diff options
Diffstat (limited to 'trunk/infrastructure/rhino1_7R1/src/org/mozilla/javascript/Decompiler.java')
| -rw-r--r-- | trunk/infrastructure/rhino1_7R1/src/org/mozilla/javascript/Decompiler.java | 918 |
1 files changed, 918 insertions, 0 deletions
diff --git a/trunk/infrastructure/rhino1_7R1/src/org/mozilla/javascript/Decompiler.java b/trunk/infrastructure/rhino1_7R1/src/org/mozilla/javascript/Decompiler.java new file mode 100644 index 0000000..8547d37 --- /dev/null +++ b/trunk/infrastructure/rhino1_7R1/src/org/mozilla/javascript/Decompiler.java @@ -0,0 +1,918 @@ +/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- + * + * ***** BEGIN LICENSE BLOCK ***** + * Version: MPL 1.1/GPL 2.0 + * + * The contents of this file are subject to the Mozilla Public License Version + * 1.1 (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.mozilla.org/MPL/ + * + * Software distributed under the License is distributed on an "AS IS" basis, + * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License + * for the specific language governing rights and limitations under the + * License. + * + * The Original Code is Rhino code, released + * May 6, 1999. + * + * The Initial Developer of the Original Code is + * Netscape Communications Corporation. + * Portions created by the Initial Developer are Copyright (C) 1997-1999 + * the Initial Developer. All Rights Reserved. + * + * Contributor(s): + * Mike Ang + * Igor Bukanov + * Bob Jervis + * Mike McCabe + * + * Alternatively, the contents of this file may be used under the terms of + * the GNU General Public License Version 2 or later (the "GPL"), in which + * case the provisions of the GPL are applicable instead of those above. If + * you wish to allow use of your version of this file only under the terms of + * the GPL and not to allow others to use your version of this file under the + * MPL, indicate your decision by deleting the provisions above and replacing + * them with the notice and other provisions required by the GPL. If you do + * not delete the provisions above, a recipient may use your version of this + * file under either the MPL or the GPL. + * + * ***** END LICENSE BLOCK ***** */ + +package org.mozilla.javascript; + +/** + * The following class save decompilation information about the source. + * Source information is returned from the parser as a String + * associated with function nodes and with the toplevel script. When + * saved in the constant pool of a class, this string will be UTF-8 + * encoded, and token values will occupy a single byte. + + * Source is saved (mostly) as token numbers. The tokens saved pretty + * much correspond to the token stream of a 'canonical' representation + * of the input program, as directed by the parser. (There were a few + * cases where tokens could have been left out where decompiler could + * easily reconstruct them, but I left them in for clarity). (I also + * looked adding source collection to TokenStream instead, where I + * could have limited the changes to a few lines in getToken... but + * this wouldn't have saved any space in the resulting source + * representation, and would have meant that I'd have to duplicate + * parser logic in the decompiler to disambiguate situations where + * newlines are important.) The function decompile expands the + * tokens back into their string representations, using simple + * lookahead to correct spacing and indentation. + * + * Assignments are saved as two-token pairs (Token.ASSIGN, op). Number tokens + * are stored inline, as a NUMBER token, a character representing the type, and + * either 1 or 4 characters representing the bit-encoding of the number. String + * types NAME, STRING and OBJECT are currently stored as a token type, + * followed by a character giving the length of the string (assumed to + * be less than 2^16), followed by the characters of the string + * inlined into the source string. Changing this to some reference to + * to the string in the compiled class' constant pool would probably + * save a lot of space... but would require some method of deriving + * the final constant pool entry from information available at parse + * time. + */ +public class Decompiler +{ + /** + * Flag to indicate that the decompilation should omit the + * function header and trailing brace. + */ + public