NuCachedSource2.cpp revision 6ee94582e3ce7bdd9625345e7564e3176a51a2f3 
1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#define LOG_TAG "NuCachedSource2"
18#include <utils/Log.h>
19
20#include "include/NuCachedSource2.h"
21
22#include <media/stagefright/foundation/ADebug.h>
23#include <media/stagefright/foundation/AMessage.h>
24#include <media/stagefright/MediaErrors.h>
25
26namespace android {
27
28struct PageCache {
29    PageCache(size_t pageSize);
30    ~PageCache();
31
32    struct Page {
33        void *mData;
34        size_t mSize;
35    };
36
37    Page *acquirePage();
38    void releasePage(Page *page);
39
40    void appendPage(Page *page);
41    size_t releaseFromStart(size_t maxBytes);
42
43    size_t totalSize() const {
44        return mTotalSize;
45    }
46
47    void copy(size_t from, void *data, size_t size);
48
49private:
50    size_t mPageSize;
51    size_t mTotalSize;
52
53    List<Page *> mActivePages;
54    List<Page *> mFreePages;
55
56    void freePages(List<Page *> *list);
57
58    DISALLOW_EVIL_CONSTRUCTORS(PageCache);
59};
60
61PageCache::PageCache(size_t pageSize)
62    : mPageSize(pageSize),
63      mTotalSize(0) {
64}
65
66PageCache::~PageCache() {
67    freePages(&mActivePages);
68    freePages(&mFreePages);
69}
70
71void PageCache::freePages(List<Page *> *list) {
72    List<Page *>::iterator it = list->begin();
73    while (it != list->end()) {
74        Page *page = *it;
75
76        free(page->mData);
77        delete page;
78        page = NULL;
79
80        ++it;
81    }
82}
83
84PageCache::Page *PageCache::acquirePage() {
85    if (!mFreePages.empty()) {
86        List<Page *>::iterator it = mFreePages.begin();
87        Page *page = *it;
88        mFreePages.erase(it);
89
90        return page;
91    }
92
93    Page *page = new Page;
94    page->mData = malloc(mPageSize);
95    page->mSize = 0;
96
97    return page;
98}
99
100void PageCache::releasePage(Page *page) {
101    page->mSize = 0;
102    mFreePages.push_back(page);
103}
104
105void PageCache::appendPage(Page *page) {
106    mTotalSize += page->mSize;
107    mActivePages.push_back(page);
108}
109
110size_t PageCache::releaseFromStart(size_t maxBytes) {
111    size_t bytesReleased = 0;
112
113    while (maxBytes > 0 && !mActivePages.empty()) {
114        List<Page *>::iterator it = mActivePages.begin();
115
116        Page *page = *it;
117
118        if (maxBytes < page->mSize) {
119            break;
120        }
121
122        mActivePages.erase(it);
123
124        maxBytes -= page->mSize;
125        bytesReleased += page->mSize;
126
127        releasePage(page);
128    }
129
130    mTotalSize -= bytesReleased;
131    return bytesReleased;
132}
133
134void PageCache::copy(size_t from, void *data, size_t size) {
135    LOGV("copy from %d size %d", from, size);
136
137    CHECK_LE(from + size, mTotalSize);
138
139    size_t offset = 0;
140    List<Page *>::iterator it = mActivePages.begin();
141    while (from >= offset + (*it)->mSize) {
142        offset += (*it)->mSize;
143        ++it;
144    }
145
146    size_t delta = from - offset;
147    size_t avail = (*it)->mSize - delta;
148
149    if (avail >= size) {
150        memcpy(data, (const uint8_t *)(*it)->mData + delta, size);
151        return;
152    }
153
154    memcpy(data, (const uint8_t *)(*it)->mData + delta, avail);
155    ++it;
156    data = (uint8_t *)data + avail;
157    size -= avail;
158
159    while (size > 0) {
160        size_t copy = (*it)->mSize;
161        if (copy > size) {
162            copy = size;
163        }
164        memcpy(data, (*it)->mData, copy);
165        data = (uint8_t *)data + copy;
166        size -= copy;
167        ++it;
168    }
169}
170
171////////////////////////////////////////////////////////////////////////////////
172
173NuCachedSource2::NuCachedSource2(const sp<DataSource> &source)
174    : mSource(source),
175      mReflector(new AHandlerReflector<NuCachedSource2>(this)),
176      mLooper(new ALooper),
177      mCache(new PageCache(kPageSize)),
178      mCacheOffset(0),
179      mFinalStatus(OK),
180      mLastAccessPos(0),
181      mFetching(true),
182      mLastFetchTimeUs(-1) {
183    mLooper->setName("NuCachedSource2");
184    mLooper->registerHandler(mReflector);
185    mLooper->start();
186
187    Mutex::Autolock autoLock(mLock);
188    (new AMessage(kWhatFetchMore, mReflector->id()))->post();
