/*
* Copyright (c) 2013, 2016, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
import java.io.*;
import com.sun.tools.classfile.*;
/**
* The {@code ClassFileVisitor} reads a class file using the
* {@code com.sun.tools.classfile} library. It iterates over the methods
* in a class, and checks MethodParameters attributes against JLS
* requirements, as well as assumptions about the javac implementations.
* <p>
* It enforces the following rules:
* <ul>
* <li>All non-synthetic methods with arguments must have the
* MethodParameters attribute. </li>
* <li>At most one MethodParameters attribute per method.</li>
* <li>An empty MethodParameters attribute is not allowed (i.e. no
* attribute for methods taking no parameters).</li>
* <li>The number of recorded parameter names much equal the number
* of parameters, including any implicit or synthetic parameters generated
* by the compiler.</li>
* <li>Although the spec allow recording parameters with no name, the javac
* implementation is assumed to record a name for all parameters. That is,
* the Methodparameters attribute must record a non-zero, valid constant
* pool index for each parameter.</li>
* <li>Check presence, expected names (e.g. this$N, $enum$name, ...) and flags
* (e.g. ACC_SYNTHETIC, ACC_MANDATED) for compiler generated parameters.</li>
* <li>Names of explicit parameters must reflect the names in the Java source.
* This is checked by assuming a design pattern where any name is permitted
* for the first explicit parameter. For subsequent parameters the following
* rule is checked: <i>param[n] == ++param[n-1].charAt(0) + param[n-1]</i>
* </ul>
*/
class ClassFileVisitor extends MethodParametersTester.Visitor {
MethodParametersTester tester;
public String cname;
public boolean isEnum;
public boolean isInterface;
public boolean isInner;
public boolean isPublic;
public boolean isStatic;
public boolean isAnon;
public ClassFile classFile;
public ClassFileVisitor(MethodParametersTester tester) {
super(tester);
}
public void error(String msg) {
super.error("classfile: " + msg);
}
public void warn(String msg) {
super.warn("classfile: " + msg);
}
/**
* Read the class and determine some key characteristics, like if it's
* an enum, or inner class, etc.
*/
void visitClass(final String cname, final File cfile, final StringBuilder sb) throws Exception {
this.cname = cname;
classFile = ClassFile.read(cfile);
isEnum = classFile.access_flags.is(AccessFlags.ACC_ENUM);
isInterface = classFile.access_flags.is(AccessFlags.ACC_INTERFACE);
isPublic = classFile.access_flags.is(AccessFlags.ACC_PUBLIC);
isInner = false;
isStatic = false;
isAnon = false;
Attribute attr = classFile.getAttribute("InnerClasses");
if (attr != null) attr.accept(new InnerClassVisitor(), null);
isAnon = isInner & isAnon;
sb.append(isStatic ? "static " : "")
.append(isPublic ? "public " : "")
.append(isEnum ? "enum " : isInterface ? "interface " : "class ")
.append(cname).append(" -- ");
if (isInner) {
sb.append(isAnon ? "anon" : "inner");
}
sb.append("\n");
for (Method method : classFile.methods) {
new MethodVisitor().visitMethod(method, sb);
}
}
/**
* Used to visit InnerClasses_attribute of a class,
* to determne if this class is an local class, and anonymous
* inner class or a none-static member class. These types of
* classes all have an containing class instances field that
* requires an implicit or synthetic constructor argument.
*/
class InnerClassVisitor extends AttributeVisitor<Void, Void> {
public Void visitInnerClasses(InnerClasses_attribute iattr, Void v) {
try{
for (InnerClasses_attribute.Info info : iattr.classes) {
if (info.getInnerClassInfo(classFile.constant_pool) == null) continue;
String in = info.getInnerClassInfo(classFile.constant_pool).getName();
if (in == null || !cname.equals(in)) continue;
isInner = true;
isAnon = null == info.getInnerName(classFile.constant_pool);
isStatic = info.inner_class_access_flags.is(AccessFlags.ACC_STATIC);
break;
}
} catch(Exception e) {
throw new IllegalStateException(e);
}
return null;
}
}
/**
* Check the MethodParameters attribute of a method.
