media/libstagefright/HTTPDataSource.cpp

/*
 * Copyright (C) 2009 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#undef NDEBUG
#include <assert.h>

#include <stdlib.h>

#include <media/stagefright/HTTPDataSource.h>
#include <media/stagefright/HTTPStream.h>
#include <media/stagefright/string.h>

namespace android {

HTTPDataSource::HTTPDataSource(const char *uri)
    : mHost(NULL),
      mPort(0),
      mPath(NULL),
      mBuffer(malloc(kBufferSize)),
      mBufferLength(0),
      mBufferOffset(0) {
    assert(!strncasecmp("http://", uri, 7));

    string host;
    string path;
    int port;

    char *slash = strchr(uri + 7, '/');
    if (slash == NULL) {
        host = uri + 7;
        path = "/";
    } else {
        host = string(uri + 7, slash - (uri + 7));
        path = slash;
    }

    char *colon = strchr(host.c_str(), ':');
    if (colon == NULL) {
        port = 80;
    } else {
        char *end;
        long tmp = strtol(colon + 1, &end, 10);
        assert(end > colon + 1);
        assert(tmp > 0 && tmp < 65536);
        port = tmp;

        host = string(host, 0, colon - host.c_str());
    }

    LOGI("Connecting to host '%s', port %d, path '%s'",
         host.c_str(), port, path.c_str());

    mHost = strdup(host.c_str());
    mPort = port;
    mPath = strdup(path.c_str());

    status_t err = mHttp.connect(mHost, mPort);
    assert(err == OK);
}

HTTPDataSource::HTTPDataSource(const char *host, int port, const char *path)
    : mHost(strdup(host)),
      mPort(port),
      mPath(strdup(path)),
      mBuffer(malloc(kBufferSize)),
      mBufferLength(0),
      mBufferOffset(0) {
    status_t err = mHttp.connect(mHost, mPort);
    assert(err == OK);
}

HTTPDataSource::~HTTPDataSource() {
    mHttp.disconnect();

    free(mBuffer);
    mBuffer = NULL;

    free(mPath);
    mPath = NULL;
}

ssize_t HTTPDataSource::read_at(off_t offset, void *data, size_t size) {
    if (offset >= mBufferOffset && offset < mBufferOffset + mBufferLength) {
        size_t num_bytes_available = mBufferLength - (offset - mBufferOffset);

        size_t copy = num_bytes_available;
        if (copy > size) {
            copy = size;
        }

        memcpy(data, (const char *)mBuffer + (offset - mBufferOffset), copy);

        return copy;
    }

    mBufferOffset = offset;
    mBufferLength = 0;

    char host[128];
    sprintf(host, "Host: %s\r\n", mHost);

    char range[128];
    sprintf(range, "Range: bytes=%ld-%ld\r\n\r\n",
            mBufferOffset, mBufferOffset + kBufferSize - 1);

    int http_status;

    status_t err;
    int attempt = 1;
    for (;;) {
        if ((err = mHttp.send("GET ")) != OK
            || (err = mHttp.send(mPath)) != OK
            || (err = mHttp.send(" HTTP/1.1\r\n")) != OK
            || (err = mHttp.send(host)) != OK
            || (err = mHttp.send(range)) != OK
            || (err = mHttp.send("\r\n")) != OK
            || (err = mHttp.receive_header(&http_status)) != OK) {

            if (attempt == 3) {
                return err;
            }

            mHttp.connect(mHost, mPort);
            ++attempt;
        } else {
            break;
        }
    }

    if ((http_status / 100) != 2) {
        return UNKNOWN_ERROR;
    }

    string value;
    if (!mHttp.find_header_value("Content-Length", &value)) {
        return UNKNOWN_ERROR;
    }

    char *end;
    unsigned long contentLength = strtoul(value.c_str(), &end, 10);

    ssize_t num_bytes_received = mHttp.receive(mBuffer, contentLength);

    if (num_bytes_received <= 0) {
        return num_bytes_received;
    }

    mBufferLength = (size_t)num_bytes_received;

    size_t copy = mBufferLength;
    if (copy > size) {
        copy = size;
    }

    memcpy(data, mBuffer, copy);

    return copy;
}

}  // namespace android