git.sesse.net Git - cubemap/blob - stream.cpp

   1 #include <assert.h>
   2 #include <errno.h>
   3 #include <netinet/in.h>
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <string.h>
   7 #include <sys/types.h>
   8 #include <algorithm>
   9 #include <string>
  10 #include <vector>
  11
  12 #include "log.h"
  13 #include "metacube2.h"
  14 #include "mutexlock.h"
  15 #include "state.pb.h"
  16 #include "stream.h"
  17 #include "util.h"
  18
  19 using namespace std;
  20
  21 Stream::Stream(const string &url, size_t backlog_size, Encoding encoding)
  22         : url(url),
  23           encoding(encoding),
  24           data_fd(make_tempfile("")),
  25           backlog_size(backlog_size),
  26           bytes_received(0),
  27           last_suitable_starting_point(-1),
  28           mark_pool(NULL),
  29           pacing_rate(~0U),
  30           queued_data_last_starting_point(-1)
  31 {
  32         if (data_fd == -1) {
  33                 exit(1);
  34         }
  35
  36         pthread_mutex_init(&queued_data_mutex, NULL);
  37 }
  38
  39 Stream::~Stream()
  40 {
  41         if (data_fd != -1) {
  42                 safe_close(data_fd);
  43         }
  44 }
  45
  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.
  51           data_fd(data_fd),
  52           backlog_size(serialized.backlog_size()),
  53           bytes_received(serialized.bytes_received()),
  54           mark_pool(NULL),
  55           pacing_rate(~0U),
  56           queued_data_last_starting_point(-1)
  57 {
  58         if (data_fd == -1) {
  59                 exit(1);
  60         }
  61
  62         // Split old-style headers into HTTP and video headers.
  63         if (!serialized.header().empty()) {
  64                 string header = serialized.header();
  65                 size_t split = header.find("\r\n\r\n");
  66                 if (split == string::npos) {
  67                         http_header = header;
  68                         stream_header = "";
  69                 } else {
  70                         http_header = header.substr(0, split + 2);  // Split off the second \r\n.
  71                         stream_header = header.substr(split, string::npos);
  72                 }
  73         }
  74
  75         // Older versions did not set last_suitable_starting_point.
  76         if (serialized.has_last_suitable_starting_point()) {
  77                 last_suitable_starting_point = serialized.last_suitable_starting_point();
  78         } else {
  79                 last_suitable_starting_point = bytes_received;
  80         }
  81
  82         pthread_mutex_init(&queued_data_mutex, NULL);
  83 }
  84
  85 StreamProto Stream::serialize()
  86 {
  87         StreamProto serialized;
  88         serialized.set_http_header(http_header);
  89         serialized.set_stream_header(stream_header);
  90         serialized.add_data_fds(data_fd);
  91         serialized.set_backlog_size(backlog_size);
  92         serialized.set_bytes_received(bytes_received);
  93         serialized.set_last_suitable_starting_point(last_suitable_starting_point);
  94         serialized.set_url(url);
  95         data_fd = -1;
  96         return serialized;
  97 }
  98
  99 void Stream::set_backlog_size(size_t new_size)
 100 {
 101         if (backlog_size == new_size) {
 102                 return;
 103         }
 104
 105         string existing_data;
 106         if (!read_tempfile_and_close(data_fd, &existing_data)) {
 107                 exit(1);
 108         }
 109
 110         // Unwrap the data so it's no longer circular.
 111         if (bytes_received <= backlog_size) {
 112                 existing_data.resize(bytes_received);
 113         } else {
 114                 size_t pos = bytes_received % backlog_size;
 115                 existing_data = existing_data.substr(pos, string::npos) +
 116                         existing_data.substr(0, pos);
 117         }
 118
 119         // See if we need to discard data.
 120         if (new_size < existing_data.size()) {
 121                 size_t to_discard = existing_data.size() - new_size;
 122                 existing_data = existing_data.substr(to_discard, string::npos);
 123         }
 124
 125         // Create a new, empty data file.
 126         data_fd = make_tempfile("");
 127         if (data_fd == -1) {
 128                 exit(1);
 129         }
 130         backlog_size = new_size;
 131
 132         // Now cheat a bit by rewinding, and adding all the old data back.
 133         bytes_received -= existing_data.size();
 134         iovec iov;
 135         iov.iov_base = const_cast<char *>(existing_data.data());
 136         iov.iov_len = existing_data.size();
 137
 138         vector<iovec> iovs;
 139         iovs.push_back(iov);
 140         add_data_raw(iovs);
 141 }
 142
 143 void Stream::put_client_to_sleep(Client *client)
 144 {
 145         sleeping_clients.push_back(client);
 146 }
 147
 148 // Return a new set of iovecs that contains only the first <bytes_wanted> bytes of <data>.
 149 vector<iovec> collect_iovecs(const vector<iovec> &data, size_t bytes_wanted)
 150 {
 151         vector<iovec> ret;
 152         size_t max_iovecs = std::min<size_t>(data.size(), IOV_MAX);
 153         for (size_t i = 0; i < max_iovecs && bytes_wanted > 0; ++i) {
 154                 if (data[i].iov_len <= bytes_wanted) {
 155                         // Consume the entire iovec.
 156                         ret.push_back(data[i]);
 157                         bytes_wanted -= data[i].iov_len;
 158                 } else {
 159                         // Take only parts of this iovec.
 160                         iovec iov;
 161                         iov.iov_base = data[i].iov_base;
 162                         iov.iov_len = bytes_wanted;
 163                         ret.push_back(iov);
 164                         bytes_wanted = 0;
 165                 }
 166         }
 167         return ret;
 168 }
 169
 170 // Return a new set of iovecs that contains all of <data> except the first <bytes_wanted> bytes.
