Ability for controller to share data at runtime

CMakeLists.txt

@@ -739,6 +739,7 @@ add_library(mixxx-lib STATIC EXCLUDE_FROM_ALL
   src/controllers/controlpickermenu.cpp
   src/controllers/legacycontrollermappingfilehandler.cpp
   src/controllers/legacycontrollermapping.cpp
+  src/controllers/controllershareddata.cpp
   src/controllers/delegates/controldelegate.cpp
   src/controllers/delegates/midibytedelegate.cpp
   src/controllers/delegates/midichanneldelegate.cpp
@@ -2099,6 +2100,7 @@ add_executable(mixxx-test
   src/test/controller_mapping_settings_test.cpp
   src/test/controllers/controller_columnid_regression_test.cpp
   src/test/controllerscriptenginelegacy_test.cpp
+  src/test/controllershareddata_test.cpp
   src/test/controlobjecttest.cpp
   src/test/controlobjectaliastest.cpp
   src/test/controlobjectscripttest.cpp

res/controllers/engine-api.d.ts

@@ -25,6 +25,7 @@ declare interface ScriptConnection {
 
 declare namespace engine {
     type SettingValue = string | number | boolean;
+    type SharedDataValue = string | number | boolean | object | array | undefined;
     /**
      * Gets the value of a controller setting
      * The value is either set in the preferences dialog,
@@ -72,6 +73,28 @@ declare namespace engine {
      */
     function setParameter(group: string, name: string, newValue: number): void;
 
+    /**
+     * Gets the shared runtime data.
+     * @returns Runtime shared data value
+     */
+    function getSharedData(): SharedDataValue;
+
+    /**
+     * Override the the shared runtime data with a new value.
+     *
+     * It is suggested to make additive changes (e.g add new attribute to existing object) in order to ease integration with other controller mapping
+     * @param newValue Runtime shared data value to be set
+     */
+   function setSharedData(newValue: SharedDataValue): void;
+
+    /**
+     * Sets the control value specified with normalized range of 0..1
+     * @param group Group of the control e.g. "[Channel1]"
+     * @param name Name of the control e.g. "play_indicator"
+     * @param newValue Value to be set, normalized to a range of 0..1
+     */
+    function setParameter(group: string, name: string, newValue: number): void;
+
     /**
      * Normalizes a specified value using the range of the given control,
      * to the range of 0..1
@@ -112,6 +135,7 @@ declare namespace engine {
     function getDefaultParameter(group: string, name: string): number;
 
     type CoCallback = (value: number, group: string, name: string) => void
+    type RuntimeSharedDataCallback = (value: SharedDataValue) => void
 
     /**
      * Connects a specified Mixxx Control with a callback function, which is executed if the value of the control changes
@@ -121,9 +145,18 @@ declare namespace engine {
      * @param group Group of the control e.g. "[Channel1]"
      * @param name Name of the control e.g. "play_indicator"
      * @param callback JS function, which will be called every time, the value of the connected control changes.
-     * @returns Returns script connection object on success, otherwise 'undefined''
+     * @returns Returns script connection object on success, otherwise 'undefined'
+     */
+    function makeConnection(group: string, name: string, callback: CoCallback): ScriptConnection | undefined;
+
+    /**
+     * Register callback function to be triggered when the shared data is updated
+     *
+     * Note that local update will also trigger the callback. Make sure to make your callback safe against recursion.
+     * @param callback JS function, which will be called every time, the shared controller value changes.
+     * @returns Returns script connection object on success, otherwise 'undefined'
      */
-    function makeConnection(group: string, name: string, callback: CoCallback): ScriptConnection |undefined;
+    function makeSharedDataConnection(callback: RuntimeSharedDataCallback): ScriptConnection | undefined;
 
