Add signal support to Godot Android plugin:

Supports registering and emitting signal from a Godot Android plugin

2 files changed, 182 insertions, 1 deletions

diff --git a/platform/android/java/lib/src/org/godotengine/godot/plugin/GodotPlugin.java b/platform/android/java/lib/src/org/godotengine/godot/plugin/GodotPlugin.java
index e3683704e1..a051164d15 100644
--- a/platform/android/java/lib/src/org/godotengine/godot/plugin/GodotPlugin.java
+++ b/platform/android/java/lib/src/org/godotengine/godot/plugin/GodotPlugin.java
@@ -34,6 +34,8 @@ import android.app.Activity;
 import android.content.Intent;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
+import android.text.TextUtils;
+import android.util.Log;
 import android.view.Surface;
 import android.view.View;
 import java.lang.reflect.Method;
@@ -41,8 +43,10 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
 import javax.microedition.khronos.egl.EGLConfig;
 import javax.microedition.khronos.opengles.GL10;
+import org.godotengine.godot.BuildConfig;
 import org.godotengine.godot.Godot;
 
 /**
@@ -70,7 +74,10 @@ import org.godotengine.godot.Godot;
  */
 public abstract class GodotPlugin {
 
+	private static final String TAG = GodotPlugin.class.getSimpleName();
+
 	private final Godot godot;
+	private final ConcurrentHashMap<String, SignalInfo> registeredSignals = new ConcurrentHashMap<>();
 
 	public GodotPlugin(Godot godot) {
 		this.godot = godot;
@@ -118,6 +125,13 @@ public abstract class GodotPlugin {
 			nativeRegisterMethod(getPluginName(), method.getName(), method.getReturnType().getName(), pt);
 		}
 
+		// Register the signals for this plugin.
+		for (SignalInfo signalInfo : getPluginSignals()) {
+			String signalName = signalInfo.getName();
+			nativeRegisterSignal(getPluginName(), signalName, signalInfo.getParamTypesNames());
+			registeredSignals.put(signalName, signalInfo);
+		}
+
 		// Get the list of gdnative libraries to register.
 		Set<String> gdnativeLibrariesPaths = getPluginGDNativeLibrariesPaths();
 		if (!gdnativeLibrariesPaths.isEmpty()) {
@@ -220,7 +234,17 @@ public abstract class GodotPlugin {
 	 * Returns the list of methods to be exposed to Godot.
 	 */
 	@NonNull
-	public abstract List<String> getPluginMethods();
+	public List<String> getPluginMethods() {
+		return Collections.emptyList();
+	}
+
+	/**
+	 * Returns the list of signals to be exposed to Godot.
+	 */
+	@NonNull
+	public Set<SignalInfo> getPluginSignals() {
+		return Collections.emptySet();
+	}
 
 	/**
 	 * Returns the paths for the plugin's gdnative libraries.
@@ -253,6 +277,49 @@ public abstract class GodotPlugin {
 	}
 
