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A small no-op refactoring of Es6RewriteGenerator.
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-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=188533564
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@SergejSalnikov @blickly
SergejSalnikov authored and blickly committed Mar 12, 2018
1 parent aa368ec commit d8aaa67
Showing 1 changed file with 30 additions and 37 deletions.
67 changes: 30 additions & 37 deletions src/com/google/javascript/jscomp/Es6RewriteGenerators.java
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Expand Up @@ -209,7 +209,7 @@ private class SingleGeneratorFunctionTranspiler {
SingleGeneratorFunctionTranspiler(Node genFunc, int genaratorNestingLevel) {
this.generatorNestingLevel = genaratorNestingLevel;
this.originalGeneratorBody = genFunc.getLastChild();
this.context = new TranspilationContext(originalGeneratorBody);
this.context = new TranspilationContext();
}

public void transpile() {
Expand Down Expand Up @@ -250,7 +250,7 @@ public void transpile() {
// once, which messes up its understanding of the types assigned to variables
// within it.
IR.doNode( // TODO(skill): Remove do-while loop when this pass moves after
// type checking or when OTI is fixed to handle this correctly.
// type checking or when OTI is fixed to handle this correctly.
IR.block(switchNode),
IR.number(0))));

Expand All @@ -275,8 +275,7 @@ public void transpile() {
IR.call(
IR.getprop(IR.name("$jscomp"), "generator", "createGenerator"),
genFuncName.cloneNode(),
program)))
.useSourceInfoFromForTree(genFunc);
program)).useSourceInfoFromForTree(originalGeneratorBody));

// Newly introduced functions have to be reported immediately.
compiler.reportChangeToChangeScope(program);
Expand Down Expand Up @@ -953,7 +952,6 @@ class SwitchCase {

// Allocate a new case
TranspilationContext.Case generatedCase = context.createCase();
generatedCase.caseNode.useSourceInfoFrom(caseSection);
generatedCase.caseBlock.useSourceInfoFrom(body);

// Replace old body with a jump instruction.
Expand Down Expand Up @@ -1048,13 +1046,12 @@ private class TranspilationContext {
boolean thisReferenceFound;
boolean argumentsReferenceFound;

TranspilationContext(Node sourceNode) {
programEndCase = new Case(IR.caseNode(IR.number(0), IR.block()));

currentCase =
new Case(IR.caseNode(IR.number(1), IR.block()).useSourceInfoFromForTree(sourceNode));
TranspilationContext() {
programEndCase = new Case();
checkState(programEndCase.id == 0);
currentCase = new Case();
checkState(currentCase.id == 1);
allCases.add(currentCase);
caseIdCounter = 1;
}

/**
Expand Down Expand Up @@ -1146,7 +1143,7 @@ void optimizeCaseIds() {
checkState(currentCase.jumpTo == null);
// Cases can be embedded only if they are referenced once and don't fall through.
if (currentCase.references.size() == 1 && !currentCase.mayFallThrough) {
currentCase.embedInto.replaceWith(currentCase.caseBlock.detach());
currentCase.embedInto.replaceWith(currentCase.caseBlock);
it.remove();
continue;
}
Expand Down Expand Up @@ -1191,7 +1188,7 @@ public void finalizeTransformation(Node switchNode) {
optimizeCaseIds();
// Write all state machine cases
for (Case currentCase : allCases) {
switchNode.addChildToBack(currentCase.caseNode);
switchNode.addChildToBack(currentCase.createCaseNode());
}
allCases.clear();
}
Expand All @@ -1204,6 +1201,7 @@ public void checkStateIsEmpty() {
checkState(catchCases.isEmpty());
checkState(finallyCases.isEmpty());
checkState(nestedFinallyBlockCount == 0);
checkState(allCases.isEmpty());
}

/** Adds a block of original code to the end of the current case. */
Expand All @@ -1221,6 +1219,13 @@ void writeGeneratedNode(Node n) {
currentCase.addNode(n);
}

/** Adds a new generated node to the end of the current case and finializes it. */
void writeGeneratedNodeAndBreak(Node n) {
writeGeneratedNode(n);
writeGeneratedNode(IR.breakNode().useSourceInfoFrom(n));
currentCase.mayFallThrough = false;
}

/** Creates a new detached case statement. */
Case createCase() {
return new Case();
Expand Down Expand Up @@ -1313,11 +1318,9 @@ void replaceBreakContinueWithJump(Node sourceNode, Case section, int breakSuppre
}
if (breakSuppressors == 0) {
// continue; => $context.jumpTo(x); break;
sourceNode
.getParent()
.addChildBefore(
callContextMethodResult(sourceNode, jumpMethod, section.getNumber(sourceNode)),
sourceNode);
sourceNode.getParent().addChildBefore(
callContextMethodResult(sourceNode, jumpMethod, section.getNumber(sourceNode)),
sourceNode);
sourceNode.replaceWith(IR.breakNode());
} else {
// "break;" inside a loop or swtich statement:
Expand Down Expand Up @@ -1453,10 +1456,8 @@ void leaveTryBlock(@Nullable Case catchCase, Case endCase, Node sourceNode) {
if (nextCatchCase != null) {
args.add(nextCatchCase.getNumber(sourceNode));
}
writeGeneratedNode(
writeGeneratedNodeAndBreak(
callContextMethodResult(sourceNode, "leaveTryBlock", args.toArray(new Node[0])));
writeGeneratedNode(IR.breakNode().useSourceInfoFrom(sourceNode));
currentCase.mayFallThrough = false;
}

/** Writes a statement Node that should be placed at the beginning of catch block. */
Expand Down Expand Up @@ -1541,10 +1542,8 @@ void leaveFinallyBlock(Case endCase, Node sourceNode) {
args.add(IR.number(nestedFinallyBlockCount).useSourceInfoFrom(sourceNode));
}

writeGeneratedNode(
writeGeneratedNodeAndBreak(
callContextMethodResult(sourceNode, "leaveFinallyBlock", args.toArray(new Node[0])));
writeGeneratedNode(IR.breakNode().useSourceInfoFrom(sourceNode));
currentCase.mayFallThrough = false;
}

/** Changes the {@link #currentCase} to a new one. */
Expand Down Expand Up @@ -1598,7 +1597,6 @@ public void popBreakContinueContext() {
/** A case section in a switch block of generator program. */
private class Case {
final int id;
final Node caseNode;
final Node caseBlock;

/**
Expand Down Expand Up @@ -1644,20 +1642,15 @@ private class Case {
/** Tells whether this case might fall-through. */
boolean mayFallThrough = true;

/** Creates a Case object for an already created case node. */
Case(Node caseNode) {
checkState(caseNode.isCase());
this.id = NodeUtil.getNumberValue(caseNode.getFirstChild()).intValue();
this.caseNode = caseNode;
this.caseBlock = caseNode.getLastChild();
}

/** Creates a new empty case section and assings a new id. */
Case() {
id = ++caseIdCounter;
caseNode =
IR.caseNode(IR.number(id), caseBlock = IR.block())
.useSourceInfoFromForTree(originalGeneratorBody);
this.id = caseIdCounter++;
this.caseBlock = IR.block().useSourceInfoFrom(originalGeneratorBody);
}

Node createCaseNode() {
return IR.caseNode(IR.number(id).useSourceInfoFrom(caseBlock), caseBlock)
.useSourceInfoFrom(caseBlock);
}

/** Returns the number node of the case section and increments a reference counter. */
Expand Down

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