     /**
      * Connects a specified Mixxx Control with a callback function, which is executed if the value of the control changes

src/controllers/controller.cpp

@@ -3,6 +3,7 @@
 #include <QJSEngine>
 #include <algorithm>
 
+#include "controllers/controllershareddata.h"
 #include "controllers/scripting/legacy/controllerscriptenginelegacy.h"
 #include "moc_controller.cpp"
 #include "util/cmdlineargs.h"
@@ -62,7 +63,7 @@ void Controller::stopEngine() {
     m_pScriptEngineLegacy = nullptr;
 }
 
-bool Controller::applyMapping() {
+bool Controller::applyMapping(std::shared_ptr<ControllerSharedData> runtimeData) {
     qCInfo(m_logBase) << "Applying controller mapping...";
 
     const std::shared_ptr<LegacyControllerMapping> pMapping = cloneMapping();
@@ -84,6 +85,11 @@ bool Controller::applyMapping() {
     m_pScriptEngineLegacy->setScriptFiles(scriptFiles);
 
     m_pScriptEngineLegacy->setSettings(pMapping->getSettings());
+
+    const auto& ns = pMapping->sharedDataNamespace();
+    if (!ns.isEmpty() && runtimeData != nullptr) {
+        m_pScriptEngineLegacy->setSharedData(runtimeData->namespaced(ns));
+    }
     return m_pScriptEngineLegacy->initialize();
 }
 

src/controllers/controller.h

@@ -8,6 +8,7 @@
 
 class ControllerJSProxy;
 class ControllerScriptEngineLegacy;
+class ControllerSharedData;
 
 /// This is a base class representing a physical (or software) controller.  It
 /// must be inherited by a class that implements it on some API. Note that the
@@ -70,7 +71,7 @@ class Controller : public QObject {
     // this if they have an alternate way of handling such data.)
     virtual void receive(const QByteArray& data, mixxx::Duration timestamp);
 
-    virtual bool applyMapping();
+    virtual bool applyMapping(std::shared_ptr<ControllerSharedData> runtimeData);
     virtual void slotBeforeEngineShutdown();
 
     // Puts the controller in and out of learning mode.
@@ -137,7 +138,6 @@ class Controller : public QObject {
     const RuntimeLoggingCategory m_logOutput;
 
   private: // but used by ControllerManager
-
     virtual int open() = 0;
     virtual int close() = 0;
     // Requests that the device poll if it is a polling device. Returns true

src/controllers/controllermanager.cpp

@@ -6,7 +6,9 @@
 #include "controllers/controller.h"
 #include "controllers/controllerlearningeventfilter.h"
 #include "controllers/controllermappinginfoenumerator.h"
+#include "controllers/controllershareddata.h"
 #include "controllers/defs_controllers.h"
+#include "controllers/scripting/legacy/controllerscriptenginelegacy.h"
 #include "moc_controllermanager.cpp"
 #include "util/cmdlineargs.h"
 #include "util/compatibility/qmutex.h"
@@ -93,7 +95,8 @@ ControllerManager::ControllerManager(UserSettingsPointer pConfig)
           // its own event loop.
           m_pControllerLearningEventFilter(new ControllerLearningEventFilter()),
           m_pollTimer(this),
-          m_skipPoll(false) {
+          m_skipPoll(false),
+          m_pRuntimeData(std::make_shared<ControllerSharedData>(this)) {
     qRegisterMetaType<std::shared_ptr<LegacyControllerMapping>>(
             "std::shared_ptr<LegacyControllerMapping>");
 
@@ -300,7 +303,12 @@ void ControllerManager::slotSetUpDevices() {
             qWarning() << "There was a problem opening" << name;
             continue;
         }
-        pController->applyMapping();
+        VERIFY_OR_DEBUG_ASSERT(pController->getScriptEngine()) {
+            qWarning() << "Unable to acquire the controller engine. Has the "
+                          "controller open successfully?";
+            continue;
+        }
+        pController->applyMapping(m_pRuntimeData);
     }
 
     pollIfAnyControllersOpen();
@@ -392,7 +400,13 @@ void ControllerManager::openController(Controller* pController) {
     // If successfully opened the device, apply the mapping and save the
     // preference setting.
     if (result == 0) {
-        pController->applyMapping();
+        VERIFY_OR_DEBUG_ASSERT(pController->getScriptEngine()) {
+            qWarning() << "Unable to acquire the controller engine. Has the "
+                          "controller open successfully?";
+            return;
+        }
+
+        pController->applyMapping(m_pRuntimeData);
 
