X-Git-Url: https://git.sesse.net/?p=cubemap;a=blobdiff_plain;f=stream.cpp;h=557502bee006783f7b386540dd299586fc8ec67b;hp=7f4bce8c5825380f0be1b7e2ddfec9fcc328b903;hb=00cf4a1ffcb987ef6d27fcf49811fd5ef572a985;hpb=b2d3112addcc8da422f08708db29435b45d85afa

diff --git a/stream.cpp b/stream.cpp
index 7f4bce8..557502b 100644
--- a/stream.cpp
+++ b/stream.cpp
@@ -27,8 +27,7 @@ Stream::Stream(const string &url, size_t backlog_size, size_t prebuffering_bytes
 	  prebuffering_bytes(prebuffering_bytes),
 	  bytes_received(0),
 	  last_suitable_starting_point(-1),
-	  pacing_rate(~0U),
-	  queued_data_last_starting_point_index(-1)
+	  pacing_rate(~0U)
 {
 	if (data_fd == -1) {
 		exit(1);
@@ -53,8 +52,7 @@ Stream::Stream(const StreamProto &serialized, int data_fd)
 	  backlog_size(serialized.backlog_size()),
 	  prebuffering_bytes(serialized.prebuffering_bytes()),
 	  bytes_received(serialized.bytes_received()),
-	  pacing_rate(~0U),
-	  queued_data_last_starting_point_index(-1)
+	  pacing_rate(~0U)
 {
 	if (data_fd == -1) {
 		exit(1);
@@ -116,13 +114,36 @@ void Stream::set_backlog_size(size_t new_size)
 
 	// Now cheat a bit by rewinding, and adding all the old data back.
 	bytes_received -= existing_data.size();
-	iovec iov;
-	iov.iov_base = const_cast<char *>(existing_data.data());
-	iov.iov_len = existing_data.size();
 
-	vector<iovec> iovs;
-	iovs.push_back(iov);
-	add_data_raw(iovs);
+	size_t bytes_before_suitable_starting_point;
+	if (last_suitable_starting_point == -1) {
+		bytes_before_suitable_starting_point = existing_data.size();
+	} else if (size_t(last_suitable_starting_point) < backlog_size) {
+		bytes_before_suitable_starting_point = 0;
+	} else {
+		bytes_before_suitable_starting_point = last_suitable_starting_point - backlog_size;
+	}
+
+	vector<DataElement> data_elements;
+	if (bytes_before_suitable_starting_point > 0) {
+		// There's really no usable data here (except for ?backlog=1 users),
+		// but we need to get the accounting right anyway.
+		DataElement data_element;
+		data_element.data.iov_base = const_cast<char *>(existing_data.data());
+		data_element.data.iov_len = bytes_before_suitable_starting_point;
+		data_element.suitable_for_stream_start = NOT_SUITABLE_FOR_STREAM_START;
+		data_elements.push_back(data_element);
+	}
+	if (bytes_before_suitable_starting_point < existing_data.size()) {
+		DataElement data_element;
+		data_element.data.iov_base = const_cast<char *>(existing_data.data() + bytes_before_suitable_starting_point);
+		data_element.data.iov_len = existing_data.size() - bytes_before_suitable_starting_point;
+		data_element.suitable_for_stream_start = SUITABLE_FOR_STREAM_START;
+		data_elements.push_back(data_element);
+	}
+
+	last_suitable_starting_point = -1;
+	add_data_raw(data_elements);
 }
 
 void Stream::put_client_to_sleep(Client *client)
@@ -131,20 +152,20 @@ void Stream::put_client_to_sleep(Client *client)
 }
 
 // Return a new set of iovecs that contains only the first <bytes_wanted> bytes of <data>.
-vector<iovec> collect_iovecs(const vector<iovec> &data, size_t bytes_wanted)
+vector<iovec> collect_iovecs(const vector<Stream::DataElement> &data, size_t bytes_wanted)
 {
 	vector<iovec> ret;
 	size_t max_iovecs = std::min<size_t>(data.size(), IOV_MAX);
 	for (size_t i = 0; i < max_iovecs && bytes_wanted > 0; ++i) {
-		if (data[i].iov_len <= bytes_wanted) {
+		if (data[i].data.iov_len <= bytes_wanted) {
 			// Consume the entire iovec.
-			ret.push_back(data[i]);
-			bytes_wanted -= data[i].iov_len;
+			ret.push_back(data[i].data);
+			bytes_wanted -= data[i].data.iov_len;
 		} else {
 			// Take only parts of this iovec.
 			iovec iov;
-			iov.iov_base = data[i].iov_base;
-			iov.iov_len = bytes_wanted;	
+			iov.iov_base = data[i].data.iov_base;
+			iov.iov_len = bytes_wanted;
 			ret.push_back(iov);
 			bytes_wanted = 0;
 		}
@@ -153,20 +174,21 @@ vector<iovec> collect_iovecs(const vector<iovec> &data, size_t bytes_wanted)
 }
 