static final int ONLY_BODY_FLAG = 1 << 0; + + /** + * Flag to indicate that the decompilation generates toSource result. + */ + public static final int TO_SOURCE_FLAG = 1 << 1; + + /** + * Decompilation property to specify initial ident value. + */ + public static final int INITIAL_INDENT_PROP = 1; + + /** + * Decompilation property to specify default identation offset. + */ + public static final int INDENT_GAP_PROP = 2; + + /** + * Decompilation property to specify identation offset for case labels. + */ + public static final int CASE_GAP_PROP = 3; + + // Marker to denote the last RC of function so it can be distinguished from + // the last RC of object literals in case of function expressions + private static final int FUNCTION_END = Token.LAST_TOKEN + 1; + + String getEncodedSource() + { + return sourceToString(0); + } + + int getCurrentOffset() + { + return sourceTop; + } + + int markFunctionStart(int functionType) + { + int savedOffset = getCurrentOffset(); + addToken(Token.FUNCTION); + append((char)functionType); + return savedOffset; + } + + int markFunctionEnd(int functionStart) + { + int offset = getCurrentOffset(); + append((char)FUNCTION_END); + return offset; + } + + void addToken(int token) + { + if (!(0 <= token && token <= Token.LAST_TOKEN)) + throw new IllegalArgumentException(); + + append((char)token); + } + + void addEOL(int token) + { + if (!(0 <= token && token <= Token.LAST_TOKEN)) + throw new IllegalArgumentException(); + + append((char)token); + append((char)Token.EOL); + } + + void addName(String str) + { + addToken(Token.NAME); + appendString(str); + } + + void addString(String str) + { + addToken(Token.STRING); + appendString(str); + } + + void addRegexp(String regexp, String flags) + { + addToken(Token.REGEXP); + appendString('/' + regexp + '/' + flags); + } + + void addNumber(double n) + { + addToken(Token.NUMBER); + + /* encode the number in the source stream. + * Save as NUMBER type (char | char char char char) + * where type is + * 'D' - double, 'S' - short, 'J' - long. + + * We need to retain float vs. integer type info to keep the + * behavior of liveconnect type-guessing the same after + * decompilation. (Liveconnect tries to present 1.0 to Java + * as a float/double) + * OPT: This is no longer true. We could compress the format. + + * This may not be the most space-efficient encoding; + * the chars created below may take up to 3 bytes in + * constant pool UTF-8 encoding, so a Double could take + * up to 12 bytes. + */ + + long lbits = (long)n; + if (lbits != n) { + // if it's floating point, save as a Double bit pattern. + // (12/15/97 our scanner only returns Double for f.p.) + lbits = Double.doubleToLongBits(n); + append('D'); + append((char)(lbits >> 48)); + append((char)(lbits >> 32)); + append((char)(lbits >> 16)); + append((char)lbits); + } + else { + // we can ignore negative values, bc they're already prefixed + // by NEG + if (lbits < 0) Kit.codeBug(); + + // will it fit in a char? + // this gives a short encoding for integer values up to 2^16. + if (lbits <= Character.MAX_VALUE) { + append('S'); + append((char)lbits); + } + else { // Integral, but won't fit in a char. Store as a long. + append('J'); + append((char)(lbits >> 48)); + append((char)(lbits >> 32)); + append((char)(lbits >> 16)); + append((char)lbits); + } + } + } + + private void appendString(String str) + { + int L = str.length(); + int lengthEncodingSize = 1; + if (L >= 0x8000) { + lengthEncodingSize = 2; + } + int nextTop = sourceTop + lengthEncodingSize + L; + if (nextTop > sourceBuffer.length) { + increaseSourceCapacity(nextTop); + } + if (L >= 0x8000) { + // Use 2 chars to encode strings exceeding 32K, were the highest + // bit in the first char indicates presence of the next byte + sourceBuffer[sourceTop] = (char)(0x8000 | (L >>> 16)); + ++sourceTop; + } + sourceBuffer[sourceTop] = (char)L; + ++sourceTop; + str.getChars(0, L, sourceBuffer, sourceTop); + sourceTop = nextTop; + } + + private void append(char c) + { + if (sourceTop == sourceBuffer.length) { + increaseSourceCapacity(sourceTop + 1); + } + sourceBuffer[sourceTop] = c; + ++sourceTop; + } + + private void increaseSourceCapacity(int minimalCapacity) + { + // Call this only when capacity increase is must + if (minimalCapacity <= sourceBuffer.length) Kit.codeBug(); + int