189}
190
191NuCachedSource2::~NuCachedSource2() {
192    mLooper->stop();
193    mLooper->unregisterHandler(mReflector->id());
194
195    delete mCache;
196    mCache = NULL;
197}
198
199status_t NuCachedSource2::initCheck() const {
200    return mSource->initCheck();
201}
202
203status_t NuCachedSource2::getSize(off64_t *size) {
204    return mSource->getSize(size);
205}
206
207uint32_t NuCachedSource2::flags() {
208    return (mSource->flags() & ~kWantsPrefetching) | kIsCachingDataSource;
209}
210
211void NuCachedSource2::onMessageReceived(const sp<AMessage> &msg) {
212    switch (msg->what()) {
213        case kWhatFetchMore:
214        {
215            onFetch();
216            break;
217        }
218
219        case kWhatRead:
220        {
221            onRead(msg);
222            break;
223        }
224
225        default:
226            TRESPASS();
227    }
228}
229
230void NuCachedSource2::fetchInternal() {
231    LOGV("fetchInternal");
232
233    CHECK_EQ(mFinalStatus, (status_t)OK);
234
235    PageCache::Page *page = mCache->acquirePage();
236
237    ssize_t n = mSource->readAt(
238            mCacheOffset + mCache->totalSize(), page->mData, kPageSize);
239
240    Mutex::Autolock autoLock(mLock);
241
242    if (n < 0) {
243        LOGE("source returned error %ld", n);
244        mFinalStatus = n;
245        mCache->releasePage(page);
246    } else if (n == 0) {
247        LOGI("ERROR_END_OF_STREAM");
248        mFinalStatus = ERROR_END_OF_STREAM;
249        mCache->releasePage(page);
250    } else {
251        page->mSize = n;
252        mCache->appendPage(page);
253    }
254}
255
256void NuCachedSource2::onFetch() {
257    LOGV("onFetch");
258
259    if (mFinalStatus != OK) {
260        LOGV("EOS reached, done prefetching for now");
261        mFetching = false;
262    }
263
264    bool keepAlive =
265        !mFetching
266            && mFinalStatus == OK
267            && ALooper::GetNowUs() >= mLastFetchTimeUs + kKeepAliveIntervalUs;
268
269    if (mFetching || keepAlive) {
270        if (keepAlive) {
271            LOGI("Keep alive");
272        }
273
274        fetchInternal();
275
276        mLastFetchTimeUs = ALooper::GetNowUs();
277
278        if (mFetching && mCache->totalSize() >= kHighWaterThreshold) {
279            LOGI("Cache full, done prefetching for now");
280            mFetching = false;
281        }
282    } else {
283        Mutex::Autolock autoLock(mLock);
284        restartPrefetcherIfNecessary_l();
285    }
286
287    (new AMessage(kWhatFetchMore, mReflector->id()))->post(
288            mFetching ? 0 : 100000ll);
289}
290
291void NuCachedSource2::onRead(const sp<AMessage> &msg) {
292    LOGV("onRead");
293
294    int64_t offset;
295    CHECK(msg->findInt64("offset", &offset));
296
297    void *data;
298    CHECK(msg->findPointer("data", &data));
299
300    size_t size;
301    CHECK(msg->findSize("size", &size));
302
303    ssize_t result = readInternal(offset, data, size);
304
305    if (result == -EAGAIN) {
306        msg->post(50000);
307        return;
308    }
309
310    Mutex::Autolock autoLock(mLock);
311
312    CHECK(mAsyncResult == NULL);
313
314    mAsyncResult = new AMessage;
315    mAsyncResult->setInt32("result", result);
316
317    mCondition.signal();
318}
319
320void NuCachedSource2::restartPrefetcherIfNecessary_l(
321        bool ignoreLowWaterThreshold) {
322    static const size_t kGrayArea = 1024 * 1024;
323
324    if (mFetching || mFinalStatus != OK) {
325        return;
326    }
327
328    if (!ignoreLowWaterThreshold
329            && mCacheOffset + mCache->totalSize() - mLastAccessPos
330                >= kLowWaterThreshold) {
331        return;
332    }
333
334    size_t maxBytes = mLastAccessPos - mCacheOffset;
335    if (maxBytes < kGrayArea) {
336        return;
337    }
338
339    maxBytes -= kGrayArea;
340
341    size_t actualBytes = mCache->releaseFromStart(maxBytes);
342    mCacheOffset += actualBytes;
343
344    LOGI("restarting prefetcher, totalSize = %d", mCache->totalSize());
345    mFetching = true;
346}
347
348ssize_t NuCachedSource2::readAt(off64_t offset, void *data, size_t size) {
349    Mutex::Autolock autoSerializer(mSerializer);
350
351    LOGV("readAt offset %lld, size %d", offset, size);
352
353    Mutex::Autolock autoLock(mLock);
354
355    // If the request can be completely satisfied from the cache, do so.
