Add executeas() to change player/label context when running a closure

Author: PseudoKnight

src/main/java/com/laytonsmith/core/functions/DataHandling.java

@@ -1,6 +1,7 @@
 package com.laytonsmith.core.functions;
 
 import com.laytonsmith.PureUtilities.Version;
+import com.laytonsmith.abstraction.MCCommandSender;
 import com.laytonsmith.annotations.api;
 import com.laytonsmith.annotations.breakable;
 import com.laytonsmith.annotations.core;
@@ -3217,6 +3218,79 @@ public CHVersion since() {
 		}
 	}
 
+	@api
+	@seealso({com.laytonsmith.tools.docgen.templates.Closures.class})
+	public static class executeas extends AbstractFunction {
+
+		@Override
+		public String getName() {
+			return "executeas";
+		}
+
+		@Override
+		public Integer[] numArgs() {
+			return new Integer[]{Integer.MAX_VALUE};
+		}
+
+		@Override
+		public String docs() {
+			return "mixed {player, label, [values...,] closure} Executes the given closure in the context of a given"
+					+ " player. A closure that runs player(), for instance, would return the specified player's name."
+					+ " The label argument sets the permission label that this closure will use. If null is given,"
+					+ " the current label will be used, like with execute().";
+		}
+
+		@Override
+		public Class<? extends CREThrowable>[] thrown() {
+			return new Class[]{CRECastException.class};
+		}
+
+		@Override
+		public Boolean runAsync() {
+			return null;
+		}
+
+		@Override
+		public boolean isRestricted() {
+			return true;
+		}
+
+		@Override
+		public Construct exec(Target t, Environment environment, Construct... args) throws ConfigRuntimeException {
+			if(!(args[args.length - 1] instanceof CClosure)) {
+				throw new CRECastException("Only a closure (created from the closure function) can be sent to executeas()", t);
+			}
+			Construct[] vals = new Construct[args.length - 3];
+			System.arraycopy(args, 2, vals, 0, args.length - 3);
+			CClosure closure = (CClosure) args[args.length - 1];
+			CommandHelperEnvironment cEnv = closure.getEnv().getEnv(CommandHelperEnvironment.class);
+			GlobalEnv gEnv = closure.getEnv().getEnv(GlobalEnv.class);
+
+			MCCommandSender originalSender = cEnv.GetCommandSender();
+			cEnv.SetCommandSender(Static.GetCommandSender(args[0].val(), t));
+
+			String originalLabel = gEnv.GetLabel();
+			if(!(args[1] instanceof CNull)) {
+				gEnv.SetLabel(args[1].val());
+			}
+
+			try {
+				closure.execute(vals);
+			} catch (FunctionReturnException e) {
+				return e.getReturn();
+			} finally {
+				cEnv.SetCommandSender(originalSender);
+				gEnv.SetLabel(originalLabel);
+			}
+			return CVoid.VOID;
+		}
+
+		@Override
+		public CHVersion since() {
+			return CHVersion.V3_3_2;
+		}
+	}
+
 	@api
 	public static class _boolean extends AbstractFunction implements Optimizable {
 

src/test/java/com/laytonsmith/core/functions/DataHandlingTest.java

@@ -49,6 +49,7 @@ public static void tearDownClass() throws Exception {
 	public void setUp() {
 		fakePlayer = StaticTest.GetOnlinePlayer();
 		fakeServer = StaticTest.GetFakeServer();
+		when(fakeServer.getPlayer(fakePlayer.getName())).thenReturn(fakePlayer);
 		env.getEnv(CommandHelperEnvironment.class).SetPlayer(fakePlayer);
 	}
 
@@ -475,6 +476,15 @@ public void testClosure9() throws Exception {
 		verify(fakePlayer).sendMessage("{Hello World}");
 	}
 
+	@Test(timeout = 10000)
+	public void testClosure10() throws Exception {
+		SRun("@a = closure(msg('yes'));"
+				+ "@b = closure(msg('no'));"
+				+ "executeas('" + fakePlayer.getName() + "', null, @a);"
+				+ "execute(@b);", fakeServer.getConsole());
+		verify(fakePlayer).sendMessage("yes");
+	}
+
 	@Test(timeout = 10000)
 	public void testWhile() throws Exception {
 		SRun("assign(@i, 2) while(@i > 0, @i-- msg('hi'))", fakePlayer);