*/
class MethodVisitor extends AttributeVisitor<Void, StringBuilder> {
public String mName;
public Descriptor mDesc;
public int mParams;
public int mAttrs;
public int mNumParams;
public boolean mSynthetic;
public boolean mIsConstructor;
public boolean mIsClinit;
public boolean mIsBridge;
public boolean isFinal;
public String prefix;
void visitMethod(Method method, StringBuilder sb) throws Exception {
mName = method.getName(classFile.constant_pool);
mDesc = method.descriptor;
mParams = mDesc.getParameterCount(classFile.constant_pool);
mAttrs = method.attributes.attrs.length;
mNumParams = -1; // no MethodParameters attribute found
mSynthetic = method.access_flags.is(AccessFlags.ACC_SYNTHETIC);
mIsConstructor = mName.equals("<init>");
mIsClinit = mName.equals("<clinit>");
prefix = cname + "." + mName + "() - ";
mIsBridge = method.access_flags.is(AccessFlags.ACC_BRIDGE);
if (mIsClinit) {
sb = new StringBuilder(); // Discard output
}
sb.append(cname).append(".").append(mName).append("(");
for (Attribute a : method.attributes) {
a.accept(this, sb);
}
if (mNumParams == -1) {
if (mSynthetic) {
// We don't generate MethodParameters attribute for synthetic
// methods, so we are creating a parameter pattern to match
// ReflectionVisitor API output.
for (int i = 0; i < mParams; i++) {
if (i == 0)
sb.append("arg").append(i);
else
sb.append(", arg").append(i);
}
sb.append(")/*synthetic*/");
} else {
sb.append(")");
}
}
sb.append("\n");
// IMPL: methods with arguments must have a MethodParameters
// attribute, except possibly some synthetic methods.
if (mNumParams == -1 && mParams > 0 && ! mSynthetic) {
error(prefix + "missing MethodParameters attribute");
}
}
public Void visitMethodParameters(MethodParameters_attribute mp,
StringBuilder sb) {
// SPEC: At most one MethodParameters attribute allowed
if (mNumParams != -1) {
error(prefix + "Multiple MethodParameters attributes");
return null;
}
mNumParams = mp.method_parameter_table_length;
// SPEC: An empty attribute is not allowed!
if (mNumParams == 0) {
error(prefix + "0 length MethodParameters attribute");
return null;
}
// SPEC: one name per parameter.
if (mNumParams != mParams) {
error(prefix + "found " + mNumParams +
" parameters, expected " + mParams);
return null;
}
// IMPL: Whether MethodParameters attributes will be generated
// for some synthetics is unresolved. For now, assume no.
if (mSynthetic) {
warn(prefix + "synthetic has MethodParameter attribute");
}
String sep = "";
String userParam = null;
for (int x = 0; x < mNumParams; x++) {
isFinal = (mp.method_parameter_table[x].flags & AccessFlags.ACC_FINAL) != 0;
// IMPL: Assume all parameters are named, something.
int cpi = mp.method_parameter_table[x].name_index;
if (cpi == 0) {
error(prefix + "name expected, param[" + x + "]");
return null;
}
// SPEC: a non 0 index, must be valid!
String param = null;
try {
param = classFile.constant_pool.getUTF8Value(cpi);
if (isFinal)
param = "final " + param;
sb.append(sep).append(param);
sep = ", ";
} catch(ConstantPoolException e) {
error(prefix + "invalid index " + cpi + " for param["
+ x + "]");
return null;
}
// Check availability, flags and special names
int check = checkParam(mp, param, x, sb, isFinal);
if (check < 0) {
return null;
}
// TEST: check test assumptions about parameter name.
// Expected names are calculated starting with the
// 2nd explicit (user given) parameter.
// param[n] == ++param[n-1].charAt(0) + param[n-1]
String expect = null;
if (userParam != null) {
char c = userParam.charAt(0);
expect = (++c) + userParam;
}
if(isFinal && expect != null)
expect = "final " + expect;
if (check > 0) {
if(isFinal) {
userParam = param.substring(6);
} else {
userParam = param;
}
}
if (check > 0 && expect != null && !param.equals(expect)) {
error(prefix + "param[" + x + "]='"
+ param + "' expected '" + expect + "'");
return null;
}
}
if (mSynthetic) {
sb.append(")/*synthetic*/");
} else {
sb.append(")");
}
return null;
}
/*
* Check a parameter for conformity to JLS and javac specific
* assumptions.
