Query Action implementation & related refactoring

compiler/ballerina-lang/spotbugs-exclude.xml

@@ -49,6 +49,9 @@
     <Match>
         <Package name="org.wso2.ballerinalang.compiler.tree.expressions" />
     </Match>
+    <Match>
+        <Package name="org.wso2.ballerinalang.compiler.tree.clauses" />
+    </Match>
     <Match>
         <Package name="org.wso2.ballerinalang.compiler.tree.statements" />
     </Match>

compiler/ballerina-lang/src/main/java/org/ballerinalang/model/TreeBuilder.java

@@ -17,6 +17,7 @@
  */
 package org.ballerinalang.model;
 
+import org.ballerinalang.model.clauses.DoClauseNode;
 import org.ballerinalang.model.clauses.FromClauseNode;
 import org.ballerinalang.model.clauses.SelectClauseNode;
 import org.ballerinalang.model.clauses.WhereClauseNode;
@@ -103,6 +104,7 @@
 import org.ballerinalang.model.tree.statements.MatchNode.MatchStructuredBindingPatternNode;
 import org.ballerinalang.model.tree.statements.MatchNode.MatchTypedBindingPatternNode;
 import org.ballerinalang.model.tree.statements.PanicNode;
+import org.ballerinalang.model.tree.statements.QueryActionNode;
 import org.ballerinalang.model.tree.statements.RecordDestructureNode;
 import org.ballerinalang.model.tree.statements.RetryNode;
 import org.ballerinalang.model.tree.statements.ReturnNode;
@@ -146,6 +148,7 @@
 import org.wso2.ballerinalang.compiler.tree.BLangTupleVariable;
 import org.wso2.ballerinalang.compiler.tree.BLangTypeDefinition;
 import org.wso2.ballerinalang.compiler.tree.BLangXMLNS;
+import org.wso2.ballerinalang.compiler.tree.clauses.BLangDoClause;
 import org.wso2.ballerinalang.compiler.tree.clauses.BLangFromClause;
 import org.wso2.ballerinalang.compiler.tree.clauses.BLangSelectClause;
 import org.wso2.ballerinalang.compiler.tree.clauses.BLangWhereClause;
@@ -222,6 +225,7 @@
 import org.wso2.ballerinalang.compiler.tree.statements.BLangMatch.BLangMatchStructuredBindingPatternClause;
 import org.wso2.ballerinalang.compiler.tree.statements.BLangMatch.BLangMatchTypedBindingPatternClause;
 import org.wso2.ballerinalang.compiler.tree.statements.BLangPanic;
+import org.wso2.ballerinalang.compiler.tree.statements.BLangQueryAction;
 import org.wso2.ballerinalang.compiler.tree.statements.BLangRecordDestructure;
 import org.wso2.ballerinalang.compiler.tree.statements.BLangRecordVariableDef;
 import org.wso2.ballerinalang.compiler.tree.statements.BLangRetry;
@@ -647,6 +651,14 @@ public static SelectClauseNode createSelectClauseNode() {
         return new BLangSelectClause();
     }
 
+    public static DoClauseNode createDoClauseNode() {
+        return new BLangDoClause();
+    }
+
+    public static QueryActionNode createQueryActionStatementNode() {
+        return new BLangQueryAction();
+    }
+
     public static WhereClauseNode createWhereClauseNode() {
         return new BLangWhereClause();
     }

compiler/ballerina-lang/src/main/java/org/ballerinalang/model/clauses/DoClauseNode.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2020, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
+ *
+ * WSO2 Inc. licenses this file to you 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.
+ */
+package org.ballerinalang.model.clauses;
+
+import org.ballerinalang.model.tree.Node;
+import org.ballerinalang.model.tree.statements.BlockNode;
+
+/**
+ * The interface with the APIs to implement the "do" clause.
+ *
+ * @since 1.2.0
+ */
+public interface DoClauseNode extends Node {
+
+    BlockNode getBody();
+
+    void setBody(BlockNode body);
+}

compiler/ballerina-lang/src/main/java/org/ballerinalang/model/tree/NodeKind.java

@@ -150,11 +150,13 @@ public enum NodeKind {
     COMPENSATE,
     CHANNEL_RECEIVE,
     CHANNEL_SEND,
+    DO_ACTION,
 
     /* Clauses */
     SELECT,
     FROM,
     WHERE,
+    DO,
 
     /* Types */
     ARRAY_TYPE,

compiler/ballerina-lang/src/main/java/org/ballerinalang/model/tree/statements/QueryActionNode.java

