Rework to add and use a binding for radio controldab_3.99.1dab/3.99.13.99.1

A radio binding has been added in the new binding directory, and the
application has been reworked to use it.  The binding uses a modified
version of the rtl_fm code used in the qtmultimedia radio plugin that
was previously used, and some new code has been added to output to
PulseAudio using the asynchronous API to ensure compatibility with
stream corking.  The rtl_fm code has been enhanced to add seeking
support, and the application has been tweaked to use it.

Bug-AGL: SPEC-581

Change-Id: I011e98374accc2cad2b36c93ac800948ee51f2aa
Signed-off-by: Scott Murray <scott.murray@konsulko.com>

1 files changed, 196 insertions, 0 deletions

diff --git a/app/api/Binding.qml b/app/api/Binding.qml
new file mode 100644
index 0000000..3b43510
--- /dev/null
+++ b/app/api/Binding.qml
@@ -0,0 +1,196 @@
+/*
+ * Copyright (C) 2016 The Qt Company Ltd.
+ * Copyright (C) 2017 Konsulko Group
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import QtQuick 2.6
+import QtWebSockets 1.0
+
+WebSocket {
+    id: root
+    active: true
+    url: bindingAddress
+
+    property string apiString: "radio"
+    property var verbs: []
+    property string payloadLength: "9999"
+
+    readonly property var msgid: {
+         "call": 2,
+         "retok": 3,
+         "reterr": 4,
+         "event": 5
+    }
+
+    readonly property int amBand: 0
+    readonly property int fmBand: 1
+
+    readonly property int stoppedState: 0
+    readonly property int activeState: 1
+
+    property int band: fmBand
+    property int frequency
+    property int frequencyStep
+    property int minimumFrequency
+    property int maximumFrequency
+    property int state: stoppedState
+    property int scanningState: stoppedState
+    property bool scanningFreqUpdate: false
+    property string stationId: ""
+
+    signal stationFound
+
+    property Connections c : Connections {
+        target: root
+
+        onFrequencyChanged: {
+            if(scanningState != activeState) {
+                // Not scanning, push update
+                sendSocketMessage("frequency", { value: frequency })
+            } else if(!scanningFreqUpdate) {
+                // External change, stop scanning
+                sendSocketMessage("scan_stop", 'None')
+                scanningState = stoppedState
+                sendSocketMessage("frequency", { value: frequency })
+            } else {
+                // This update was from scanning, clear state
+                scanningFreqUpdate = false
+            }
+        }
+
+        onBandChanged: {
+            sendSocketMessage("band", { value: band })
+            updateFrequencyRange(band)
+            updateFrequencyStep(band)
+            frequency = minimumFrequency
+        }
+    }
+
+    onTextMessageReceived: {
+        var json = JSON.parse(message)
+        //console.debug("Raw response: " + message)
+        var request = json[2].request
+        var response = json[2].response
+
+        switch (json[0]) {
+        case msgid.call:
+            break
+        case msgid.retok:
+            var verb = verbs.shift()
+            if (verb == "frequency_range") {
+                minimumFrequency = response.min
+                maximumFrequency = response.max
+            } else if (verb == "frequency_step") {
+                frequencyStep = response.step
+            }
+            break
+        case msgid.event:
+            var event = JSON.parse(JSON.stringify(json[2]))
+            if (event.event === "radio/frequency") {
+                if(scanningState == activeState) {
+                    scanningFreqUpdate = true
+                    frequency = event.data.value
+                }
+            } else if (event.event === "radio/station_found") {
+                if(scanningState == activeState) {
+                    scanningState = stoppedState
+                    stationId = freq2str(event.data.value)
+                    root.stationFound()
+                }
+            }
+            break
+        case msg.reterr:
+            console.debug("Bad return value, binding probably not installed")
+            break
+        case MessageId.event:
+            break
+        }
+    }
+
+    onStatusChanged: {
+        switch (status) {
+        case WebSocket.Open:
+            // Initialize band values now that we're connected to the
+            // binding
+            updateFrequencyRange(band)
+            updateFrequencyStep(band)
+            frequency = minimumFrequency
+            sendSocketMessage("subscribe", { value: "frequency" })
+            sendSocketMessage("subscribe", { value: "station_found" })
+            break
+        case WebSocket.Error:
+            console.debug("WebSocket error: " + root.errorString)
+            break
+        }
+    }
+
+    function freq2str(freq) {
+        if (freq > 5000000) {
+            return '%1 MHz'.arg((freq / 1000000).toFixed(1))
+        } else {
+            return '%1 kHz'.arg((freq / 1000).toFixed(0))
+        }
+    }
+
+    function sendSocketMessage(verb, parameter) {
+        var requestJson = [ msgid.call, payloadLength, apiString + '/'
+                           + verb, parameter ]
+        //console.debug("sendSocketMessage: " + JSON.stringify(requestJson))
+        verbs.push(verb)
+        sendTextMessage(JSON.stringify(requestJson))
+    }
+
+    function start() {
+        sendSocketMessage("start", 'None')
+        state = activeState
+    }
+
+    function stop() {
+        sendSocketMessage("stop", 'None')
+        state = stoppedState
+    }
+
+    function tuneUp() {
+        frequency += frequencyStep
+	if(frequency > maximumFrequency) {
+            frequency = minimumFrequency
+        }
+    }
+
+    function tuneDown() {
+        frequency -= frequencyStep
+	if(frequency < minimumFrequency) {
+            frequency = maximumFrequency
+        }
+    }
+
+    function scanUp() {
+        scanningState = activeState
+        sendSocketMessage("scan_start", { direction: "forward" })
+    }
+
+    function scanDown() {
+        scanningState = activeState
+        sendSocketMessage("scan_start", { direction: "backward" })
+    }
+
+    function updateFrequencyRange(band) {
+        sendSocketMessage("frequency_range", { band: band })
+    }
+
+    function updateFrequencyStep(band) {
+        sendSocketMessage("frequency_step", { band: band })
+    }
+}