Class NodeTraversal.AbstractCfgCallback
- java.lang.Object
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- com.google.javascript.jscomp.NodeTraversal.AbstractCfgCallback
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- All Implemented Interfaces:
NodeTraversal.Callback
,NodeTraversal.ScopedCallback
- Direct Known Subclasses:
BranchCoverageInstrumentationCallback
- Enclosing class:
- NodeTraversal
public abstract static class NodeTraversal.AbstractCfgCallback extends java.lang.Object implements NodeTraversal.ScopedCallback
An traversal base class that tracks and caches the ControlFlowGraph (CFG) during the traversal. The CFGs are constructed lazily.
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Constructor Summary
Constructors Constructor Description AbstractCfgCallback()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
enterScope(NodeTraversal t)
Called immediately after entering a new scope.void
enterScopeWithCfg(NodeTraversal t)
void
exitScope(NodeTraversal t)
Called immediately before exiting a scope.void
exitScopeWithCfg(NodeTraversal t)
ControlFlowGraph<Node>
getControlFlowGraph(AbstractCompiler compiler)
Gets the control flow graph for the current JS scope.boolean
shouldTraverse(NodeTraversal t, Node n, Node parent)
Visits a node in preorder (before its children) and decides whether the node and its children should be traversed.void
visit(NodeTraversal t, Node n, Node parent)
Visits a node in postorder (after its children).
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Method Detail
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getControlFlowGraph
public ControlFlowGraph<Node> getControlFlowGraph(AbstractCompiler compiler)
Gets the control flow graph for the current JS scope.
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enterScope
public final void enterScope(NodeTraversal t)
Description copied from interface:NodeTraversal.ScopedCallback
Called immediately after entering a new scope. The new scope can be accessed through t.getScope()- Specified by:
enterScope
in interfaceNodeTraversal.ScopedCallback
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exitScope
public final void exitScope(NodeTraversal t)
Description copied from interface:NodeTraversal.ScopedCallback
Called immediately before exiting a scope. The ending scope can be accessed through t.getScope()- Specified by:
exitScope
in interfaceNodeTraversal.ScopedCallback
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enterScopeWithCfg
public void enterScopeWithCfg(NodeTraversal t)
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exitScopeWithCfg
public void exitScopeWithCfg(NodeTraversal t)
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shouldTraverse
public boolean shouldTraverse(NodeTraversal t, Node n, Node parent)
Description copied from interface:NodeTraversal.Callback
Visits a node in preorder (before its children) and decides whether the node and its children should be traversed.If this method returns true, the node will be visited by
NodeTraversal.Callback.visit(NodeTraversal, Node, Node)
in postorder and its children will be visited by bothNodeTraversal.Callback.shouldTraverse(NodeTraversal, Node, Node)
in preorder and byNodeTraversal.Callback.visit(NodeTraversal, Node, Node)
in postorder.If this method returns false, the node will not be visited by
NodeTraversal.Callback.visit(NodeTraversal, Node, Node)
and its children will neither be visited byNodeTraversal.Callback.shouldTraverse(NodeTraversal, Node, Node)
norNodeTraversal.Callback.visit(NodeTraversal, Node, Node)
.Siblings are always visited left-to-right.
Implementations can have side-effects (e.g. modify the parse tree). Removing the current node is legal, but removing or reordering nodes above the current node may cause nodes to be visited twice or not at all.
- Specified by:
shouldTraverse
in interfaceNodeTraversal.Callback
- Parameters:
t
- The current traversal.n
- The current node.parent
- The parent of the current node.- Returns:
- whether the children of this node should be visited
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visit
public void visit(NodeTraversal t, Node n, Node parent)
Description copied from interface:NodeTraversal.Callback
Visits a node in postorder (after its children). A node is visited in postorder iffNodeTraversal.Callback.shouldTraverse(NodeTraversal, Node, Node)
returned true for its parent and itself. In particular, the root node is never visited in postorder.Siblings are always visited left-to-right.
Implementations can have side-effects (e.g. modify the parse tree). Removing the current node is legal, but removing or reordering nodes above the current node may cause nodes to be visited twice or not at all.
- Specified by:
visit
in interfaceNodeTraversal.Callback
- Parameters:
t
- The current traversal.n
- The current node.parent
- The parent of the current node.
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