 171 vector<iovec> remove_iovecs(const vector<iovec> &data, size_t bytes_wanted)
 172 {
 173         vector<iovec> ret;
 174         size_t i;
 175         for (i = 0; i < data.size() && bytes_wanted > 0; ++i) {
 176                 if (data[i].iov_len <= bytes_wanted) {
 177                         // Consume the entire iovec.
 178                         bytes_wanted -= data[i].iov_len;
 179                 } else {
 180                         // Take only parts of this iovec.
 181                         iovec iov;
 182                         iov.iov_base = reinterpret_cast<char *>(data[i].iov_base) + bytes_wanted;
 183                         iov.iov_len = data[i].iov_len - bytes_wanted;
 184                         ret.push_back(iov);
 185                         bytes_wanted = 0;
 186                 }
 187         }
 188
 189         // Add the rest of the iovecs unchanged.
 190         ret.insert(ret.end(), data.begin() + i, data.end());
 191         return ret;
 192 }
 193
 194 void Stream::add_data_raw(const vector<iovec> &orig_data)
 195 {
 196         vector<iovec> data = orig_data;
 197         while (!data.empty()) {
 198                 size_t pos = bytes_received % backlog_size;
 199
 200                 // Collect as many iovecs as we can before we hit the point
 201                 // where the circular buffer wraps around.
 202                 vector<iovec> to_write = collect_iovecs(data, backlog_size - pos);
 203                 ssize_t ret;
 204                 do {
 205                         ret = pwritev(data_fd, to_write.data(), to_write.size(), pos);
 206                 } while (ret == -1 && errno == EINTR);
 207
 208                 if (ret == -1) {
 209                         log_perror("pwritev");
 210                         // Dazed and confused, but trying to continue...
 211                         return;
 212                 }
 213                 bytes_received += ret;
 214
 215                 // Remove the data that was actually written from the set of iovecs.
 216                 data = remove_iovecs(data, ret);
 217         }
 218 }
 219
 220 void Stream::add_data_deferred(const char *data, size_t bytes, StreamStartSuitability suitable_for_stream_start)
 221 {
 222         MutexLock lock(&queued_data_mutex);
 223         assert(suitable_for_stream_start == SUITABLE_FOR_STREAM_START ||
 224                suitable_for_stream_start == NOT_SUITABLE_FOR_STREAM_START);
 225         if (suitable_for_stream_start == SUITABLE_FOR_STREAM_START) {
 226                 queued_data_last_starting_point = queued_data.size();
 227         }
 228
 229         if (encoding == Stream::STREAM_ENCODING_METACUBE) {
 230                 // Add a Metacube block header before the data.
 231                 metacube2_block_header hdr;
 232                 memcpy(hdr.sync, METACUBE2_SYNC, sizeof(hdr.sync));
 233                 hdr.size = htonl(bytes);
 234                 hdr.flags = htons(0);
 235                 if (suitable_for_stream_start == NOT_SUITABLE_FOR_STREAM_START) {
 236                         hdr.flags |= htons(METACUBE_FLAGS_NOT_SUITABLE_FOR_STREAM_START);
 237                 }
 238                 hdr.csum = htons(metacube2_compute_crc(&hdr));
 239
 240                 iovec iov;
 241                 iov.iov_base = new char[bytes + sizeof(hdr)];
 242                 iov.iov_len = bytes + sizeof(hdr);
 243
 244                 memcpy(iov.iov_base, &hdr, sizeof(hdr));
 245                 memcpy(reinterpret_cast<char *>(iov.iov_base) + sizeof(hdr), data, bytes);
 246
 247                 queued_data.push_back(iov);
 248         } else if (encoding == Stream::STREAM_ENCODING_RAW) {
 249                 // Just add the data itself.
 250                 iovec iov;
 251                 iov.iov_base = new char[bytes];
 252                 memcpy(iov.iov_base, data, bytes);
 253                 iov.iov_len = bytes;
 254
 255                 queued_data.push_back(iov);
 256         } else {
 257                 assert(false);
 258         }
 259 }
 260
 261 void Stream::process_queued_data()
 262 {
 263         std::vector<iovec> queued_data_copy;
 264         int queued_data_last_starting_point_copy = -1;
 265
 266         // Hold the lock for as short as possible, since add_data_raw() can possibly
 267         // write to disk, which might disturb the input thread.
 268         {
 269                 MutexLock lock(&queued_data_mutex);
 270                 if (queued_data.empty()) {
 271                         return;
 272                 }
 273
 274                 swap(queued_data, queued_data_copy);
 275                 swap(queued_data_last_starting_point, queued_data_last_starting_point_copy);
 276         }
 277
 278         // Update the last suitable starting point for the stream,
 279         // if the queued data contains such a starting point.
 280         assert(queued_data_last_starting_point_copy < ssize_t(queued_data_copy.size()));
 281         if (queued_data_last_starting_point_copy >= 0) {
 282                 last_suitable_starting_point = bytes_received;
 283                 for (int i = 0; i < queued_data_last_starting_point_copy; ++i) {
 284                         last_suitable_starting_point += queued_data_copy[i].iov_len;
 285                 }
 286         }
 287
 288         add_data_raw(queued_data_copy);
 289         for (size_t i = 0; i < queued_data_copy.size(); ++i) {
 290                 char *data = reinterpret_cast<char *>(queued_data_copy[i].iov_base);
 291                 delete[] data;
 292         }
 293
 294         // We have more data, so wake up all clients.
 295         if (to_process.empty()) {
 296                 swap(sleeping_clients, to_process);
 297         } else {
 298                 to_process.insert(to_process.end(), sleeping_clients.begin(), sleeping_clients.end());
 299                 sleeping_clients.clear();
 300         }
 301 }