 	/**
+	 * Emit a registered Godot signal.
+	 * @param signalName
+	 * @param signalArgs
+	 */
+	protected void emitSignal(final String signalName, final Object... signalArgs) {
+		try {
+			// Check that the given signal is among the registered set.
+			SignalInfo signalInfo = registeredSignals.get(signalName);
+			if (signalInfo == null) {
+				throw new IllegalArgumentException(
+						"Signal " + signalName + " is not registered for this plugin.");
+			}
+
+			// Validate the arguments count.
+			Class<?>[] signalParamTypes = signalInfo.getParamTypes();
+			if (signalArgs.length != signalParamTypes.length) {
+				throw new IllegalArgumentException(
+						"Invalid arguments count. Should be " + signalParamTypes.length + "  but is " + signalArgs.length);
+			}
+
+			// Validate the argument's types.
+			for (int i = 0; i < signalParamTypes.length; i++) {
+				if (!signalParamTypes[i].isInstance(signalArgs[i])) {
+					throw new IllegalArgumentException(
+							"Invalid type for argument #" + i + ". Should be of type " + signalParamTypes[i].getName());
+				}
+			}
+
+			runOnRenderThread(new Runnable() {
+				@Override
+				public void run() {
+					nativeEmitSignal(getPluginName(), signalName, signalArgs);
+				}
+			});
+		} catch (IllegalArgumentException exception) {
+			Log.w(TAG, exception.getMessage());
+			if (BuildConfig.DEBUG) {
+				throw exception;
+			}
+		}
+	}
+
+	/**
 	 * Used to setup a {@link GodotPlugin} instance.
 	 * @param p_name Name of the instance.
 	 */
@@ -272,4 +339,20 @@ public abstract class GodotPlugin {
 	 * @param gdnlibPaths Paths to the libraries relative to the 'assets' directory.
 	 */
 	private native void nativeRegisterGDNativeLibraries(String[] gdnlibPaths);
+
+	/**
+	 * Used to complete registration of the {@link GodotPlugin} instance's methods.
+	 * @param pluginName Name of the plugin
+	 * @param signalName Name of the signal to register
+	 * @param signalParamTypes Signal parameters types
+	 */
+	private native void nativeRegisterSignal(String pluginName, String signalName, String[] signalParamTypes);
+
+	/**
+	 * Used to emit signal by {@link GodotPlugin} instance.
+	 * @param pluginName Name of the plugin
+	 * @param signalName Name of the signal to emit
+	 * @param signalParams Signal parameters
+	 */
+	private native void nativeEmitSignal(String pluginName, String signalName, Object[] signalParams);
 }
diff --git a/platform/android/java/lib/src/org/godotengine/godot/plugin/SignalInfo.java b/platform/android/java/lib/src/org/godotengine/godot/plugin/SignalInfo.java
new file mode 100644
index 0000000000..f907706889
--- /dev/null
+++ b/platform/android/java/lib/src/org/godotengine/godot/plugin/SignalInfo.java
@@ -0,0 +1,98 @@
+/*************************************************************************/
+/*  SignalInfo.java                                                      */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2019 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2019 Godot Engine contributors (cf. AUTHORS.md)    */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+package org.godotengine.godot.plugin;
+
+import android.support.annotation.NonNull;
+import android.text.TextUtils;
+import java.util.Arrays;
+
+/**
+ * Store information about a {@link GodotPlugin}'s signal.
+ */
+public final class SignalInfo {
+
+	private final String name;
+	private final Class<?>[] paramTypes;
+	private final String[] paramTypesNames;
+
+	public SignalInfo(@NonNull String signalName, Class<?>... paramTypes) {
+		if (TextUtils.isEmpty(signalName)) {
+			throw new IllegalArgumentException("Invalid signal name: " + signalName);
+		}
+
+		this.name = signalName;
+		this.paramTypes = paramTypes == null ? new Class<?>[ 0 ] : paramTypes;
+		this.paramTypesNames = new String[this.paramTypes.length];
+		for (int i = 0; i < this.paramTypes.length; i++) {
+			this.paramTypesNames[i] = this.paramTypes[i].getName();
+		}
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	Class<?>[] getParamTypes() {
+		return paramTypes;
+	}
+
+	String[] getParamTypesNames() {
+		return paramTypesNames;
+	}
+
+	@Override
+	public String toString() {
+		return "SignalInfo{"
+				+
+				"name='" + name + '\'' +
+				", paramsTypes=" + Arrays.toString(paramTypes) +
+				'}';
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		if (this == o) {
+			return true;
+		}
+		if (!(o instanceof SignalInfo)) {
+			return false;
+		}
+
+		SignalInfo that = (SignalInfo)o;
+
+		return name.equals(that.name);
+	}
+
+	@Override
+	public int hashCode() {
+		return name.hashCode();
+	}
+}