com.google.javascript.jscomp

Class StripCode.Strip

java.lang.Object

com.google.javascript.jscomp.NodeTraversal.AbstractPostOrderCallback

com.google.javascript.jscomp.StripCode.Strip

All Implemented Interfaces:

NodeTraversal.Callback

Enclosing class:

StripCode

private class StripCode.Strip
extends NodeTraversal.AbstractPostOrderCallback

A callback that strips debug code from a JavaScript parse tree.

Constructor Summary

Constructors

Modifier	Constructor and Description
private	Strip()

Method Summary

Modifier and Type	Method and Description
private boolean	actsOnStripType(NodeTraversal t, Node callNode) Determines whether the given node helps to define a strip type.
(package private) void	eliminateKeysWithStripNamesFromObjLit(NodeTraversal t, Node n) Eliminates any object literal keys in an object literal declaration that have strip names.
(package private) boolean	isCallWhoseReturnValueShouldBeStripped(Node n) Gets whether a node is a CALL node whose return value should be stripped.
(package private) boolean	isMethodOrCtorCallThatTriggersRemoval(NodeTraversal t, Node n, Node parent) Gets whether a CALL node triggers statement removal, based on the name of the object whose method is being called, or the name of the method.
(package private) boolean	isReferenceToRemovedVar(NodeTraversal t, Node n) Determines whether a NAME node represents a reference to a variable that has been removed.
(package private) boolean	isStripName(java.lang.String name) Gets whether a JavaScript identifier is the name of a variable or property that should be stripped.
(package private) void	maybeEliminateAssignmentByLvalueName(NodeTraversal t, Node n, Node parent) Eliminates an assignment if the l-value is: - A field name that's a strip name - A qualified name that begins with a strip type
(package private) void	maybeEliminateExpressionByName(NodeTraversal t, Node n, Node parent) Eliminates an expression if it refers to: - A field name that's a strip name - A qualified name that begins with a strip type This gets rid of construct like: a.prototype.logger; (used instead of a.prototype.logger = null;) This expression is not an assignment and so will not be caught by maybeEliminateAssignmentByLvalueName.
(package private) void	maybeRemoveCall(NodeTraversal t, Node n, Node parent) Removes a method call if isMethodOrCtorCallThatTriggersRemoval(com.google.javascript.jscomp.NodeTraversal, com.google.javascript.rhino.Node, com.google.javascript.rhino.Node) indicates that it should be removed.
(package private) void	maybeRemoveReferenceToRemovedVariable(NodeTraversal t, Node n, Node parent) Removes a reference if it is a reference to a removed variable.
(package private) boolean	nameIncludesFieldNameToStrip(Node n)
(package private) boolean	qualifiedNameBeginsWithStripType(Node n) Gets whether a qualified name begins with a strip name.
(package private) boolean	qualifiedNameBeginsWithStripType(java.lang.String name) Gets whether a qualified name begins with a strip name.
(package private) void	removeVarDeclarationsByNameOrRvalue(NodeTraversal t, Node n, Node parent) Removes declarations of any variables whose names are strip names or whose whose r-values are static method calls on strip types.
(package private) void	replaceHighestNestedCallWithNull(Node node, Node parent) Use a while loop to get up out of any nested calls.
(package private) void	replaceWithEmpty(Node n, Node parent) Replaces a node with an EMPTY node.
(package private) void	replaceWithNull(Node n, Node parent) Replaces a node with a NULL node.
void	visit(NodeTraversal t, Node n, Node parent) Visits a node in postorder (after its children have been visited).

Methods inherited from class com.google.javascript.jscomp.NodeTraversal.AbstractPostOrderCallback

shouldTraverse

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Strip

private Strip()

Method Detail

visit

public void visit(NodeTraversal t,
                  Node n,
                  Node parent)

Description copied from interface: NodeTraversal.Callback

Visits a node in postorder (after its children have been visited). A node is visited only if all its parents should be traversed (NodeTraversal.Callback.shouldTraverse(NodeTraversal, Node, Node)).

Implementations can have side effects (e.g. modifying the parse tree).

removeVarDeclarationsByNameOrRvalue

void removeVarDeclarationsByNameOrRvalue(NodeTraversal t,
                                         Node n,
                                         Node parent)

Removes declarations of any variables whose names are strip names or whose whose r-values are static method calls on strip types. Builds a set of removed variables so that all references to them can be removed.

Parameters:

t - The traversal

n - A VAR node

parent - n's parent

maybeRemoveReferenceToRemovedVariable

void maybeRemoveReferenceToRemovedVariable(NodeTraversal t,
                                           Node n,
                                           Node parent)

Removes a reference if it is a reference to a removed variable.