356
357    if (offset >= mCacheOffset
358            && offset + size <= mCacheOffset + mCache->totalSize()) {
359        size_t delta = offset - mCacheOffset;
360        mCache->copy(delta, data, size);
361
362        mLastAccessPos = offset + size;
363
364        return size;
365    }
366
367    sp<AMessage> msg = new AMessage(kWhatRead, mReflector->id());
368    msg->setInt64("offset", offset);
369    msg->setPointer("data", data);
370    msg->setSize("size", size);
371
372    CHECK(mAsyncResult == NULL);
373    msg->post();
374
375    while (mAsyncResult == NULL) {
376        mCondition.wait(mLock);
377    }
378
379    int32_t result;
380    CHECK(mAsyncResult->findInt32("result", &result));
381
382    mAsyncResult.clear();
383
384    if (result > 0) {
385        mLastAccessPos = offset + result;
386    }
387
388    return (ssize_t)result;
389}
390
391size_t NuCachedSource2::cachedSize() {
392    Mutex::Autolock autoLock(mLock);
393    return mCacheOffset + mCache->totalSize();
394}
395
396size_t NuCachedSource2::approxDataRemaining(bool *eos) {
397    Mutex::Autolock autoLock(mLock);
398    return approxDataRemaining_l(eos);
399}
400
401size_t NuCachedSource2::approxDataRemaining_l(bool *eos) {
402    *eos = (mFinalStatus != OK);
403    off64_t lastBytePosCached = mCacheOffset + mCache->totalSize();
404    if (mLastAccessPos < lastBytePosCached) {
405        return lastBytePosCached - mLastAccessPos;
406    }
407    return 0;
408}
409
410ssize_t NuCachedSource2::readInternal(off64_t offset, void *data, size_t size) {
411    LOGV("readInternal offset %lld size %d", offset, size);
412
413    Mutex::Autolock autoLock(mLock);
414
415    if (offset < mCacheOffset
416            || offset >= (off64_t)(mCacheOffset + mCache->totalSize())) {
417        static const off64_t kPadding = 256 * 1024;
418
419        // In the presence of multiple decoded streams, once of them will
420        // trigger this seek request, the other one will request data "nearby"
421        // soon, adjust the seek position so that that subsequent request
422        // does not trigger another seek.
423        off64_t seekOffset = (offset > kPadding) ? offset - kPadding : 0;
424
425        seekInternal_l(seekOffset);
426    }
427
428    size_t delta = offset - mCacheOffset;
429
430    if (mFinalStatus != OK) {
431        if (delta >= mCache->totalSize()) {
432            return mFinalStatus;
433        }
434
435        size_t avail = mCache->totalSize() - delta;
436        mCache->copy(delta, data, avail);
437
438        return avail;
439    }
440
441    if (offset + size <= mCacheOffset + mCache->totalSize()) {
442        mCache->copy(delta, data, size);
443
444        return size;
445    }
446
447    LOGV("deferring read");
448
449    return -EAGAIN;
450}
451
452status_t NuCachedSource2::seekInternal_l(off64_t offset) {
453    mLastAccessPos = offset;
454
455    if (offset >= mCacheOffset
456            && offset <= (off64_t)(mCacheOffset + mCache->totalSize())) {
457        return OK;
458    }
459
460    LOGI("new range: offset= %lld", offset);
461
462    mCacheOffset = offset;
463
464    size_t totalSize = mCache->totalSize();
465    CHECK_EQ(mCache->releaseFromStart(totalSize), totalSize);
466
467    mFinalStatus = OK;
468    mFetching = true;
469
470    return OK;
471}
472
473void NuCachedSource2::resumeFetchingIfNecessary() {
474    Mutex::Autolock autoLock(mLock);
475
476    restartPrefetcherIfNecessary_l(true /* ignore low water threshold */);
477}
478
479DecryptHandle* NuCachedSource2::DrmInitialization(DrmManagerClient* client) {
480    return mSource->DrmInitialization(client);
481}
482
483void NuCachedSource2::getDrmInfo(DecryptHandle **handle, DrmManagerClient **client) {
484    mSource->getDrmInfo(handle, client);
485}
486
487String8 NuCachedSource2::getUri() {
488    return mSource->getUri();
489}
490}  // namespace android
491
492