newCapacity = sourceBuffer.length * 2; + if (newCapacity < minimalCapacity) { + newCapacity = minimalCapacity; + } + char[] tmp = new char[newCapacity]; + System.arraycopy(sourceBuffer, 0, tmp, 0, sourceTop); + sourceBuffer = tmp; + } + + private String sourceToString(int offset) + { + if (offset < 0 || sourceTop < offset) Kit.codeBug(); + return new String(sourceBuffer, offset, sourceTop - offset); + } + + /** + * Decompile the source information associated with this js + * function/script back into a string. For the most part, this + * just means translating tokens back to their string + * representations; there's a little bit of lookahead logic to + * decide the proper spacing/indentation. Most of the work in + * mapping the original source to the prettyprinted decompiled + * version is done by the parser. + * + * @param source encoded source tree presentation + * + * @param flags flags to select output format + * + * @param properties indentation properties + * + */ + public static String decompile(String source, int flags, + UintMap properties) + { + int length = source.length(); + if (length == 0) { return ""; } + + int indent = properties.getInt(INITIAL_INDENT_PROP, 0); + if (indent < 0) throw new IllegalArgumentException(); + int indentGap = properties.getInt(INDENT_GAP_PROP, 4); + if (indentGap < 0) throw new IllegalArgumentException(); + int caseGap = properties.getInt(CASE_GAP_PROP, 2); + if (caseGap < 0) throw new IllegalArgumentException(); + + StringBuffer result = new StringBuffer(); + boolean justFunctionBody = (0 != (flags & Decompiler.ONLY_BODY_FLAG)); + boolean toSource = (0 != (flags & Decompiler.TO_SOURCE_FLAG)); + + // Spew tokens in source, for debugging. + // as TYPE number char + if (printSource) { + System.err.println("length:" + length); + for (int i = 0; i < length; ++i) { + // Note that tokenToName will fail unless Context.printTrees + // is true. + String tokenname = null; + if (Token.printNames) { + tokenname = Token.name(source.charAt(i)); + } + if (tokenname == null) { + tokenname = "---"; + } + String pad = tokenname.length() > 7 + ? "\t" + : "\t\t"; + System.err.println + (tokenname + + pad + (int)source.charAt(i) + + "\t'" + ScriptRuntime.escapeString + (source.substring(i, i+1)) + + "'"); + } + System.err.println(); + } + + int braceNesting = 0; + boolean afterFirstEOL = false; + int i = 0; + int topFunctionType; + if (source.charAt(i) == Token.SCRIPT) { + ++i; + topFunctionType = -1; + } else { + topFunctionType = source.charAt(i + 1); + } + + if (!toSource) { + // add an initial newline to exactly match js. + result.append('\n'); + for (int j = 0; j < indent; j++) + result.append(' '); + } else { + if (topFunctionType == FunctionNode.FUNCTION_EXPRESSION) { + result.append('('); + } + } + + while (i < length) { + switch(source.charAt(i)) { + case Token.GET: + case Token.SET: + result.append(source.charAt(i) == Token.GET ? "get " : "set "); + ++i; + i = printSourceString(source, i + 1, false, result); + // Now increment one more to get past the FUNCTION token + ++i; + break; + + case Token.NAME: + case Token.REGEXP: // re-wrapped in '/'s in parser... + i = printSourceString(source, i + 1, false, result); + continue; + + case Token.STRING: + i = printSourceString(source, i + 1, true, result); + continue; + + case Token.NUMBER: + i = printSourceNumber(source, i + 1, result); + continue; + + case Token.TRUE: + result.append("true"); + break; + + case Token.FALSE: + result.append("false"); + break; + + case Token.NULL: + result.append("null"); + break; + + case Token.THIS: + result.append("this"); + break; + + case Token.FUNCTION: + ++i; // skip function type + result.append("function "); + break; + + case FUNCTION_END: + // Do nothing + break; + + case Token.COMMA: + result.append(", "); + break; + + case Token.LC: + ++braceNesting; + if (Token.EOL == getNext(source, length, i)) + indent += indentGap; + result.append('{'); + break; + + case Token.RC: { + --braceNesting; + /* don't print the closing RC if it closes the + * toplevel function and we're called from + * decompileFunctionBody. + */ + if (justFunctionBody && braceNesting == 0) + break; + + result.append('}'); + switch (getNext(source, length, i)) { + case Token.EOL: + case FUNCTION_END: + indent -= indentGap; + break; + case Token.WHILE: + case