Send worker changes to master

bvm/ballerina-runtime/src/main/java/io/ballerina/runtime/internal/ErrorUtils.java

@@ -30,6 +30,7 @@
 import io.ballerina.runtime.internal.values.MapValueImpl;
 import io.ballerina.runtime.internal.values.MappingInitialValueEntry;
 
+import static io.ballerina.runtime.api.constants.RuntimeConstants.BALLERINA_LANG_ERROR_PKG_ID;
 import static io.ballerina.runtime.api.constants.RuntimeConstants.FLOAT_LANG_LIB;
 import static io.ballerina.runtime.api.creators.ErrorCreator.createError;
 import static io.ballerina.runtime.internal.errors.ErrorCodes.INCOMPATIBLE_CONVERT_OPERATION;
@@ -187,4 +188,11 @@ public static BError createInvalidFractionDigitsError() {
                 ErrorReasons.INVALID_FRACTION_DIGITS_ERROR),
                 ErrorHelper.getErrorDetails(ErrorCodes.INVALID_FRACTION_DIGITS));
     }
+
+    public static BError createNoMessageError(String chnlName) {
+        String[] splitWorkers = chnlName.split(":")[0].split("->");
+        return createError(BALLERINA_LANG_ERROR_PKG_ID, "NoMessage", ErrorReasons.NO_MESSAGE_ERROR,
+                null, ErrorHelper.getErrorDetails(ErrorCodes.NO_MESSAGE_ERROR,
+                        StringUtils.fromString(splitWorkers[0]), StringUtils.fromString(splitWorkers[1])));
+    }
 }

bvm/ballerina-runtime/src/main/java/io/ballerina/runtime/internal/errors/ErrorCodes.java

@@ -149,7 +149,8 @@ public enum ErrorCodes implements DiagnosticCode {
     REGEXP_INVALID_HEX_DIGIT("regexp.invalid.hex.digit", "RUNTIME_0120"),
     CONFIG_TOML_INVALID_MODULE_STRUCTURE_WITH_VARIABLE("config.toml.invalid.module.structure.with.variable",
                                                                "RUNTIME_0121"),
-    EMPTY_XML_SEQUENCE_HAS_NO_ATTRIBUTES("empty.xml.sequence.no.attributes", "RUNTIME_0122");
+    EMPTY_XML_SEQUENCE_HAS_NO_ATTRIBUTES("empty.xml.sequence.no.attributes", "RUNTIME_0122"),
+    NO_MESSAGE_ERROR("no.worker.message.received", "RUNTIME_0123");
 
     private final String errorMsgKey;
     private final String errorCode;

bvm/ballerina-runtime/src/main/java/io/ballerina/runtime/internal/errors/ErrorReasons.java

@@ -133,6 +133,8 @@ private ErrorReasons() {}
     public static final BString REGEXP_OPERATION_ERROR = getModulePrefixedReason(REGEXP_LANG_LIB,
             "RegularExpressionOperationError");
 
+    public static final BString NO_MESSAGE_ERROR = StringUtils.fromString("NoMessage");
+
     public static BString getModulePrefixedReason(String moduleName, String identifier) {
         return StringUtils.fromString(BALLERINA_ORG_PREFIX.concat(moduleName)
                                               .concat(CLOSING_CURLY_BRACE).concat(identifier));

bvm/ballerina-runtime/src/main/java/io/ballerina/runtime/internal/scheduling/Strand.java

@@ -23,6 +23,7 @@
 import io.ballerina.runtime.api.creators.ErrorCreator;
 import io.ballerina.runtime.api.utils.StringUtils;
 import io.ballerina.runtime.api.values.BError;
+import io.ballerina.runtime.api.values.BMap;
 import io.ballerina.runtime.api.values.BString;
 import io.ballerina.runtime.internal.TypeChecker;
 import io.ballerina.runtime.internal.values.ChannelDetails;
@@ -90,6 +91,8 @@ public class Strand {
     public Stack<TransactionLocalContext> trxContexts;
     private State state;
     private final ReentrantLock strandLock;
+    public BMap<BString, Object> workerReceiveMap = null;
+    public int channelCount = 0;
 
     public Strand(String name, StrandMetadata metadata, Scheduler scheduler, Strand parent,
                   Map<String, Object> properties) {

bvm/ballerina-runtime/src/main/java/io/ballerina/runtime/internal/scheduling/WDChannels.java

@@ -17,9 +17,22 @@
 */
 package io.ballerina.runtime.internal.scheduling;
 
+import io.ballerina.runtime.api.creators.ValueCreator;
+import io.ballerina.runtime.api.types.Type;
+import io.ballerina.runtime.api.utils.StringUtils;
+import io.ballerina.runtime.api.values.BMap;
+import io.ballerina.runtime.api.values.BString;
+import io.ballerina.runtime.internal.ErrorUtils;
+import io.ballerina.runtime.internal.values.ChannelDetails;
+import io.ballerina.runtime.internal.values.ErrorValue;
+
+import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
+import static io.ballerina.runtime.internal.scheduling.State.BLOCK_AND_YIELD;
+
 /**
  * This represents a worker data channel holder that is created for each strand to hold channels required.
  *
@@ -28,11 +41,13 @@
 public class WDChannels {
 
     private Map<String, WorkerDataChannel> wDChannels;
+    private final List<ErrorValue> errors = new ArrayList<>();
 
