/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed 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.apache.harmony.luni.lang.reflect;
import java.lang.reflect.Constructor;
import java.lang.reflect.GenericDeclaration;
import java.lang.reflect.GenericSignatureFormatError;
import java.lang.reflect.Method;
import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
/**
* Implements a parser for the generics signature attribute.
* Uses a top-down, resursive descent parsing approach for the following grammar:
* <pre>
* ClassSignature ::=
* OptFormalTypeParams SuperclassSignature {SuperinterfaceSignature}.
* SuperclassSignature ::= ClassTypeSignature.
* SuperinterfaceSignature ::= ClassTypeSignature.
*
* OptFormalTypeParams ::=
* ["<" FormalTypeParameter {FormalTypeParameter} ">"].
*
* FormalTypeParameter ::= Ident ClassBound {InterfaceBound}.
* ClassBound ::= ":" [FieldTypeSignature].
* InterfaceBound ::= ":" FieldTypeSignature.
*
* FieldTypeSignature ::=
* ClassTypeSignature | ArrayTypeSignature | TypeVariableSignature.
* ArrayTypeSignature ::= "[" TypSignature.
*
* ClassTypeSignature ::=
* "L" {Ident "/"} Ident OptTypeArguments {"." Ident OptTypeArguments} ";".
*
* OptTypeArguments ::= "<" TypeArgument {TypeArgument} ">".
*
* TypeArgument ::= ([WildcardIndicator] FieldTypeSignature) | "*".
* WildcardIndicator ::= "+" | "-".
*
* TypeVariableSignature ::= "T" Ident ";".
*
* TypSignature ::= FieldTypeSignature | BaseType.
* BaseType ::= "B" | "C" | "D" | "F" | "I" | "J" | "S" | "Z".
*
* MethodTypeSignature ::=
* OptFormalTypeParams "(" {TypeSignature} ")" ReturnType {ThrowsSignature}.
* ThrowsSignature ::= ("^" ClassTypeSignature) | ("^" TypeVariableSignature).
*
* ReturnType ::= TypSignature | VoidDescriptor.
* VoidDescriptor ::= "V".
* </pre>
*/
public class GenericSignatureParser {
public ListOfTypes exceptionTypes;
public ListOfTypes parameterTypes;
public TypeVariable[] formalTypeParameters;
public Type returnType;
public Type fieldType;
public ListOfTypes interfaceTypes;
public Type superclassType;
public ClassLoader loader;
GenericDeclaration genericDecl;
/*
* Parser:
*/
char symbol; // 0: eof; else valid term symbol or first char of identifier.
String identifier;
/*
* Scanner:
* eof is private to the scan methods
* and it's set only when a scan is issued at the end of the buffer.
*/
private boolean eof;
char[] buffer;
int pos;
public GenericSignatureParser(ClassLoader loader) {
this.loader = loader;
}
void setInput(GenericDeclaration genericDecl, String input) {
if (input != null) {
this.genericDecl = genericDecl;
this.buffer = input.toCharArray();
this.eof = false;
scanSymbol();
}
else {
this.eof = true;
}
}
/**
* Parses the generic signature of a class and creates the data structure
* representing the signature.
*
* @param genericDecl the GenericDeclaration calling this method
* @param signature the generic signature of the class
*/
public void parseForClass(GenericDeclaration genericDecl,
String signature) {
setInput(genericDecl, signature);
if (!eof) {
parseClassSignature();
} else {
if(genericDecl instanceof Class) {
Class c = (Class) genericDecl;
this.formalTypeParameters = ListOfVariables.empty;
this.superclassType = c.getSuperclass();
this.interfaceTypes = new ListOfTypes(c.getInterfaces());
} else {
this.formalTypeParameters = ListOfVariables.empty;
this.superclassType = Object.class;
this.interfaceTypes = ListOfTypes.empty;
}
}
}
/**
* Parses the generic signature of a method and creates the data structure
* representing the signature.
*
* @param genericDecl the GenericDeclaration calling this method
* @param signature the generic signature of the class
*/
public void parseForMethod(GenericDeclaration genericDecl,
String signature) {
setInput(genericDecl, signature);
if (!eof) {
parseMethodTypeSignature();
} else {
if(genericDecl instanceof Method) {
Method m = (Method) genericDecl;
this.formalTypeParameters = ListOfVariables.empty;
this.parameterTypes = new ListOfTypes(m.getParameterTypes());
this.exceptionTypes = new ListOfTypes(m.getExceptionTypes());
this.returnType = m.getReturnType();
} else {
this.formalTypeParameters = ListOfVariables.empty;
this.parameterTypes = ListOfTypes.empty;
this.exceptionTypes = ListOfTypes.empty;
this.returnType = void.class;
}
}
}
/**
* Parses the generic signature of a constructor and creates the data
* structure representing the signature.
