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Dynamic scripting for the JVM
/*
* Copyright (C) 2007 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.snapscript.dx.dex.file;
import java.io.PrintWriter;
import java.util.HashSet;
import org.snapscript.dx.dex.code.CatchTable;
import org.snapscript.dx.dex.code.CstInsn;
import org.snapscript.dx.dex.code.DalvCode;
import org.snapscript.dx.dex.code.DalvInsn;
import org.snapscript.dx.dex.code.DalvInsnList;
import org.snapscript.dx.dex.code.LocalList;
import org.snapscript.dx.dex.code.PositionList;
import org.snapscript.dx.rop.cst.Constant;
import org.snapscript.dx.rop.cst.CstMemberRef;
import org.snapscript.dx.rop.cst.CstMethodRef;
import org.snapscript.dx.rop.cst.CstType;
import org.snapscript.dx.rop.type.StdTypeList;
import org.snapscript.dx.rop.type.Type;
import org.snapscript.dx.rop.type.TypeList;
import org.snapscript.dx.util.AnnotatedOutput;
import org.snapscript.dx.util.ExceptionWithContext;
import org.snapscript.dx.util.Hex;
/**
* Representation of all the parts needed for concrete methods in a
* {@code dex} file.
*/
public final class CodeItem extends OffsettedItem {
/** file alignment of this class, in bytes */
private static final int ALIGNMENT = 4;
/** write size of the header of this class, in bytes */
private static final int HEADER_SIZE = 16;
/** {@code non-null;} method that this code implements */
private final CstMethodRef ref;
/** {@code non-null;} the bytecode instructions and associated data */
private final DalvCode code;
/** {@code null-ok;} the catches, if needed; set in {@link #addContents} */
private CatchStructs catches;
/** whether this instance is for a {@code static} method */
private final boolean isStatic;
/**
* {@code non-null;} list of possibly-thrown exceptions; just used in
* generating debugging output (listings)
*/
private final TypeList throwsList;
/**
* {@code null-ok;} the debug info or {@code null} if there is none;
* set in {@link #addContents}
*/
private DebugInfoItem debugInfo;
/**
* Constructs an instance.
*
* @param ref {@code non-null;} method that this code implements
* @param code {@code non-null;} the underlying code
* @param isStatic whether this instance is for a {@code static}
* method
* @param throwsList {@code non-null;} list of possibly-thrown exceptions,
* just used in generating debugging output (listings)
*/
public CodeItem(CstMethodRef ref, DalvCode code, boolean isStatic,
TypeList throwsList) {
super(ALIGNMENT, -1);
if (ref == null) {
throw new NullPointerException("ref == null");
}
if (code == null) {
throw new NullPointerException("code == null");
}
if (throwsList == null) {
throw new NullPointerException("throwsList == null");
}
this.ref = ref;
this.code = code;
this.isStatic = isStatic;
this.throwsList = throwsList;
this.catches = null;
this.debugInfo = null;
}
/** {@inheritDoc} */
@Override
public ItemType itemType() {
return ItemType.TYPE_CODE_ITEM;
}
/** {@inheritDoc} */
public void addContents(DexFile file) {
MixedItemSection byteData = file.getByteData();
TypeIdsSection typeIds = file.getTypeIds();
if (code.hasPositions() || code.hasLocals()) {
debugInfo = new DebugInfoItem(code, isStatic, ref);
byteData.add(debugInfo);
}
if (code.hasAnyCatches()) {
for (Type type : code.getCatchTypes()) {
typeIds.intern(type);
}
catches = new CatchStructs(code);
}
for (Constant c : code.getInsnConstants()) {
file.internIfAppropriate(c);
}
}
/** {@inheritDoc} */
@Override
public String toString() {
return "CodeItem{" + toHuman() + "}";
}
/** {@inheritDoc} */
@Override
public String toHuman() {
return ref.toHuman();
}
/**
* Gets the reference to the method this instance implements.
*
* @return {@code non-null;} the method reference
*/
public CstMethodRef getRef() {
return ref;
}
/**
* Does a human-friendly dump of this instance.