Parameters:

t - The traversal

n - A NAME node

parent - n's parent

replaceHighestNestedCallWithNull

void replaceHighestNestedCallWithNull(Node node,
                                      Node parent)

Use a while loop to get up out of any nested calls. For example, if we have just detected that we need to remove the a.b() call in a.b().c().d(), we'll have to remove all of the calls, and it will take a few iterations through this loop to get up to d().

maybeEliminateAssignmentByLvalueName

void maybeEliminateAssignmentByLvalueName(NodeTraversal t,
                                          Node n,
                                          Node parent)

Eliminates an assignment if the l-value is: - A field name that's a strip name - A qualified name that begins with a strip type

Parameters:

t - The traversal

n - An ASSIGN node

parent - n's parent

maybeEliminateExpressionByName

void maybeEliminateExpressionByName(NodeTraversal t,
                                    Node n,
                                    Node parent)

Eliminates an expression if it refers to: - A field name that's a strip name - A qualified name that begins with a strip type This gets rid of construct like: a.prototype.logger; (used instead of a.prototype.logger = null;) This expression is not an assignment and so will not be caught by maybeEliminateAssignmentByLvalueName.

Parameters:

t - The traversal

n - An EXPR_RESULT node

parent - n's parent

maybeRemoveCall

void maybeRemoveCall(NodeTraversal t,
                     Node n,
                     Node parent)

Removes a method call if isMethodOrCtorCallThatTriggersRemoval(com.google.javascript.jscomp.NodeTraversal, com.google.javascript.rhino.Node, com.google.javascript.rhino.Node) indicates that it should be removed.

Parameters:

t - The traversal

n - A CALL node

parent - n's parent

eliminateKeysWithStripNamesFromObjLit

void eliminateKeysWithStripNamesFromObjLit(NodeTraversal t,
                                           Node n)

Eliminates any object literal keys in an object literal declaration that have strip names.

Parameters:

t - The traversal

n - An OBJLIT node

isCallWhoseReturnValueShouldBeStripped

boolean isCallWhoseReturnValueShouldBeStripped(@Nullable
                                               Node n)

Gets whether a node is a CALL node whose return value should be stripped. A call's return value should be stripped if the function getting called is a static method in a class that gets stripped. For example, if "goog.debug.Logger" is a strip name, then this function returns true for a call such as "goog.debug.Logger.getLogger(...)". It may also simply be a function that is getting stripped. For example, if "getLogger" is a strip name, but not "goog.debug.Logger", this will still return true.

Parameters:

n - A node (typically a CALL node)

Returns:

Whether the call's return value should be stripped

qualifiedNameBeginsWithStripType

boolean qualifiedNameBeginsWithStripType(Node n)

Gets whether a qualified name begins with a strip name. The names "goog.debug", "goog.debug.Logger", and "goog.debug.Logger.Level" are examples of strip names that would result in this function returning true for a node representing the name "goog.debug.Logger.Level".

Parameters:

n - A node (typically a NAME or GETPROP node)

Returns:

Whether the name begins with a strip name

qualifiedNameBeginsWithStripType

boolean qualifiedNameBeginsWithStripType(java.lang.String name)

Gets whether a qualified name begins with a strip name. The names "goog.debug", "goog.debug.Logger", and "goog.debug.Logger.Level" are examples of strip names that would result in this function returning true for a node representing the name "goog.debug.Logger.Level".

Parameters:

name - A qualified class name

Returns:

Whether the name begins with a strip name

isReferenceToRemovedVar

boolean isReferenceToRemovedVar(NodeTraversal t,
                                Node n)

Determines whether a NAME node represents a reference to a variable that has been removed.

Parameters:

t - The traversal

n - A NAME node

Returns:

Whether the variable was removed

isMethodOrCtorCallThatTriggersRemoval

boolean isMethodOrCtorCallThatTriggersRemoval(NodeTraversal t,
                                              Node n,
                                              Node parent)

Gets whether a CALL node triggers statement removal, based on the name of the object whose method is being called, or the name of the method. Checks whether the name begins with a strip type, includes a field name that's a strip name, or belongs to the set of global class-defining functions (e.g. goog.inherits).

Parameters:

t - The traversal

n - A CALL node

Returns:

Whether the node triggers statement removal

nameIncludesFieldNameToStrip

boolean nameIncludesFieldNameToStrip(@Nullable
                                     Node n)

Returns:

Whether a name includes a field name that should be stripped. E.g., "foo.stripMe.bar", "(foo.bar).stripMe", etc.

actsOnStripType

private boolean actsOnStripType(NodeTraversal t,
                                Node callNode)

Determines whether the given node helps to define a strip type. For example, goog.inherits(stripType, Object) would be such a call. Also reports an error if a non-strip type inherits from a strip type.

Parameters:

t - The current traversal

callNode - The CALL node

isStripName

boolean isStripName(java.lang.String name)

Gets whether a JavaScript identifier is the name of a variable or property that should be stripped.

Parameters:

name - A JavaScript identifier

Returns:

Whether name is a name that triggers removal

replaceWithNull

void replaceWithNull(Node n,
                     Node parent)

Replaces a node with a NULL node. This is useful where a value is expected.

Parameters:

n - A node

parent - n's parent

replaceWithEmpty

void replaceWithEmpty(Node n,
                      Node parent)

Replaces a node with an EMPTY node. This is useful where a statement is expected.

Parameters:

n - A node

parent - n's parent