-    //TODO try to generalize this to a normal data channel, in that case we won't need these classes.
-    public WDChannels() {
+    // A worker receive field for multiple receive action.
+    public record ReceiveField(String fieldName, String channelName) {
     }
 
+    //TODO try to generalize this to a normal data channel, in that case we won't need these classes.
     public synchronized WorkerDataChannel getWorkerDataChannel(String name) {
         if (this.wDChannels == null) {
             this.wDChannels = new HashMap<>();
@@ -44,4 +59,122 @@ public synchronized WorkerDataChannel getWorkerDataChannel(String name) {
         }
         return channel;
     }
+
+    public Object receiveDataMultipleChannels(Strand strand, ReceiveField[] receiveFields, Type targetType)
+            throws Throwable {
+        if (strand.workerReceiveMap == null) {
+            strand.workerReceiveMap = ValueCreator.createMapValue(targetType);
+        }
+        for (ReceiveField field : receiveFields) {
+            WorkerDataChannel channel = getWorkerDataChannel(field.channelName());
+            WorkerDataChannel.State state = channel.getState();
+            Object result = null;
+            switch (state) {
+                case OPEN:
+                    result = channel.tryTakeData(strand, true);
+                    break;
+                case AUTO_CLOSED:
+                    result = ErrorUtils.createNoMessageError(field.channelName());
+                    break;
+                case CLOSED:
+                    continue;
+            }
+            checkAndPopulateResult(strand, field, result, channel);
+        }
+        return clearResultCache(strand, receiveFields);
+    }
+
+    private void checkAndPopulateResult(Strand strand, ReceiveField field, Object result, WorkerDataChannel channel) {
+        if (result == null) {
+            strand.setState(BLOCK_AND_YIELD);
+            return;
+        }
+        result = getResultValue(result);
+        strand.workerReceiveMap.populateInitialValue(StringUtils.fromString(field.fieldName()), result);
+        channel.close();
+        ++strand.channelCount;
+    }
+
+    private Object clearResultCache(Strand strand, ReceiveField[] receiveFields) {
+        if (strand.channelCount != receiveFields.length) {
+            return null;
+        }
+        BMap<BString, Object> map = strand.workerReceiveMap;
+        strand.workerReceiveMap = null;
+        strand.channelCount = 0;
+        strand.setState(State.RUNNABLE);
+        return map;
+    }
+
+    public Object receiveDataAlternateChannels(Strand strand, String[] channels) throws Throwable {
+        Object result = null;
+        boolean allChannelsClosed = true;
+        for (String channelName : channels) {
+            WorkerDataChannel channel = getWorkerDataChannel(channelName);
+            WorkerDataChannel.State state = channel.getState();
+            if (state == WorkerDataChannel.State.OPEN) {
+                allChannelsClosed = false;
+                result = handleResultForOpenChannel(strand, channels, channel);
+            } else if (state == WorkerDataChannel.State.AUTO_CLOSED) {
+                errors.add((ErrorValue) ErrorUtils.createNoMessageError(channelName));
+            }
+        }
+        return processResulAndError(strand, channels, result, allChannelsClosed);
+    }
+
+    private Object handleResultForOpenChannel(Strand strand, String[] channels, WorkerDataChannel channel)
+            throws Throwable {
+        Object result = channel.tryTakeData(strand, true);
+        if (result == null) {
+            return null;
+        }
+        Object resultValue = getResultValue(result);
+        if (resultValue instanceof ErrorValue errorValue) {
+            errors.add(errorValue);
+            channel.close();
+            return null;
+        }
+        closeChannels(channels);
+        return result;
+    }
+
+    private static Object getResultValue(Object result) {
+        if (result instanceof WorkerDataChannel.WorkerResult workerResult) {
+            return workerResult.value;
+        }
+        return result;
+    }
+
+    private Object processResulAndError(Strand strand, String[] channels, Object result, boolean allChannelsClosed) {
+        if (result == null) {
+            if (errors.size() == channels.length) {
+                result = errors.get(errors.size() - 1);
+            } else if (!allChannelsClosed) {
+                strand.setState(BLOCK_AND_YIELD);
+            }
+        } else {
+            strand.setState(State.RUNNABLE);
+        }
+        return getResultValue(result);
+    }
+
+    private void closeChannels(String[] channels) {
+        for (String channelName : channels) {
+            WorkerDataChannel channel = getWorkerDataChannel(channelName);
+            channel.close();
+            channel.callCount = 2;
+        }
+    }
+
+    public synchronized void removeCompletedChannels(Strand strand, String channelName) {
+        if (this.wDChannels != null) {
+            WorkerDataChannel channel = this.wDChannels.get(channelName);
+            // callCount is incremented to 2 when the message passing is completed.
+            if (channel != null && channel.callCount == 2) {
+                this.wDChannels.remove(channelName);
+                strand.channelDetails.remove(new ChannelDetails(channelName, true, false));
+            }
+        }
+    }
+
 }