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1 // Copyright 2015 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #include <stddef.h> | |
6 #include <stdint.h> | |
7 | |
8 #include <algorithm> | |
9 | |
10 #include "base/numerics/safe_math.h" | |
11 #include "storage/browser/blob/blob_async_transport_request_builder.h" | |
12 #include "storage/common/blob_storage/blob_storage_constants.h" | |
13 | |
14 namespace storage { | |
15 namespace { | |
16 bool IsBytes(DataElement::Type type) { | |
17 return type == DataElement::TYPE_BYTES || | |
18 type == DataElement::TYPE_BYTES_DESCRIPTION; | |
19 } | |
20 | |
21 // This is the general template that each strategy below implements. See the | |
22 // ForEachWithSegment method for a description of how these are called. | |
23 // class BlobSegmentVisitor { | |
24 // public: | |
25 // typedef ___ SizeType; | |
26 // void VisitBytesSegment(size_t element_index, uint64_t element_offset, | |
27 // size_t segment_index, uint64_t segment_offset, | |
28 // uint64_t size); | |
29 // void VisitNonBytesSegment(const DataElement& element, size_t element_idx); | |
30 // void Done(); | |
31 // }; | |
32 | |
33 // This class handles the logic of how transported memory is going to be | |
34 // represented as storage in the browser. The main idea is that all the memory | |
35 // is now packed into file chunks, and the browser items will just reference | |
36 // the file with offsets and sizes. | |
37 class FileStorageStrategy { | |
38 public: | |
39 FileStorageStrategy( | |
40 std::vector<BlobAsyncTransportRequestBuilder::RendererMemoryItemRequest>* | |
41 requests, | |
42 BlobDataBuilder* builder) | |
43 : requests(requests), builder(builder), current_item_index(0) {} | |
44 | |
45 ~FileStorageStrategy() {} | |
46 | |
47 void VisitBytesSegment(size_t element_index, | |
48 uint64_t element_offset, | |
49 size_t segment_index, | |
50 uint64_t segment_offset, | |
51 uint64_t size) { | |
52 BlobAsyncTransportRequestBuilder::RendererMemoryItemRequest request; | |
53 request.browser_item_index = current_item_index; | |
54 request.browser_item_offset = 0; | |
55 request.message.request_number = requests->size(); | |
56 request.message.transport_strategy = IPCBlobItemRequestStrategy::FILE; | |
57 request.message.renderer_item_index = element_index; | |
58 request.message.renderer_item_offset = element_offset; | |
59 request.message.size = size; | |
60 request.message.handle_index = segment_index; | |
61 request.message.handle_offset = segment_offset; | |
62 | |
63 requests->push_back(request); | |
64 builder->AppendFutureFile(segment_offset, size, segment_index); | |
65 current_item_index++; | |
66 } | |
67 | |
68 void VisitNonBytesSegment(const DataElement& element, size_t element_index) { | |
69 builder->AppendIPCDataElement(element); | |
70 current_item_index++; | |
71 } | |
72 | |
73 void Done() {} | |
74 | |
75 std::vector<BlobAsyncTransportRequestBuilder::RendererMemoryItemRequest>* | |
76 requests; | |
77 BlobDataBuilder* builder; | |
78 | |
79 size_t current_item_index; | |
80 }; | |
81 | |
82 // This class handles the logic of storing memory that is transported as | |
83 // consolidated shared memory. | |
84 class SharedMemoryStorageStrategy { | |
85 public: | |
86 SharedMemoryStorageStrategy( | |
87 size_t max_segment_size, | |
88 std::vector<BlobAsyncTransportRequestBuilder::RendererMemoryItemRequest>* | |
89 requests, | |
90 BlobDataBuilder* builder) | |
91 : requests(requests), | |
92 max_segment_size(max_segment_size), | |
93 builder(builder), | |
94 current_item_size(0), | |
95 current_item_index(0) {} | |
96 ~SharedMemoryStorageStrategy() {} | |
97 | |
98 void VisitBytesSegment(size_t element_index, | |
99 uint64_t element_offset, | |
100 size_t segment_index, | |
101 uint64_t segment_offset, | |
102 uint64_t size) { | |
103 if (current_item_size + size > max_segment_size) { | |
104 builder->AppendFutureData(current_item_size); | |
105 current_item_index++; | |