         // Update configuration to reflect controller is enabled.
         m_pConfig->setValue(

src/controllers/controllermanager.h

@@ -14,6 +14,7 @@ class Controller;
 class ControllerLearningEventFilter;
 class MappingInfoEnumerator;
 class LegacyControllerMapping;
+class ControllerSharedData;
 class ControllerEnumerator;
 
 /// Function to sort controllers by name
@@ -86,4 +87,5 @@ class ControllerManager : public QObject {
     QSharedPointer<MappingInfoEnumerator> m_pMainThreadUserMappingEnumerator;
     QSharedPointer<MappingInfoEnumerator> m_pMainThreadSystemMappingEnumerator;
     bool m_skipPoll;
+    std::shared_ptr<ControllerSharedData> m_pRuntimeData;
 };

src/controllers/controllershareddata.cpp

@@ -0,0 +1,21 @@
+#include <controllers/controllershareddata.h>
+
+#include "moc_controllershareddata.cpp"
+
+ControllerNamespacedSharedData* ControllerSharedData::namespaced(const QString& ns) {
+    return new ControllerNamespacedSharedData(this, ns);
+}
+
+ControllerNamespacedSharedData::ControllerNamespacedSharedData(
+        ControllerSharedData* parent, const QString& ns)
+        : QObject(parent), m_namespace(ns) {
+    connect(parent,
+            &ControllerSharedData::updated,
+            this,
+            [this](const QString& ns, const QVariant& value) {
+                if (ns != m_namespace) {
+                    return;
+                }
+                emit updated(value);
+            });
+}

src/controllers/controllershareddata.h

@@ -0,0 +1,67 @@
+#pragma once
+
+#include <QVariant>
+
+#include "util/assert.h"
+
+class ControllerNamespacedSharedData;
+
+/// ControllerSharedData is a wrapper that allows controllers script runtimes
+/// to share arbitrary data via a the JavaScript interface. Controllers don't
+/// access this object directly, and instead uses the
+/// ControllerNamespacedSharedData wrapper to isolate a specific namespace and
+/// prevent potential clash
+class ControllerSharedData : public QObject {
+    Q_OBJECT
+  public:
+    ControllerSharedData(QObject* parent)
+            : QObject(parent), m_value() {
+    }
+
+    QVariant get(const QString& ns) const {
+        return m_value.value(ns);
+    }
+
+    /// @brief Create a a namespace wrapper that can be used by a controller.
+    /// The caller is owning the wrapper
+    /// @param ns The namespace to restrict access to
+    /// @return The pointer to the newly allocated wrapper
+    ControllerNamespacedSharedData* namespaced(const QString& ns);
+
+  public slots:
+    void set(const QString& ns, const QVariant& value) {
+        m_value[ns] = value;
+        emit updated(ns, m_value[ns]);
+    }
+
+  signals:
+    void updated(const QString& ns, const QVariant& value);
+
+  private:
+    QHash<QString, QVariant> m_value;
+};
+
+/// ControllerNamespacedSharedData is a wrapper that restrict access to a given
+/// namespace. It doesn't hold any data and can safely be deleted at all time,
+/// but only provide the namespace abstraction for controller to interact with
+/// via a the JavaScript interface
+class ControllerNamespacedSharedData : public QObject {
+    Q_OBJECT
+  public:
+    ControllerNamespacedSharedData(ControllerSharedData* parent, const QString& ns);
+
+    QVariant get() const {
+        return static_cast<ControllerSharedData*>(parent())->get(m_namespace);
+    }
+
+  public slots:
+    void set(const QVariant& value) {
+        static_cast<ControllerSharedData*>(parent())->set(m_namespace, value);
+    }
+
+  signals:
+    void updated(const QVariant& value);
+
+  private:
+    QString m_namespace;
+};