*
* @param genericDecl the GenericDeclaration calling this method
* @param signature the generic signature of the class
*/
public void parseForConstructor(GenericDeclaration genericDecl,
String signature) {
setInput(genericDecl, signature);
if (!eof) {
parseMethodTypeSignature();
} else {
if(genericDecl instanceof Constructor) {
Constructor c = (Constructor) genericDecl;
this.formalTypeParameters = ListOfVariables.empty;
this.parameterTypes = new ListOfTypes(c.getParameterTypes());
this.exceptionTypes = new ListOfTypes(c.getExceptionTypes());
} else {
this.formalTypeParameters = ListOfVariables.empty;
this.parameterTypes = ListOfTypes.empty;
this.exceptionTypes = ListOfTypes.empty;
}
}
}
/**
* Parses the generic signature of a field and creates the data structure
* representing the signature.
*
* @param genericDecl the GenericDeclaration calling this method
* @param signature the generic signature of the class
*/
public void parseForField(GenericDeclaration genericDecl,
String signature) {
setInput(genericDecl, signature);
if (!eof) {
this.fieldType = parseFieldTypeSignature();
}
}
//
// Parser:
//
void parseClassSignature() {
// ClassSignature ::=
// OptFormalTypeParameters SuperclassSignature {SuperinterfaceSignature}.
parseOptFormalTypeParameters();
// SuperclassSignature ::= ClassTypeSignature.
this.superclassType = parseClassTypeSignature();
interfaceTypes = new ListOfTypes(16);
while (symbol > 0) {
// SuperinterfaceSignature ::= ClassTypeSignature.
interfaceTypes.add(parseClassTypeSignature());
}
}
void parseOptFormalTypeParameters() {
// OptFormalTypeParameters ::=
// ["<" FormalTypeParameter {FormalTypeParameter} ">"].
ListOfVariables typeParams = new ListOfVariables();
if (symbol == '<') {
scanSymbol();
typeParams.add(parseFormalTypeParameter());
while ((symbol != '>') && (symbol > 0)) {
typeParams.add(parseFormalTypeParameter());
}
expect('>');
}
this.formalTypeParameters = typeParams.getArray();
}
ImplForVariable<GenericDeclaration> parseFormalTypeParameter() {
// FormalTypeParameter ::= Ident ClassBound {InterfaceBound}.
scanIdentifier();
String name = identifier.intern(); // FIXME: is this o.k.?
ListOfTypes bounds = new ListOfTypes(8);
// ClassBound ::= ":" [FieldTypeSignature].
expect(':');
if (symbol == 'L' || symbol == '[' || symbol == 'T') {
bounds.add(parseFieldTypeSignature());
}
while (symbol == ':') {
// InterfaceBound ::= ":" FieldTypeSignature.
scanSymbol();
bounds.add(parseFieldTypeSignature());
}
return new ImplForVariable<GenericDeclaration>(genericDecl, name, bounds);
}
Type parseFieldTypeSignature() {
// FieldTypeSignature ::= ClassTypeSignature | ArrayTypeSignature
// | TypeVariableSignature.
switch (symbol) {
case 'L':
return parseClassTypeSignature();
case '[':
// ArrayTypeSignature ::= "[" TypSignature.
scanSymbol();
return new ImplForArray(parseTypeSignature());
case 'T':
return parseTypeVariableSignature();
default:
throw new GenericSignatureFormatError();
}
}
Type parseClassTypeSignature() {
// ClassTypeSignature ::= "L" {Ident "/"} Ident
// OptTypeArguments {"." Ident OptTypeArguments} ";".
expect('L');
StringBuilder qualIdent = new StringBuilder();
scanIdentifier();
while (symbol == '/') {
scanSymbol();
qualIdent.append(identifier).append(".");
scanIdentifier();
}
qualIdent.append(this.identifier);
ListOfTypes typeArgs = parseOptTypeArguments();
ImplForType parentType =
new ImplForType(null, qualIdent.toString(), typeArgs, loader);
ImplForType type = parentType;
while (symbol == '.') {
// Deal with Member Classes:
scanSymbol();
scanIdentifier();
qualIdent.append("$").append(identifier); // FIXME: is "$" correct?
typeArgs = parseOptTypeArguments();
type = new ImplForType(parentType, qualIdent.toString(), typeArgs,
loader);
}
expect(';');
return type;
}
ListOfTypes parseOptTypeArguments() {
// OptTypeArguments ::= "<" TypeArgument {TypeArgument} ">".