* Return -1, if an error is detected. Otherwise, return 0, if
* the parameter is compiler generated, or 1 for an (presumably)
* explicitly declared parameter.
*/
int checkParam(MethodParameters_attribute mp, String param, int index,
StringBuilder sb, boolean isFinal) {
boolean synthetic = (mp.method_parameter_table[index].flags
& AccessFlags.ACC_SYNTHETIC) != 0;
boolean mandated = (mp.method_parameter_table[index].flags
& AccessFlags.ACC_MANDATED) != 0;
// Setup expectations for flags and special names
String expect = null;
boolean allowMandated = false;
boolean allowSynthetic = false;
if (mSynthetic || synthetic) {
// not an implementation gurantee, but okay for now
expect = "arg" + index; // default
}
if (mIsConstructor) {
if (isEnum) {
if (index == 0) {
expect = "\\$enum\\$name";
allowSynthetic = true;
} else if(index == 1) {
expect = "\\$enum\\$ordinal";
allowSynthetic = true;
}
} else if (index == 0) {
if (isAnon) {
expect = "this\\$[0-9]+";
allowMandated = true;
if (isFinal) {
expect = "final this\\$[0-9]+";
}
} else if (isInner && !isStatic) {
expect = "this\\$[0-9]+";
allowMandated = true;
if (!isPublic) {
// some but not all non-public inner classes
// have synthetic argument. For now we give
// the test a bit of slack and allow either.
allowSynthetic = true;
}
if (isFinal) {
expect = "final this\\$[0-9]+";
}
}
}
if (synthetic && !mandated && !allowSynthetic) {
//patch treatment for local captures
if (isAnon || (isInner & !isStatic)) {
expect = "val\\$.*";
allowSynthetic = true;
if (isFinal) {
expect = "final val\\$.*";
}
}
}
} else if (isEnum && mNumParams == 1 && index == 0 && mName.equals("valueOf")) {
expect = "name";
allowMandated = true;
} else if (mIsBridge) {
allowSynthetic = true;
/* you can't expect an special name for bridges' parameters.
* The name of the original parameters are now copied.
*/
expect = null;
}
if (mandated) sb.append("/*implicit*/");
if (synthetic) sb.append("/*synthetic*/");
// IMPL: our rules a somewhat fuzzy, sometimes allowing both mandated
// and synthetic. However, a parameters cannot be both.
if (mandated && synthetic) {
error(prefix + "param[" + index + "] == \"" + param
+ "\" ACC_SYNTHETIC and ACC_MANDATED");
return -1;
}
// ... but must be either, if both "allowed".
if (!(mandated || synthetic) && allowMandated && allowSynthetic) {
error(prefix + "param[" + index + "] == \"" + param
+ "\" expected ACC_MANDATED or ACC_SYNTHETIC");
return -1;
}
// ... if only one is "allowed", we meant "required".
if (!mandated && allowMandated && !allowSynthetic) {
error(prefix + "param[" + index + "] == \"" + param
+ "\" expected ACC_MANDATED");
return -1;
}
if (!synthetic && !allowMandated && allowSynthetic) {
error(prefix + "param[" + index + "] == \"" + param
+ "\" expected ACC_SYNTHETIC");
return -1;
}
// ... and not "allowed", means prohibited.
if (mandated && !allowMandated) {
error(prefix + "param[" + index + "] == \"" + param
+ "\" unexpected, is ACC_MANDATED");
return -1;
}
if (synthetic && !allowSynthetic) {
error(prefix + "param[" + index + "] == \"" + param
+ "\" unexpected, is ACC_SYNTHETIC");
return -1;
}
// Test special name expectations
if (expect != null) {
if (param.matches(expect)) {
return 0;
}
error(prefix + "param[" + index + "]='" + param +
"' expected '" + expect + "'");
return -1;
}
// No further checking for synthetic methods.
if (mSynthetic) {
return 0;
}
// Otherwise, do check test parameter naming convention.
return 1;
}
}
}