106 current_item_size = 0; | |
107 } | |
108 BlobAsyncTransportRequestBuilder::RendererMemoryItemRequest request; | |
109 request.browser_item_index = current_item_index; | |
110 request.browser_item_offset = current_item_size; | |
111 request.message.request_number = requests->size(); | |
112 request.message.transport_strategy = | |
113 IPCBlobItemRequestStrategy::SHARED_MEMORY; | |
114 request.message.renderer_item_index = element_index; | |
115 request.message.renderer_item_offset = element_offset; | |
116 request.message.size = size; | |
117 request.message.handle_index = segment_index; | |
118 request.message.handle_offset = segment_offset; | |
119 | |
120 requests->push_back(request); | |
121 current_item_size += size; | |
122 } | |
123 | |
124 void VisitNonBytesSegment(const DataElement& element, size_t element_index) { | |
125 if (current_item_size != 0) { | |
126 builder->AppendFutureData(current_item_size); | |
127 current_item_index++; | |
128 } | |
129 builder->AppendIPCDataElement(element); | |
130 current_item_index++; | |
131 current_item_size = 0; | |
132 } | |
133 | |
134 void Done() { | |
135 if (current_item_size != 0) { | |
136 builder->AppendFutureData(current_item_size); | |
137 } | |
138 } | |
139 | |
140 std::vector<BlobAsyncTransportRequestBuilder::RendererMemoryItemRequest>* | |
141 requests; | |
142 | |
143 size_t max_segment_size; | |
144 BlobDataBuilder* builder; | |
145 size_t current_item_size; | |
146 uint64_t current_item_index; | |
147 }; | |
148 | |
149 // This iterates of the data elements and segments the 'bytes' data into | |
150 // the smallest number of segments given the max_segment_size. | |
151 // The callback describes either: | |
152 // * A non-memory item | |
153 // * A partition of a bytes element which will be populated into a given | |
154 // segment and segment offset. | |
155 // More specifically, we split each |element| into one or more |segments| of a | |
156 // max_size, invokes the strategy to determine the request to make for each | |
157 // |segment| produced. A |segment| can also span multiple |elements|. | |
158 // Assumptions: All memory items are consolidated. As in, there are no two | |
159 // 'bytes' items next to eachother. | |
160 template <typename Visitor> | |
161 void ForEachWithSegment(const std::vector<DataElement>& elements, | |
162 uint64_t max_segment_size, | |
163 Visitor* visitor) { | |
164 DCHECK_GT(max_segment_size, 0ull); | |
165 size_t segment_index = 0; | |
166 uint64_t segment_offset = 0; | |
167 size_t elements_length = elements.size(); | |
168 for (size_t element_index = 0; element_index < elements_length; | |
169 ++element_index) { | |
170 const auto& element = elements.at(element_index); | |
171 DataElement::Type type = element.type(); | |
172 if (!IsBytes(type)) { | |
173 visitor->VisitNonBytesSegment(element, element_index); | |
174 continue; | |
175 } | |
176 uint64_t element_memory_left = element.length(); | |
177 uint64_t element_offset = 0; | |
178 while (element_memory_left > 0) { | |
179 if (segment_offset == max_segment_size) { | |
180 ++segment_index; | |
181 segment_offset = 0; | |
182 } | |
183 uint64_t memory_writing = | |
184 std::min(max_segment_size - segment_offset, element_memory_left); | |
185 visitor->VisitBytesSegment(element_index, element_offset, segment_index, | |
186 segment_offset, memory_writing); | |
187 element_memory_left -= memory_writing; | |
188 segment_offset += memory_writing; | |
189 element_offset += memory_writing; | |
190 } | |
191 } | |
192 visitor->Done(); | |
193 } | |
194 } // namespace | |
195 | |
196 BlobAsyncTransportRequestBuilder::RendererMemoryItemRequest:: | |
197 RendererMemoryItemRequest() | |
198 : browser_item_index(0), browser_item_offset(0) {} | |
199 | |
200 BlobAsyncTransportRequestBuilder::BlobAsyncTransportRequestBuilder() | |
201 : total_bytes_size_(0) {} | |
202 | |
203 BlobAsyncTransportRequestBuilder::~BlobAsyncTransportRequestBuilder() {} | |
204 | |