*
* @param out {@code non-null;} where to dump
* @param prefix {@code non-null;} per-line prefix to use
* @param verbose whether to be verbose with the output
*/
public void debugPrint(PrintWriter out, String prefix, boolean verbose) {
out.println(ref.toHuman() + ":");
DalvInsnList insns = code.getInsns();
out.println("regs: " + Hex.u2(getRegistersSize()) +
"; ins: " + Hex.u2(getInsSize()) + "; outs: " +
Hex.u2(getOutsSize()));
insns.debugPrint(out, prefix, verbose);
String prefix2 = prefix + " ";
if (catches != null) {
out.print(prefix);
out.println("catches");
catches.debugPrint(out, prefix2);
}
if (debugInfo != null) {
out.print(prefix);
out.println("debug info");
debugInfo.debugPrint(out, prefix2);
}
}
/** {@inheritDoc} */
@Override
protected void place0(Section addedTo, int offset) {
final DexFile file = addedTo.getFile();
int catchesSize;
/*
* In order to get the catches and insns, all the code's
* constants need to be assigned indices.
*/
code.assignIndices(new DalvCode.AssignIndicesCallback() {
public int getIndex(Constant cst) {
IndexedItem item = file.findItemOrNull(cst);
if (item == null) {
return -1;
}
return item.getIndex();
}
});
if (catches != null) {
catches.encode(file);
catchesSize = catches.writeSize();
} else {
catchesSize = 0;
}
/*
* The write size includes the header, two bytes per code
* unit, post-code padding if necessary, and however much
* space the catches need.
*/
int insnsSize = code.getInsns().codeSize();
if ((insnsSize & 1) != 0) {
insnsSize++;
}
setWriteSize(HEADER_SIZE + (insnsSize * 2) + catchesSize);
}
/** {@inheritDoc} */
@Override
protected void writeTo0(DexFile file, AnnotatedOutput out) {
boolean annotates = out.annotates();
int regSz = getRegistersSize();
int outsSz = getOutsSize();
int insSz = getInsSize();
int insnsSz = code.getInsns().codeSize();
boolean needPadding = (insnsSz & 1) != 0;
int triesSz = (catches == null) ? 0 : catches.triesSize();
int debugOff = (debugInfo == null) ? 0 : debugInfo.getAbsoluteOffset();
if (annotates) {
out.annotate(0, offsetString() + ' ' + ref.toHuman());
out.annotate(2, " registers_size: " + Hex.u2(regSz));
out.annotate(2, " ins_size: " + Hex.u2(insSz));
out.annotate(2, " outs_size: " + Hex.u2(outsSz));
out.annotate(2, " tries_size: " + Hex.u2(triesSz));
out.annotate(4, " debug_off: " + Hex.u4(debugOff));
out.annotate(4, " insns_size: " + Hex.u4(insnsSz));
// This isn't represented directly here, but it is useful to see.
int size = throwsList.size();
if (size != 0) {
out.annotate(0, " throws " + StdTypeList.toHuman(throwsList));
}
}
out.writeShort(regSz);
out.writeShort(insSz);
out.writeShort(outsSz);
out.writeShort(triesSz);
out.writeInt(debugOff);
out.writeInt(insnsSz);
writeCodes(file, out);
if (catches != null) {
if (needPadding) {
if (annotates) {
out.annotate(2, " padding: 0");
}
out.writeShort(0);
}
catches.writeTo(file, out);
}
if (annotates) {
/*
* These are pointed at in the code header (above), but it's less
* distracting to expand on them at the bottom of the code.
*/
if (debugInfo != null) {
out.annotate(0, " debug info");
debugInfo.annotateTo(file, out, " ");
}
}
}
/**
* Helper for {@link #writeTo0} which writes out the actual bytecode.
*
* @param file {@code non-null;} file we are part of
* @param out {@code non-null;} where to write to
*/
private void writeCodes(DexFile file, AnnotatedOutput out) {
DalvInsnList insns = code.getInsns();
try {
insns.writeTo(out);
} catch (RuntimeException ex) {
throw ExceptionWithContext.withContext(ex, "...while writing " +
"instructions for " + ref.toHuman());
}
}
/**
* Get the in registers count.
*
* @return the count
*/
private int getInsSize() {
return ref.getParameterWordCount(isStatic);
}
/**
* Get the out registers count.
*
* @return the count
*/
private int getOutsSize() {
return code.getInsns().getOutsSize();
}
/**
* Get the total registers count.
*
* @return the count
*/
private int getRegistersSize() {
return code.getInsns().getRegistersSize();
}
}