@@ -0,0 +1,44 @@
+/*
+ *  Copyright (c) 2020, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
+ *
+ *  WSO2 Inc. licenses this file to you 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.
+ */
+package org.ballerinalang.model.tree.statements;
+
+import org.ballerinalang.model.clauses.DoClauseNode;
+import org.ballerinalang.model.clauses.FromClauseNode;
+import org.ballerinalang.model.clauses.WhereClauseNode;
+
+import java.util.List;
+
+/**
+ * Represents the DoAction statement node.
+ *
+ * @since 1.2.0
+ */
+public interface QueryActionNode extends StatementNode {
+
+    List<? extends FromClauseNode> getFromClauseNodes();
+
+    void addFromClauseNode(FromClauseNode fromClauseNode);
+
+    List<? extends WhereClauseNode> getWhereClauseNode();
+
+    void addWhereClauseNode(WhereClauseNode whereClauseNode);
+
+    DoClauseNode getDoClauseNode();
+
+    void setDoClauseNode(DoClauseNode doClauseNode);
+}

compiler/ballerina-lang/src/main/java/org/wso2/ballerinalang/compiler/desugar/Desugar.java

@@ -84,9 +84,6 @@
 import org.wso2.ballerinalang.compiler.tree.BLangXMLNS;
 import org.wso2.ballerinalang.compiler.tree.BLangXMLNS.BLangLocalXMLNS;
 import org.wso2.ballerinalang.compiler.tree.BLangXMLNS.BLangPackageXMLNS;
-import org.wso2.ballerinalang.compiler.tree.clauses.BLangFromClause;
-import org.wso2.ballerinalang.compiler.tree.clauses.BLangSelectClause;
-import org.wso2.ballerinalang.compiler.tree.clauses.BLangWhereClause;
 import org.wso2.ballerinalang.compiler.tree.expressions.BLangAccessExpression;
 import org.wso2.ballerinalang.compiler.tree.expressions.BLangAnnotAccessExpr;
 import org.wso2.ballerinalang.compiler.tree.expressions.BLangArrowFunction;
@@ -186,6 +183,7 @@
 import org.wso2.ballerinalang.compiler.tree.statements.BLangMatch.BLangMatchStructuredBindingPatternClause;
 import org.wso2.ballerinalang.compiler.tree.statements.BLangMatch.BLangMatchTypedBindingPatternClause;
 import org.wso2.ballerinalang.compiler.tree.statements.BLangPanic;
+import org.wso2.ballerinalang.compiler.tree.statements.BLangQueryAction;
 import org.wso2.ballerinalang.compiler.tree.statements.BLangRecordDestructure;
 import org.wso2.ballerinalang.compiler.tree.statements.BLangRecordVariableDef;
 import org.wso2.ballerinalang.compiler.tree.statements.BLangRetry;
@@ -260,6 +258,7 @@ public class Desugar extends BLangNodeVisitor {
     private SymbolResolver symResolver;
     private final SymbolEnter symbolEnter;
     private ClosureDesugar closureDesugar;
+    private QueryDesugar queryDesugar;
     private AnnotationDesugar annotationDesugar;
     private Types types;
     private Names names;
@@ -304,6 +303,7 @@ private Desugar(CompilerContext context) {
         this.symResolver = SymbolResolver.getInstance(context);
         this.symbolEnter = SymbolEnter.getInstance(context);
         this.closureDesugar = ClosureDesugar.getInstance(context);
+        this.queryDesugar = QueryDesugar.getInstance(context);
         this.annotationDesugar = AnnotationDesugar.getInstance(context);
         this.types = Types.getInstance(context);
         this.names = Names.getInstance(context);
@@ -4317,135 +4317,15 @@ public void visit(BLangStatementExpression bLangStatementExpression) {
 