src/controllers/legacycontrollermapping.h

@@ -22,6 +22,7 @@ class LegacyControllerMapping {
             : m_productMatches(other.m_productMatches),
               m_bDirty(other.m_bDirty),
               m_deviceId(other.m_deviceId),
+              m_sharedDataNamespace(other.m_sharedDataNamespace),
               m_filePath(other.m_filePath),
               m_name(other.m_name),
               m_author(other.m_author),
@@ -161,6 +162,15 @@ class LegacyControllerMapping {
         return m_deviceId;
     }
 
+    void setSharedDataNamespace(QString sharedDataNamespace) {
+        m_sharedDataNamespace = std::move(sharedDataNamespace);
+        setDirty(true);
+    }
+
+    const QString& sharedDataNamespace() const {
+        return m_sharedDataNamespace;
+    }
+
     void setFilePath(const QString& filePath) {
         m_filePath = filePath;
         setDirty(true);
@@ -277,6 +287,7 @@ class LegacyControllerMapping {
     bool m_bDirty;
 
     QString m_deviceId;
+    QString m_sharedDataNamespace;
     QString m_filePath;
     QString m_name;
     QString m_author;

src/controllers/legacycontrollermappingfilehandler.cpp

@@ -210,6 +210,12 @@ void LegacyControllerMappingFileHandler::addScriptFilesToMapping(
 
     QString deviceId = controller.attribute("id", "");
     mapping->setDeviceId(deviceId);
+    // Empty namespace is forbidden. If a controller wants to use shared data,
+    // they must specify an non-empty string.
+    QString sharedDataNamespace = controller.attribute("namespace", "");
+    if (!sharedDataNamespace.isEmpty()) {
+        mapping->setSharedDataNamespace(deviceId);
+    }
 
     // See TODO in LegacyControllerMapping::DeviceDirection - `direction` should
     // only be used as a workaround till the bulk integration gets refactored

src/controllers/midi/midicontroller.cpp

@@ -76,9 +76,9 @@ bool MidiController::matchMapping(const MappingInfo& mapping) {
     return false;
 }
 
-bool MidiController::applyMapping() {
+bool MidiController::applyMapping(std::shared_ptr<ControllerSharedData> runtimeData) {
     // Handles the engine
-    bool result = Controller::applyMapping();
+    bool result = Controller::applyMapping(std::move(runtimeData));
 
     // Only execute this code if this is an output device
     if (isOutputDevice()) {

src/controllers/midi/midicontroller.h

@@ -9,6 +9,7 @@
 #include "controllers/softtakeover.h"
 
 class MidiOutputHandler;
+class ControllerSharedData;
 
 class MidiInputHandleJSProxy final : public QObject {
     Q_OBJECT
@@ -81,7 +82,7 @@ class MidiController : public Controller {
     void slotBeforeEngineShutdown() override;
 
   private slots:
-    bool applyMapping() override;
+    bool applyMapping(std::shared_ptr<ControllerSharedData>) override;
 
     void learnTemporaryInputMappings(const MidiInputMappings& mappings);
     void clearTemporaryInputMappings();

src/controllers/scripting/controllerscriptenginebase.cpp

@@ -218,3 +218,7 @@ void ControllerScriptEngineBase::errorDialogButton(
 void ControllerScriptEngineBase::throwJSError(const QString& message) {
     m_pJSEngine->throwError(message);
 }
+
+void ControllerScriptEngineBase::setSharedData(ControllerNamespacedSharedData* runtimeData) {
+    m_runtimeData = std::unique_ptr<ControllerNamespacedSharedData>(runtimeData);
+}