205 // Initializes the transport strategy for file requests. | |
206 void BlobAsyncTransportRequestBuilder::InitializeForFileRequests( | |
207 size_t max_file_size, | |
208 uint64_t blob_total_size, | |
209 const std::vector<DataElement>& elements, | |
210 BlobDataBuilder* builder) { | |
211 DCHECK(requests_.empty()); | |
212 total_bytes_size_ = blob_total_size; | |
213 ComputeHandleSizes(total_bytes_size_, max_file_size, &file_sizes_); | |
214 FileStorageStrategy strategy(&requests_, builder); | |
215 ForEachWithSegment(elements, static_cast<uint64_t>(max_file_size), &strategy); | |
216 } | |
217 | |
218 void BlobAsyncTransportRequestBuilder::InitializeForSharedMemoryRequests( | |
219 size_t max_shared_memory_size, | |
220 uint64_t blob_total_size, | |
221 const std::vector<DataElement>& elements, | |
222 BlobDataBuilder* builder) { | |
223 DCHECK(requests_.empty()); | |
224 DCHECK(blob_total_size <= std::numeric_limits<size_t>::max()); | |
225 total_bytes_size_ = blob_total_size; | |
226 ComputeHandleSizes(total_bytes_size_, max_shared_memory_size, | |
227 &shared_memory_sizes_); | |
228 SharedMemoryStorageStrategy strategy(max_shared_memory_size, &requests_, | |
229 builder); | |
230 ForEachWithSegment(elements, static_cast<uint64_t>(max_shared_memory_size), | |
231 &strategy); | |
232 } | |
233 | |
234 void BlobAsyncTransportRequestBuilder::InitializeForIPCRequests( | |
235 size_t max_ipc_memory_size, | |
236 uint64_t blob_total_size, | |
237 const std::vector<DataElement>& elements, | |
238 BlobDataBuilder* builder) { | |
239 DCHECK(requests_.empty()); | |
240 // We don't segment anything, and just request the memory items directly | |
241 // in IPC. | |
242 size_t items_length = elements.size(); | |
243 total_bytes_size_ = blob_total_size; | |
244 for (size_t i = 0; i < items_length; i++) { | |
245 const auto& info = elements.at(i); | |
246 if (!IsBytes(info.type())) { | |
247 builder->AppendIPCDataElement(info); | |
248 continue; | |
249 } | |
250 BlobAsyncTransportRequestBuilder::RendererMemoryItemRequest request; | |
251 request.browser_item_index = i; | |
252 request.browser_item_offset = 0; | |
253 request.message.request_number = requests_.size(); | |
254 request.message.transport_strategy = IPCBlobItemRequestStrategy::IPC; | |
255 request.message.renderer_item_index = i; | |
256 request.message.renderer_item_offset = 0; | |
257 request.message.size = info.length(); | |
258 requests_.push_back(request); | |
259 builder->AppendFutureData(info.length()); | |
260 } | |
261 } | |
262 | |
263 /* static */ | |
264 bool BlobAsyncTransportRequestBuilder::ShouldBeShortcut( | |
265 const std::vector<DataElement>& elements, | |
266 size_t memory_available) { | |
267 base::CheckedNumeric<size_t> shortcut_bytes = 0; | |
268 for (const auto& element : elements) { | |
269 DataElement::Type type = element.type(); | |
270 if (type == DataElement::TYPE_BYTES_DESCRIPTION) { | |
271 return false; | |
272 } | |
273 if (type == DataElement::TYPE_BYTES) { | |
274 shortcut_bytes += element.length(); | |
275 if (!shortcut_bytes.IsValid()) { | |
276 return false; | |
277 } | |
278 } | |
279 } | |
280 return shortcut_bytes.ValueOrDie() <= memory_available; | |
281 } | |
282 | |
283 /* static */ | |
284 void BlobAsyncTransportRequestBuilder::ComputeHandleSizes( | |
285 uint64_t total_memory_size, | |
286 size_t max_segment_size, | |
287 std::vector<size_t>* segment_sizes) { | |
288 size_t total_max_segments = | |
289 static_cast<size_t>(total_memory_size / max_segment_size); | |
290 bool has_extra_segment = (total_memory_size % max_segment_size) > 0; | |
291 segment_sizes->reserve(total_max_segments + (has_extra_segment ? 1 : 0)); | |
292 segment_sizes->insert(segment_sizes->begin(), total_max_segments, | |
293 max_segment_size); | |
294 if (has_extra_segment) { | |
295 segment_sizes->push_back(total_memory_size % max_segment_size); | |
296 } | |
297 } | |
298 | |
299 } // namespace storage | |
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