Moved the polling of data from the webgui to its own dedicated poller.

This should simplify testing of webgui.

datasource/datapoller.go

@@ -0,0 +1,99 @@
+/*
+Copyright (c) 2015, Hendrik van Wyk
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice, this
+list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright notice,
+this list of conditions and the following disclaimer in the documentation
+and/or other materials provided with the distribution.
+
+* Neither the name of invertergui nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+package datasource
+
+import (
+	"sync"
+	"time"
+)
+
+type DataPoller interface {
+	C() chan *Status
+	Stop()
+}
+
+type Status struct {
+	MpStatus MultiplusStatus
+	Time     time.Time
+	Err      error
+}
+
+type poller struct {
+	source     DataSource
+	rate       time.Duration
+	statusChan chan *Status
+	stop       chan struct{}
+	wg         sync.WaitGroup
+}
+
+func NewDataPoller(source DataSource, pollRate time.Duration) DataPoller {
+	this := &poller{
+		source:     source,
+		rate:       pollRate,
+		statusChan: make(chan *Status),
+		stop:       make(chan struct{}),
+	}
+	this.wg.Add(1)
+	go this.poll()
+	return this
+}
+
+func (this *poller) C() chan *Status {
+	return this.statusChan
+}
+
+func (this *poller) Stop() {
+	close(this.stop)
+	this.wg.Wait()
+}
+
+func (this *poller) poll() {
+	ticker := time.NewTicker(this.rate)
+	this.doPoll()
+	for {
+		select {
+		case <-ticker.C:
+			this.doPoll()
+		case <-this.stop:
+			ticker.Stop()
+			close(this.statusChan)
+			this.wg.Done()
+			return
+		}
+	}
+}
+
+func (this *poller) doPoll() {
+	tmp := new(Status)
+	tmp.Err = this.source.GetData(&tmp.MpStatus)
+	tmp.Time = time.Now()
+	this.statusChan <- tmp
+}