stream_start + (chunk_start - self.start_index))
self.stream.write(chunk_data)
class _SequentialFileChunkDownloader(_FileChunkDownloader):
def __init__(self, file_service, share_name, directory_name, file_name, download_size, chunk_size, progress,
start_range, end_range, stream, progress_callback, validate_content, timeout, operation_context,
snapshot):
super(_SequentialFileChunkDownloader, self).__init__(file_service, share_name, directory_name, file_name,
download_size, chunk_size, progress, start_range,
end_range, stream, progress_callback, validate_content,
timeout, operation_context, snapshot)
def _update_progress(self, length):
if self.progress_callback is not None:
self.progress_total += length
self.progress_callback(self.progress_total, self.download_size)
def _write_to_stream(self, chunk_data, chunk_start):
# chunk_start is ignored in the case of sequential download since we cannot seek the destination stream
self.stream.write(chunk_data)
|