Token.ELSE: + indent -= indentGap; + result.append(' '); + break; + } + break; + } + case Token.LP: + result.append('('); + break; + + case Token.RP: + result.append(')'); + if (Token.LC == getNext(source, length, i)) + result.append(' '); + break; + + case Token.LB: + result.append('['); + break; + + case Token.RB: + result.append(']'); + break; + + case Token.EOL: { + if (toSource) break; + boolean newLine = true; + if (!afterFirstEOL) { + afterFirstEOL = true; + if (justFunctionBody) { + /* throw away just added 'function name(...) {' + * and restore the original indent + */ + result.setLength(0); + indent -= indentGap; + newLine = false; + } + } + if (newLine) { + result.append('\n'); + } + + /* add indent if any tokens remain, + * less setback if next token is + * a label, case or default. + */ + if (i + 1 < length) { + int less = 0; + int nextToken = source.charAt(i + 1); + if (nextToken == Token.CASE + || nextToken == Token.DEFAULT) + { + less = indentGap - caseGap; + } else if (nextToken == Token.RC) { + less = indentGap; + } + + /* elaborate check against label... skip past a + * following inlined NAME and look for a COLON. + */ + else if (nextToken == Token.NAME) { + int afterName = getSourceStringEnd(source, i + 2); + if (source.charAt(afterName) == Token.COLON) + less = indentGap; + } + + for (; less < indent; less++) + result.append(' '); + } + break; + } + case Token.DOT: + result.append('.'); + break; + + case Token.NEW: + result.append("new "); + break; + + case Token.DELPROP: + result.append("delete "); + break; + + case Token.IF: + result.append("if "); + break; + + case Token.ELSE: + result.append("else "); + break; + + case Token.FOR: + result.append("for "); + break; + + case Token.IN: + result.append(" in "); + break; + + case Token.WITH: + result.append("with "); + break; + + case Token.WHILE: + result.append("while "); + break; + + case Token.DO: + result.append("do "); + break; + + case Token.TRY: + result.append("try "); + break; + + case Token.CATCH: + result.append("catch "); + break; + + case Token.FINALLY: + result.append("finally "); + break; + + case Token.THROW: + result.append("throw "); + break; + + case Token.SWITCH: + result.append("switch "); + break; + + case Token.BREAK: + result.append("break"); + if (Token.NAME == getNext(source, length, i)) + result.append(' '); + break; + + case Token.CONTINUE: + result.append("continue"); + if (Token.NAME == getNext(source, length, i)) + result.append(' '); + break; + + case Token.CASE: + result.append("case "); + break; + + case Token.DEFAULT: + result.append("default"); + break; + + case Token.RETURN: + result.append("return"); + if (Token.SEMI != getNext(source, length, i)) + result.append(' '); + break; + + case Token.VAR: + result.append("var "); + break; + + case Token.LET: + result.append("let "); + break; + + case Token.SEMI: + result.append(';'); + if (Token.EOL != getNext(source, length, i)) { + // separators in FOR + result.append(' '); + } + break; + + case Token.ASSIGN: + result.append(" = "); + break; + + case Token.ASSIGN_ADD: + result.append(" += "); + break; + + case Token.ASSIGN_SUB: + result.append(" -= "); + break; + + case Token.ASSIGN_MUL: + result.append(" *= "); + break; + + case Token.ASSIGN_DIV: + result.append(" /= "); + break; + + case Token.ASSIGN_MOD: + result.append(" %= "); + break; + + case Token.ASSIGN_BITOR: + result.append(" |= "); + break; + + case Token.ASSIGN_BITXOR: + result.append(" ^= "); + break; + + case Token.ASSIGN_BITAND: + result.append(" &= "); + break; + + case Token.ASSIGN_LSH: + result.append(" <<= "); + break; + + case Token.ASSIGN_RSH: + result.append(" >>= "); + break; + + case Token.ASSIGN_URSH: + result.append(" >>>= "); + break; + + case Token.HOOK: + result.append(" ? "); + break; + + case Token.OBJECTLIT: + // pun OBJECTLIT to mean colon in objlit property + // initialization. + // This needs to be distinct from COLON in the general case + // to distinguish from the colon in a ternary... which needs + // different spacing. + result.append(':'); + break; + + case Token.COLON: + if (Token.EOL == getNext(source, length, i)) + // it's the end of a label + result.append(':'); + else + // it's the middle part of a ternary + result.append(" : "); + break; + + case Token.OR: + result.append(" || "); + break; + + case Token.AND: + result.append(" && "); + break; + + case Token.BITOR: + result.append(" | "); + break; + + case Token.BITXOR: + result.append(" ^ "); + break; + + case Token.BITAND: + result.append(" & "); + break; + + case Token.SHEQ: + result.append(" === "); + break; + + case Token.SHNE: + result.append(" !