3 #include <netinet/in.h>
13 #include "metacube2.h"
14 #include "mutexlock.h"
21 Stream::Stream(const string &url, size_t backlog_size, Encoding encoding)
24 data_fd(make_tempfile("")),
25 backlog_size(backlog_size),
27 last_suitable_starting_point(-1),
30 queued_data_last_starting_point(-1)
36 pthread_mutex_init(&queued_data_mutex, NULL);
46 Stream::Stream(const StreamProto &serialized, int data_fd)
47 : url(serialized.url()),
48 http_header(serialized.http_header()),
49 stream_header(serialized.stream_header()),
50 encoding(Stream::STREAM_ENCODING_RAW), // Will be changed later.
52 backlog_size(serialized.backlog_size()),
53 bytes_received(serialized.bytes_received()),
56 queued_data_last_starting_point(-1)
62 assert(serialized.has_last_suitable_starting_point());
63 last_suitable_starting_point = serialized.last_suitable_starting_point();
65 pthread_mutex_init(&queued_data_mutex, NULL);
68 StreamProto Stream::serialize()
70 StreamProto serialized;
71 serialized.set_http_header(http_header);
72 serialized.set_stream_header(stream_header);
73 serialized.add_data_fds(data_fd);
74 serialized.set_backlog_size(backlog_size);
75 serialized.set_bytes_received(bytes_received);
76 serialized.set_last_suitable_starting_point(last_suitable_starting_point);
77 serialized.set_url(url);
82 void Stream::set_backlog_size(size_t new_size)
84 if (backlog_size == new_size) {
89 if (!read_tempfile_and_close(data_fd, &existing_data)) {
93 // Unwrap the data so it's no longer circular.
94 if (bytes_received <= backlog_size) {
95 existing_data.resize(bytes_received);
97 size_t pos = bytes_received % backlog_size;
98 existing_data = existing_data.substr(pos, string::npos) +
99 existing_data.substr(0, pos);
102 // See if we need to discard data.
103 if (new_size < existing_data.size()) {
104 size_t to_discard = existing_data.size() - new_size;
105 existing_data = existing_data.substr(to_discard, string::npos);
108 // Create a new, empty data file.
109 data_fd = make_tempfile("");
113 backlog_size = new_size;
115 // Now cheat a bit by rewinding, and adding all the old data back.
116 bytes_received -= existing_data.size();
118 iov.iov_base = const_cast<char *>(existing_data.data());
119 iov.iov_len = existing_data.size();
126 void Stream::put_client_to_sleep(Client *client)
128 sleeping_clients.push_back(client);
131 // Return a new set of iovecs that contains only the first <bytes_wanted> bytes of <data>.
132 vector<iovec> collect_iovecs(const vector<iovec> &data, size_t bytes_wanted)
135 size_t max_iovecs = std::min<size_t>(data.size(), IOV_MAX);
136 for (size_t i = 0; i < max_iovecs && bytes_wanted > 0; ++i) {
137 if (data[i].iov_len <= bytes_wanted) {
138 // Consume the entire iovec.
139 ret.push_back(data[i]);
140 bytes_wanted -= data[i].iov_len;
142 // Take only parts of this iovec.
144 iov.iov_base = data[i].iov_base;
145 iov.iov_len = bytes_wanted;
153 // Return a new set of iovecs that contains all of <data> except the first <bytes_wanted> bytes.
154 vector<iovec> remove_iovecs(const vector<iovec> &data, size_t bytes_wanted)
158 for (i = 0; i < data.size() && bytes_wanted > 0; ++i) {
159 if (data[i].iov_len <= bytes_wanted) {
160 // Consume the entire iovec.
161 bytes_wanted -= data[i].iov_len;
163 // Take only parts of this iovec.
165 iov.iov_base = reinterpret_cast<char *>(data[i].iov_base) + bytes_wanted;
166 iov.iov_len = data[i].iov_len - bytes_wanted;
172 // Add the rest of the iovecs unchanged.
