C++ FileMap::release方法代码示例

FileMap*
FileMapBuffer::createMap(const char* filename)
{
	int fd;
	size_t length;

	fd = ::open(filename, O_RDONLY | O_BINARY);
	if (fd < 0) {
		LOGW("Unable to open file '%s': %s\n", filename, strerror(errno));
		return NULL;
	}

	length = lseek(fd, 0, SEEK_END);
	lseek(fd, 0, SEEK_SET);

	FileMap* map = new FileMap();
	if (!map) {
		LOGW("Unable to create file map for '%s': %s\n", filename, strerror(errno));
		return NULL;
	}

	if (!map->create(filename, fd, 0, length, true)) {
		map->release();
		LOGW("Unable to create file map for '%s': %s\n", filename, strerror(errno));
		return NULL;
	}

	close(fd);

	return map;
}

status_t Tokenizer::open(const String8& filename, Tokenizer** outTokenizer) {
    *outTokenizer = NULL;

    int result = NO_ERROR;
    int fd = ::open(filename.string(), O_RDONLY);
    if (fd < 0) {
        result = -errno;
        LOGE("Error opening file '%s', %s.", filename.string(), strerror(errno));
    } else {
        struct stat stat;
        if (fstat(fd, &stat)) {
            result = -errno;
            LOGE("Error getting size of file '%s', %s.", filename.string(), strerror(errno));
        } else {
            size_t length = size_t(stat.st_size);

            FileMap* fileMap = new FileMap();
            char* buffer;
            if (fileMap->create(NULL, fd, 0, length, true)) {
                fileMap->advise(FileMap::SEQUENTIAL);
                buffer = static_cast<char*>(fileMap->getDataPtr());
            } else {
                fileMap->release();
                fileMap = NULL;

                // Fall back to reading into a buffer since we can't mmap files in sysfs.
                // The length we obtained from stat is wrong too (it will always be 4096)
                // so we must trust that read will read the entire file.
                buffer = new char[length];
                ssize_t nrd = read(fd, buffer, length);
                if (nrd < 0) {
                    result = -errno;
                    LOGE("Error reading file '%s', %s.", filename.string(), strerror(errno));
                    delete[] buffer;
                    buffer = NULL;
                } else {
                    length = size_t(nrd);
                }
            }

            if (!result) {
                *outTokenizer = new Tokenizer(filename, fileMap, buffer, length);
            }
        }
        close(fd);
    }
    return result;
}

bool BootAnimation::readFile(const char* name, String8& outString)
{
    ZipEntryRO entry = mZip->findEntryByName(name);
    ALOGE_IF(!entry, "couldn't find %s", name);
    if (!entry) {
        return false;
    }

    FileMap* entryMap = mZip->createEntryFileMap(entry);
    mZip->releaseEntry(entry);
    ALOGE_IF(!entryMap, "entryMap is null");
    if (!entryMap) {
        return false;
    }

    outString.setTo((char const*)entryMap->getDataPtr(), entryMap->getDataLength());
    entryMap->release();
    return true;
}

/*
 * Create a new FileMap object that spans the data in "entry".
 */
FileMap* ZipFileRO::createEntryFileMap(ZipEntryRO entry) const
{
    const _ZipEntryRO *zipEntry = reinterpret_cast<_ZipEntryRO*>(entry);
    const ZipEntry& ze = zipEntry->entry;
    int fd = GetFileDescriptor(mHandle);
    size_t actualLen = 0;

    if (ze.method == kCompressStored) {
        actualLen = ze.uncompressed_length;
    } else {
        actualLen = ze.compressed_length;
    }

    FileMap* newMap = new FileMap();
    if (!newMap->create(mFileName, fd, ze.offset, actualLen, true)) {
        newMap->release();
        return NULL;
    }

    return newMap;
}

bool BootAnimation::movie()
{
    ZipEntryRO desc = mZip->findEntryByName("desc.txt");
    ALOGE_IF(!desc, "couldn't find desc.txt");
    if (!desc) {
        return false;
    }

    FileMap* descMap = mZip->createEntryFileMap(desc);
    mZip->releaseEntry(desc);
    ALOGE_IF(!descMap, "descMap is null");
    if (!descMap) {
        return false;
    }

    String8 desString((char const*)descMap->getDataPtr(),
            descMap->getDataLength());
    descMap->release();
    char const* s = desString.string();

    Animation animation;

