Initial QSfera import

Server/vendor/github.com/r3labs/sse/v2/event.go

@@ -0,0 +1,114 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package sse
+
+import (
+	"bufio"
+	"bytes"
+	"context"
+	"io"
+	"time"
+)
+
+// Event holds all of the event source fields
+type Event struct {
+	timestamp time.Time
+	ID        []byte
+	Data      []byte
+	Event     []byte
+	Retry     []byte
+	Comment   []byte
+}
+
+func (e *Event) hasContent() bool {
+	return len(e.ID) > 0 || len(e.Data) > 0 || len(e.Event) > 0 || len(e.Retry) > 0
+}
+
+// EventStreamReader scans an io.Reader looking for EventStream messages.
+type EventStreamReader struct {
+	scanner *bufio.Scanner
+}
+
+// NewEventStreamReader creates an instance of EventStreamReader.
+func NewEventStreamReader(eventStream io.Reader, maxBufferSize int) *EventStreamReader {
+	scanner := bufio.NewScanner(eventStream)
+	initBufferSize := minPosInt(4096, maxBufferSize)
+	scanner.Buffer(make([]byte, initBufferSize), maxBufferSize)
+
+	split := func(data []byte, atEOF bool) (int, []byte, error) {
+		if atEOF && len(data) == 0 {
+			return 0, nil, nil
+		}
+
+		// We have a full event payload to parse.
+		if i, nlen := containsDoubleNewline(data); i >= 0 {
+			return i + nlen, data[0:i], nil
+		}
+		// If we're at EOF, we have all of the data.
+		if atEOF {
+			return len(data), data, nil
+		}
+		// Request more data.
+		return 0, nil, nil
+	}
+	// Set the split function for the scanning operation.
+	scanner.Split(split)
+
+	return &EventStreamReader{
+		scanner: scanner,
+	}
+}
+
+// Returns a tuple containing the index of a double newline, and the number of bytes
+// represented by that sequence. If no double newline is present, the first value
+// will be negative.
+func containsDoubleNewline(data []byte) (int, int) {
+	// Search for each potentially valid sequence of newline characters
+	crcr := bytes.Index(data, []byte("\r\r"))
+	lflf := bytes.Index(data, []byte("\n\n"))
+	crlflf := bytes.Index(data, []byte("\r\n\n"))
+	lfcrlf := bytes.Index(data, []byte("\n\r\n"))
+	crlfcrlf := bytes.Index(data, []byte("\r\n\r\n"))
+	// Find the earliest position of a double newline combination
+	minPos := minPosInt(crcr, minPosInt(lflf, minPosInt(crlflf, minPosInt(lfcrlf, crlfcrlf))))
+	// Detemine the length of the sequence
+	nlen := 2
+	if minPos == crlfcrlf {
+		nlen = 4
+	} else if minPos == crlflf || minPos == lfcrlf {
+		nlen = 3
+	}
+	return minPos, nlen
+}
+
+// Returns the minimum non-negative value out of the two values. If both
+// are negative, a negative value is returned.
+func minPosInt(a, b int) int {
+	if a < 0 {
+		return b
+	}
+	if b < 0 {
+		return a
+	}
+	if a > b {
+		return b
+	}
+	return a
+}
+
+// ReadEvent scans the EventStream for events.
+func (e *EventStreamReader) ReadEvent() ([]byte, error) {
+	if e.scanner.Scan() {
+		event := e.scanner.Bytes()
+		return event, nil
+	}
+	if err := e.scanner.Err(); err != nil {
+		if err == context.Canceled {
+			return nil, io.EOF
+		}
+		return nil, err
+	}
+	return nil, io.EOF
+}