ListOfTypes typeArgs = new ListOfTypes(8);
if (symbol == '<') {
scanSymbol();
typeArgs.add(parseTypeArgument());
while ((symbol != '>') && (symbol > 0)) {
typeArgs.add(parseTypeArgument());
}
expect('>');
}
return typeArgs;
}
Type parseTypeArgument() {
// TypeArgument ::= (["+" | "-"] FieldTypeSignature) | "*".
ListOfTypes extendsBound = new ListOfTypes(1);
ListOfTypes superBound = new ListOfTypes(1);
if (symbol == '*') {
scanSymbol();
extendsBound.add(Object.class);
return new ImplForWildcard(extendsBound, superBound);
}
else if (symbol == '+') {
scanSymbol();
extendsBound.add(parseFieldTypeSignature());
return new ImplForWildcard(extendsBound, superBound);
}
else if (symbol == '-') {
scanSymbol();
superBound.add(parseFieldTypeSignature());
extendsBound.add(Object.class);
return new ImplForWildcard(extendsBound, superBound);
}
else {
return parseFieldTypeSignature();
}
}
ImplForVariable<GenericDeclaration> parseTypeVariableSignature() {
// TypeVariableSignature ::= "T" Ident ";".
expect('T');
scanIdentifier();
expect(';');
// Reference to type variable:
// Note: we don't know the declaring GenericDeclaration yet.
return new ImplForVariable<GenericDeclaration>(genericDecl, identifier);
}
Type parseTypeSignature() {
switch (symbol) {
case 'B': scanSymbol(); return byte.class;
case 'C': scanSymbol(); return char.class;
case 'D': scanSymbol(); return double.class;
case 'F': scanSymbol(); return float.class;
case 'I': scanSymbol(); return int.class;
case 'J': scanSymbol(); return long.class;
case 'S': scanSymbol(); return short.class;
case 'Z': scanSymbol(); return boolean.class;
default:
// Not an elementary type, but a FieldTypeSignature.
return parseFieldTypeSignature();
}
}
void parseMethodTypeSignature() {
// MethodTypeSignature ::= [FormalTypeParameters]
// "(" {TypeSignature} ")" ReturnType {ThrowsSignature}.
parseOptFormalTypeParameters();
parameterTypes = new ListOfTypes(16);
expect('(');
while (symbol != ')' && (symbol > 0)) {
parameterTypes.add(parseTypeSignature());
}
expect(')');
returnType = parseReturnType();
exceptionTypes = new ListOfTypes(8);
while (symbol == '^') {
scanSymbol();
// ThrowsSignature ::= ("^" ClassTypeSignature) |
// ("^" TypeVariableSignature).
if (symbol == 'T') {
exceptionTypes.add(parseTypeVariableSignature());
} else {
exceptionTypes.add(parseClassTypeSignature());
}
}
}
Type parseReturnType() {
// ReturnType ::= TypeSignature | "V".
if (symbol != 'V') { return parseTypeSignature(); }
else { scanSymbol(); return void.class; }
}
//
// Scanner:
//
void scanSymbol() {
if (!eof) {
if (pos < buffer.length) {
symbol = buffer[pos];
pos++;
} else {
symbol = 0;
eof = true;
}
} else {
throw new GenericSignatureFormatError();
}
}
void expect(char c) {
if (symbol == c) {
scanSymbol();
} else {
throw new GenericSignatureFormatError();
}
}
boolean isStopSymbol(char ch) {
switch (ch) {
case ':':
case '/':
case ';':
case '<':
case '.':
return true;
}
return false;
}
// PRE: symbol is the first char of the identifier.
// POST: symbol = the next symbol AFTER the identifier.
void scanIdentifier() {
if (!eof) {
StringBuilder identBuf = new StringBuilder(32);
if (!isStopSymbol(symbol)) {
identBuf.append(symbol);
do {
char ch = buffer[pos];
if ((ch >= 'a') && (ch <= 'z') || (ch >= 'A') && (ch <= 'Z')
|| !isStopSymbol(ch)) {
identBuf.append(buffer[pos]);
pos++;
} else {
identifier = identBuf.toString();
scanSymbol();
return;
}
} while (pos != buffer.length);
identifier = identBuf.toString();
symbol = 0;
eof = true;
} else {
// Ident starts with incorrect char.
symbol = 0;
eof = true;
throw new GenericSignatureFormatError();
}
} else {
throw new GenericSignatureFormatError();
}
}
}
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