173 ret.insert(ret.end(), data.begin() + i, data.end());
177 void Stream::add_data_raw(const vector<iovec> &orig_data)
179 vector<iovec> data = orig_data;
180 while (!data.empty()) {
181 size_t pos = bytes_received % backlog_size;
183 // Collect as many iovecs as we can before we hit the point
184 // where the circular buffer wraps around.
185 vector<iovec> to_write = collect_iovecs(data, backlog_size - pos);
188 ret = pwritev(data_fd, to_write.data(), to_write.size(), pos);
189 } while (ret == -1 && errno == EINTR);
192 log_perror("pwritev");
193 // Dazed and confused, but trying to continue...
196 bytes_received += ret;
198 // Remove the data that was actually written from the set of iovecs.
199 data = remove_iovecs(data, ret);
203 void Stream::add_data_deferred(const char *data, size_t bytes, StreamStartSuitability suitable_for_stream_start)
205 MutexLock lock(&queued_data_mutex);
206 assert(suitable_for_stream_start == SUITABLE_FOR_STREAM_START ||
207 suitable_for_stream_start == NOT_SUITABLE_FOR_STREAM_START);
208 if (suitable_for_stream_start == SUITABLE_FOR_STREAM_START) {
209 queued_data_last_starting_point = queued_data.size();
212 if (encoding == Stream::STREAM_ENCODING_METACUBE) {
213 // Add a Metacube block header before the data.
214 metacube2_block_header hdr;
215 memcpy(hdr.sync, METACUBE2_SYNC, sizeof(hdr.sync));
216 hdr.size = htonl(bytes);
217 hdr.flags = htons(0);
218 if (suitable_for_stream_start == NOT_SUITABLE_FOR_STREAM_START) {
219 hdr.flags |= htons(METACUBE_FLAGS_NOT_SUITABLE_FOR_STREAM_START);
221 hdr.csum = htons(metacube2_compute_crc(&hdr));
224 iov.iov_base = new char[bytes + sizeof(hdr)];
225 iov.iov_len = bytes + sizeof(hdr);
227 memcpy(iov.iov_base, &hdr, sizeof(hdr));
228 memcpy(reinterpret_cast<char *>(iov.iov_base) + sizeof(hdr), data, bytes);
230 queued_data.push_back(iov);
231 } else if (encoding == Stream::STREAM_ENCODING_RAW) {
232 // Just add the data itself.
234 iov.iov_base = new char[bytes];
235 memcpy(iov.iov_base, data, bytes);
238 queued_data.push_back(iov);
244 void Stream::process_queued_data()
246 std::vector<iovec> queued_data_copy;
247 int queued_data_last_starting_point_copy = -1;
249 // Hold the lock for as short as possible, since add_data_raw() can possibly
250 // write to disk, which might disturb the input thread.
252 MutexLock lock(&queued_data_mutex);
253 if (queued_data.empty()) {
257 swap(queued_data, queued_data_copy);
258 swap(queued_data_last_starting_point, queued_data_last_starting_point_copy);
261 // Update the last suitable starting point for the stream,
262 // if the queued data contains such a starting point.
263 assert(queued_data_last_starting_point_copy < ssize_t(queued_data_copy.size()));
264 if (queued_data_last_starting_point_copy >= 0) {
265 last_suitable_starting_point = bytes_received;
266 for (int i = 0; i < queued_data_last_starting_point_copy; ++i) {
267 last_suitable_starting_point += queued_data_copy[i].iov_len;
271 add_data_raw(queued_data_copy);
272 for (size_t i = 0; i < queued_data_copy.size(); ++i) {
273 char *data = reinterpret_cast<char *>(queued_data_copy[i].iov_base);
277 // We have more data, so wake up all clients.
278 if (to_process.empty()) {
279 swap(sleeping_clients, to_process);
281 to_process.insert(to_process.end(), sleeping_clients.begin(), sleeping_clients.end());
282 sleeping_clients.clear();