     @Override
     public void visit(BLangQueryExpr queryExpr) {
-        List<BLangFromClause> fromClauseList = queryExpr.fromClauseList;
-        BLangFromClause fromClause = fromClauseList.get(0);
-        BLangSelectClause selectClause = queryExpr.selectClause;
-        List<BLangWhereClause> whereClauseList = queryExpr.whereClauseList;
-        DiagnosticPos pos = fromClause.pos;
-
-        // Create Foreach statement
-        //
-        // Below query expression :
-        //      from var person in personList
-        //
-        // changes as,
-        //      foreach var person in personList {
-        //          ....
-        //      }
-
-        BLangForeach leafForEach = null;
-        BLangForeach parentForEach = null;
-
-        for (BLangFromClause bLangFromClause : fromClauseList) {
-            BLangForeach foreach = (BLangForeach) TreeBuilder.createForeachNode();
-            foreach.pos = queryExpr.pos;
-            foreach.collection = bLangFromClause.collection;
-            types.setForeachTypedBindingPatternType(foreach);
-
-            foreach.variableDefinitionNode = bLangFromClause.variableDefinitionNode;
-            foreach.isDeclaredWithVar = fromClause.isDeclaredWithVar;
-
-            if (leafForEach != null) {
-                BLangBlockStmt foreachBody = ASTBuilderUtil.createBlockStmt(pos);
-                foreachBody.addStatement(foreach);
-                leafForEach.setBody(foreachBody);
-            } else {
-                parentForEach = foreach;
-            }
-
-            leafForEach = foreach;
-        }
-
-        BLangBlockStmt foreachBody = ASTBuilderUtil.createBlockStmt(pos);
-
-        BType outputArrayType;
-        if (selectClause.expression  != null && selectClause.expression.type != null) {
-            outputArrayType = new BArrayType(selectClause.expression.type);
-        } else {
-            outputArrayType = fromClause.varType;
-        }
-
-        BLangListConstructorExpr emptyArrayExpr = ASTBuilderUtil.createEmptyArrayLiteral(pos,
-                (BArrayType) outputArrayType);
-        BVarSymbol emptyArrayVarSymbol = new BVarSymbol(0, new Name("$outputDataArray$"),
-                this.env.scope.owner.pkgID, outputArrayType, env.scope.owner);
-        BLangSimpleVariable outputArrayVariable =
-                ASTBuilderUtil.createVariable(pos, "$outputDataArray$", outputArrayType,
-                        emptyArrayExpr, emptyArrayVarSymbol);
-
-        // Create temp array variable
-        //      Person[] x = [];
-
-        BLangSimpleVariableDef outputVariableDef =
-                ASTBuilderUtil.createVariableDef(pos, outputArrayVariable);
-        BLangSimpleVarRef outputVarRef = ASTBuilderUtil.createVariableRef(pos, outputArrayVariable.symbol);
-
-        // Create indexed based access expression statement
-        //      x[x.length()] = {
-        //         firstName: person.firstName,
-        //         lastName: person.lastName
-        //      };
-
-        if (selectClause.expression.type == null) {
-            selectClause.expression.type = fromClause.varType;
-        }
-
-        BLangInvocation lengthInvocation = createLengthInvocation(pos, outputArrayVariable.symbol);
-        lengthInvocation.expr = outputVarRef;
-        BLangIndexBasedAccess indexAccessExpr = ASTBuilderUtil.createIndexAccessExpr(outputVarRef, lengthInvocation);
-        indexAccessExpr.type = selectClause.expression.type;
-
-        BLangAssignment outputVarAssignment = ASTBuilderUtil.createAssignmentStmt(pos, indexAccessExpr,
-                selectClause.expression);
-        // Set the indexed based access expression statement as foreach body
-        foreachBody.addStatement(outputVarAssignment);
-
-        if (whereClauseList.size() > 0) {
-            // Create If Statement with Where expression and foreach body
-            BLangIf outerIf = null;
-            BLangIf innerIf = null;
-            for (BLangWhereClause whereClause : whereClauseList) {
-                BLangIf bLangIf = (BLangIf) TreeBuilder.createIfElseStatementNode();
-                bLangIf.pos = queryExpr.pos;
-                bLangIf.expr = whereClause.expression;
-                if (innerIf != null) {
-                    BLangBlockStmt bLangBlockStmt = ASTBuilderUtil.createBlockStmt(pos);
-                    bLangBlockStmt.addStatement(bLangIf);
-                    innerIf.setBody(bLangBlockStmt);
-                } else {
-                    outerIf = bLangIf;
-                }
-                innerIf = bLangIf;
-            }
-            innerIf.setBody(foreachBody);
-            BLangBlockStmt bLangBlockStmt = ASTBuilderUtil.createBlockStmt(pos);
-            bLangBlockStmt.addStatement(outerIf);
-            leafForEach.setBody(bLangBlockStmt);
-        } else {
-            leafForEach.setBody(foreachBody);
-        }
-
-        // Create block statement with temp variable definition statement & foreach statement
-        BLangBlockStmt blockStmt = ASTBuilderUtil.createBlockStmt(pos);
-        blockStmt.addStatement(outputVariableDef);
-        blockStmt.addStatement(parentForEach);
-        BLangStatementExpression stmtExpr = ASTBuilderUtil.createStatementExpression(blockStmt, outputVarRef);
-
-        stmtExpr.type = outputArrayType;
+        BLangStatementExpression stmtExpr = queryDesugar.desugarQueryExpr(queryExpr, env);
         result = rewrite(stmtExpr, env);
     }
 
-
-    private BLangInvocation createLengthInvocation(DiagnosticPos pos, BVarSymbol collectionSymbol) {
-        BInvokableSymbol lengthInvokableSymbol =
-                (BInvokableSymbol) symResolver.lookupLangLibMethod(collectionSymbol.type,
-                        names.fromString("length"));
-        BLangSimpleVarRef collection = ASTBuilderUtil.createVariableRef(pos, collectionSymbol);
-        BLangInvocation lengthInvocation = ASTBuilderUtil.createInvocationExprForMethod(pos, lengthInvokableSymbol,
-                Lists.of(collection), symResolver);
-        lengthInvocation.type = lengthInvokableSymbol.type.getReturnType();
-        // Note: No need to set lengthInvocation.expr for langLib functions as they are in requiredArgs
-        return lengthInvocation;
+    @Override
+    public void visit(BLangQueryAction queryAction) {
+        BLangBlockStmt blockStmt = queryDesugar.desugarQueryAction(queryAction, env);
+        rewrite(blockStmt, this.env);
+        result = blockStmt;
     }
 
     @Override