== "); + break; + + case Token.EQ: + result.append(" == "); + break; + + case Token.NE: + result.append(" != "); + break; + + case Token.LE: + result.append(" <= "); + break; + + case Token.LT: + result.append(" < "); + break; + + case Token.GE: + result.append(" >= "); + break; + + case Token.GT: + result.append(" > "); + break; + + case Token.INSTANCEOF: + result.append(" instanceof "); + break; + + case Token.LSH: + result.append(" << "); + break; + + case Token.RSH: + result.append(" >> "); + break; + + case Token.URSH: + result.append(" >>> "); + break; + + case Token.TYPEOF: + result.append("typeof "); + break; + + case Token.VOID: + result.append("void "); + break; + + case Token.CONST: + result.append("const "); + break; + + case Token.YIELD: + result.append("yield "); + break; + + case Token.NOT: + result.append('!'); + break; + + case Token.BITNOT: + result.append('~'); + break; + + case Token.POS: + result.append('+'); + break; + + case Token.NEG: + result.append('-'); + break; + + case Token.INC: + result.append("++"); + break; + + case Token.DEC: + result.append("--"); + break; + + case Token.ADD: + result.append(" + "); + break; + + case Token.SUB: + result.append(" - "); + break; + + case Token.MUL: + result.append(" * "); + break; + + case Token.DIV: + result.append(" / "); + break; + + case Token.MOD: + result.append(" % "); + break; + + case Token.COLONCOLON: + result.append("::"); + break; + + case Token.DOTDOT: + result.append(".."); + break; + + case Token.DOTQUERY: + result.append(".("); + break; + + case Token.XMLATTR: + result.append('@'); + break; + + default: + // If we don't know how to decompile it, raise an exception. + throw new RuntimeException("Token: " + + Token.name(source.charAt(i))); + } + ++i; + } + + if (!toSource) { + // add that trailing newline if it's an outermost function. + if (!justFunctionBody) + result.append('\n'); + } else { + if (topFunctionType == FunctionNode.FUNCTION_EXPRESSION) { + result.append(')'); + } + } + + return result.toString(); + } + + private static int getNext(String source, int length, int i) + { + return (i + 1 < length) ? source.charAt(i + 1) : Token.EOF; + } + + private static int getSourceStringEnd(String source, int offset) + { + return printSourceString(source, offset, false, null); + } + + private static int printSourceString(String source, int offset, + boolean asQuotedString, + StringBuffer sb) + { + int length = source.charAt(offset); + ++offset; + if ((0x8000 & length) != 0) { + length = ((0x7FFF & length) << 16) | source.charAt(offset); + ++offset; + } + if (sb != null) { + String str = source.substring(offset, offset + length); + if (!asQuotedString) { + sb.append(str); + } else { + sb.append('"'); + sb.append(ScriptRuntime.escapeString(str)); + sb.append('"'); + } + } + return offset + length; + } + + private static int printSourceNumber(String source, int offset, + StringBuffer sb) + { + double number = 0.0; + char type = source.charAt(offset); + ++offset; + if (type == 'S') { + if (sb != null) { + int ival = source.charAt(offset); + number = ival; + } + ++offset; + } else if (type == 'J' || type == 'D') { + if (sb != null) { + long lbits; + lbits = (long)source.charAt(offset) << 48; + lbits |= (long)source.charAt(offset + 1) << 32; + lbits |= (long)source.charAt(offset + 2) << 16; + lbits |= source.charAt(offset + 3); + if (type == 'J') { + number = lbits; + } else { + number = Double.longBitsToDouble(lbits); + } + } + offset += 4; + } else { + // Bad source + throw new RuntimeException(); + } + if (sb != null) { + sb.append(ScriptRuntime.numberToString(number, 10)); + } + return offset; + } + + private char[] sourceBuffer = new char[128]; + +// Per script/function source buffer top: parent source does not include a +// nested functions source and uses function index as a reference instead. + private int sourceTop; + +// whether to do a debug print of the source information, when decompiling. + private static final boolean printSource = false; + +} |