    // Parse the description file
    for (;;) {
        const char* endl = strstr(s, "\n");
        if (!endl) break;
        String8 line(s, endl - s);
        const char* l = line.string();
        int fps, width, height, count, pause;
        char path[ANIM_ENTRY_NAME_MAX];
        char pathType;
        if (sscanf(l, "%d %d %d", &width, &height, &fps) == 3) {
            //LOGD("> w=%d, h=%d, fps=%d", width, height, fps);
            animation.width = width;
            animation.height = height;
            animation.fps = fps;
        }
        else if (sscanf(l, " %c %d %d %s", &pathType, &count, &pause, path) == 4) {
            //LOGD("> type=%c, count=%d, pause=%d, path=%s", pathType, count, pause, path);
            Animation::Part part;
            part.playUntilComplete = pathType == 'c';
            part.count = count;
            part.pause = pause;
            part.path = path;
            animation.parts.add(part);
        }

        s = ++endl;
    }

    // read all the data structures
    const size_t pcount = animation.parts.size();
    void *cookie = NULL;
    if (!mZip->startIteration(&cookie)) {
        return false;
    }

    ZipEntryRO entry;
    char name[ANIM_ENTRY_NAME_MAX];
    while ((entry = mZip->nextEntry(cookie)) != NULL) {
        const int foundEntryName = mZip->getEntryFileName(entry, name, ANIM_ENTRY_NAME_MAX);
        if (foundEntryName > ANIM_ENTRY_NAME_MAX || foundEntryName == -1) {
            ALOGE("Error fetching entry file name");
            continue;
        }

        const String8 entryName(name);
        const String8 path(entryName.getPathDir());
        const String8 leaf(entryName.getPathLeaf());
        if (leaf.size() > 0) {
            for (size_t j=0 ; j<pcount ; j++) {
                if (path == animation.parts[j].path) {
                    int method;
                    // supports only stored png files
                    if (mZip->getEntryInfo(entry, &method, NULL, NULL, NULL, NULL, NULL)) {
                        if (method == ZipFileRO::kCompressStored) {
                            FileMap* map = mZip->createEntryFileMap(entry);
                            if (map) {
                                Animation::Frame frame;
                                frame.name = leaf;
                                frame.map = map;
                                Animation::Part& part(animation.parts.editItemAt(j));
                                part.frames.add(frame);
                            }
                        }
                    }
                }
            }
        }
    }

    mZip->endIteration(cookie);

    // clear screen
    glShadeModel(GL_FLAT);
    glDisable(GL_DITHER);
    glDisable(GL_SCISSOR_TEST);
    glDisable(GL_BLEND);
    glClearColor(0,0,0,1);
    glClear(GL_COLOR_BUFFER_BIT);
//.........这里部分代码省略.........

/*
 * Return a read-only pointer to a buffer.
 *
 * We can either read the whole thing in or map the relevant piece of
 * the source file.  Ideally a map would be established at a higher
 * level and we'd be using a different object, but we didn't, so we
 * deal with it here.
 */
const void* _FileAsset::getBuffer(bool wordAligned)
{
    /* subsequent requests just use what we did previously */
    if (mBuf != NULL)
        return mBuf;
    if (mMap != NULL) {
        if (!wordAligned) {
            return  mMap->getDataPtr();
        }
        return ensureAlignment(mMap);
    }

    assert(mFp != NULL);

    if (mLength < kReadVsMapThreshold) {
        unsigned char* buf;
        long allocLen;

        /* zero-length files are allowed; not sure about zero-len allocs */
        /* (works fine with gcc + x86linux) */
        allocLen = mLength;
        if (mLength == 0)
            allocLen = 1;

        buf = new unsigned char[allocLen];
        if (buf == NULL) {
            LOGE("alloc of %ld bytes failed\n", (long) allocLen);
            return NULL;
        }

        LOGV("Asset %p allocating buffer size %d (smaller than threshold)", this, (int)allocLen);
        if (mLength > 0) {
            long oldPosn = ftell(mFp);
            fseek(mFp, mStart, SEEK_SET);
            if (fread(buf, 1, mLength, mFp) != (size_t) mLength) {
                LOGE("failed reading %ld bytes\n", (long) mLength);
                delete[] buf;
                return NULL;
            }
            fseek(mFp, oldPosn, SEEK_SET);
        }

        LOGV(" getBuffer: loaded into buffer\n");

        mBuf = buf;
        return mBuf;
    } else {
        FileMap* map;

        map = new FileMap;
        if (!map->create(NULL, fileno(mFp), mStart, mLength, true)) {
            map->release();
            return NULL;
        }

        LOGV(" getBuffer: mapped\n");

        mMap = map;
        if (!wordAligned) {
            return  mMap->getDataPtr();
        }
        return ensureAlignment(mMap);
    }
}