 // Return a new set of iovecs that contains all of <data> except the first <bytes_wanted> bytes.
-vector<iovec> remove_iovecs(const vector<iovec> &data, size_t bytes_wanted)
+vector<Stream::DataElement> remove_iovecs(const vector<Stream::DataElement> &data, size_t bytes_wanted)
 {
-	vector<iovec> ret;
+	vector<Stream::DataElement> ret;
 	size_t i;
 	for (i = 0; i < data.size() && bytes_wanted > 0; ++i) {
-		if (data[i].iov_len <= bytes_wanted) {
+		if (data[i].data.iov_len <= bytes_wanted) {
 			// Consume the entire iovec.
-			bytes_wanted -= data[i].iov_len;
+			bytes_wanted -= data[i].data.iov_len;
 		} else {
 			// Take only parts of this iovec.
-			iovec iov;
-			iov.iov_base = reinterpret_cast<char *>(data[i].iov_base) + bytes_wanted;
-			iov.iov_len = data[i].iov_len - bytes_wanted;
-			ret.push_back(iov);
+			Stream::DataElement data_element;
+			data_element.data.iov_base = reinterpret_cast<char *>(data[i].data.iov_base) + bytes_wanted;
+			data_element.data.iov_len = data[i].data.iov_len - bytes_wanted;
+			data_element.suitable_for_stream_start = NOT_SUITABLE_FOR_STREAM_START;
+			ret.push_back(data_element);
 			bytes_wanted = 0;
 		}
 	}
@@ -176,9 +198,9 @@ vector<iovec> remove_iovecs(const vector<iovec> &data, size_t bytes_wanted)
 	return ret;
 }
 
-void Stream::add_data_raw(const vector<iovec> &orig_data)
+void Stream::add_data_raw(const vector<DataElement> &orig_data)
 {
-	vector<iovec> data = orig_data;
+	vector<DataElement> data = orig_data;
 	while (!data.empty()) {
 		size_t pos = bytes_received % backlog_size;
 
@@ -207,9 +229,9 @@ void Stream::add_data_deferred(const char *data, size_t bytes, StreamStartSuitab
 	MutexLock lock(&queued_data_mutex);
 	assert(suitable_for_stream_start == SUITABLE_FOR_STREAM_START ||
 	       suitable_for_stream_start == NOT_SUITABLE_FOR_STREAM_START);
-	if (suitable_for_stream_start == SUITABLE_FOR_STREAM_START) {
-		queued_data_last_starting_point_index = queued_data.size();
-	}
+
+	DataElement data_element;
+	data_element.suitable_for_stream_start = suitable_for_stream_start;
 
 	if (encoding == Stream::STREAM_ENCODING_METACUBE) {
 		// Add a Metacube block header before the data.
@@ -222,22 +244,20 @@ void Stream::add_data_deferred(const char *data, size_t bytes, StreamStartSuitab
 		}
 		hdr.csum = htons(metacube2_compute_crc(&hdr));
 
-		iovec iov;
-		iov.iov_base = new char[bytes + sizeof(hdr)];
-		iov.iov_len = bytes + sizeof(hdr);
+		data_element.data.iov_base = new char[bytes + sizeof(hdr)];
+		data_element.data.iov_len = bytes + sizeof(hdr);
 
-		memcpy(iov.iov_base, &hdr, sizeof(hdr));
-		memcpy(reinterpret_cast<char *>(iov.iov_base) + sizeof(hdr), data, bytes);
+		memcpy(data_element.data.iov_base, &hdr, sizeof(hdr));
+		memcpy(reinterpret_cast<char *>(data_element.data.iov_base) + sizeof(hdr), data, bytes);
 
-		queued_data.push_back(iov);
+		queued_data.push_back(data_element);
 	} else if (encoding == Stream::STREAM_ENCODING_RAW) {
 		// Just add the data itself.
-		iovec iov;
-		iov.iov_base = new char[bytes];
-		memcpy(iov.iov_base, data, bytes);
-		iov.iov_len = bytes;
+		data_element.data.iov_base = new char[bytes];
+		memcpy(data_element.data.iov_base, data, bytes);
+		data_element.data.iov_len = bytes;
 
-		queued_data.push_back(iov);
+		queued_data.push_back(data_element);
 	} else {
 		assert(false);
 	}
@@ -245,8 +265,7 @@ void Stream::add_data_deferred(const char *data, size_t bytes, StreamStartSuitab
 
 void Stream::process_queued_data()
 {
-	std::vector<iovec> queued_data_copy;
-	int queued_data_last_starting_point_index_copy = -1;
+	std::vector<DataElement> queued_data_copy;
 
 	// Hold the lock for as short as possible, since add_data_raw() can possibly
 	// write to disk, which might disturb the input thread.
@@ -257,22 +276,21 @@ void Stream::process_queued_data()
 		}
 
 		swap(queued_data, queued_data_copy);
-		swap(queued_data_last_starting_point_index, queued_data_last_starting_point_index_copy);
 	}
 
 	// Update the last suitable starting point for the stream,
 	// if the queued data contains such a starting point.
-	assert(queued_data_last_starting_point_index_copy < ssize_t(queued_data_copy.size()));
-	if (queued_data_last_starting_point_index_copy >= 0) {
-		last_suitable_starting_point = bytes_received;
-		for (int i = 0; i < queued_data_last_starting_point_index_copy; ++i) {
-			last_suitable_starting_point += queued_data_copy[i].iov_len;
+	size_t byte_position = bytes_received;
+	for (size_t i = 0; i < queued_data_copy.size(); ++i) {
+		if (queued_data_copy[i].suitable_for_stream_start == SUITABLE_FOR_STREAM_START) {
+			last_suitable_starting_point = byte_position;
 		}
+		byte_position += queued_data_copy[i].data.iov_len;
 	}
 
 	add_data_raw(queued_data_copy);
 	for (size_t i = 0; i < queued_data_copy.size(); ++i) {
-		char *data = reinterpret_cast<char *>(queued_data_copy[i].iov_base);
+		char *data = reinterpret_cast<char *>(queued_data_copy[i].data.iov_base);
 		delete[] data;
 	}