public StringBuffer printSymbolTree(int linebreakpos, boolean preserveAllSemiColons) throws IOException { offset = 0; braceNesting = 0; scopes.clear(); String symbol; JavaScriptToken token; // begin if (tokens.size() == 0) { StringBuffer result = new StringBuffer(); return result; } // end JavaScriptToken lastToken = getToken(0); ScriptOrFnScope currentScope; JavaScriptIdentifier identifier; int length = tokens.size(); // 文本的长度 StringBuffer result = new StringBuffer(); int linestartpos = 0; enterScope(globalScope); // 将globalScope压入栈scopes中 while (offset < length) { token = consumeToken(); symbol = token.getValue(); currentScope = getCurrentScope(); switch (token.getType()) { case Token.GET: case Token.SET: lastToken = token; // 注意没有break; case Token.NAME: if (offset >= 2 && getToken(-2).getType() == Token.DOT || getToken(0).getType() == Token.OBJECTLIT) { result.append(symbol); } else { identifier = getIdentifier(symbol, currentScope); if (identifier != null) { if (identifier.getMungedValue() != null) { result.append(identifier.getMungedValue()); } else { result.append(symbol); } if (currentScope != globalScope // 全局域中的变量可能被HTML文档使用,不需要发出警告 && identifier.getRefcount() == 0) { warn("标识符" + symbol + "已经声明但未使用 ", true); } } else { result.append(symbol); } } break; case Token.REGEXP: case Token.STRING: result.append(symbol); break; case Token.NUMBER: if (getToken(0).getType() == Token.DOT) { // calling methods on int requires a leading dot so JS // doesn't // treat the method as the decimal component of a float result.append('('); result.append(symbol); result.append(')'); } else { result.append(symbol); } break; case Token.ADD: case Token.SUB: result.append(literals.get(new Integer(token.getType()))); if (offset < length) { token = getToken(0); if (token.getType() == Token.INC || token.getType() == Token.DEC || token.getType() == Token.ADD || token.getType() == Token.DEC) { // Handle the case x +/- ++/-- y // We must keep a white space here. Otherwise, x +++ y // would be // interpreted as x ++ + y by the compiler, which is a // bug (due // to the implicit(隐式的) assignment being done on the // wrong variable) result.append(' '); } else if (token.getType() == Token.POS && getToken(-1).getType() == Token.ADD || token.getType() == Token.NEG && getToken(-1).getType() == Token.SUB) { // Handle the case x + + y and x - - y result.append(' '); } } break; case Token.FUNCTION: if (lastToken.getType() != Token.GET && lastToken.getType() != Token.SET) { result.append("function"); } lastToken = token; token = consumeToken(); if (token.getType() == Token.NAME) { result.append(' '); symbol = token.getValue(); identifier = getIdentifier(symbol, currentScope); assert identifier != null; if (identifier.getMungedValue() != null) { result.append(identifier.getMungedValue()); } else { result.append(symbol); } if (currentScope != globalScope && identifier.getRefcount() == 0) { warn("标识符" + symbol + "已经声明但未使用", true); } token = consumeToken(); } assert token.getType() == Token.LP; result.append('('); currentScope = indexedScopes.get(new Integer(offset)); // 根据左圆括号的下一个索引映射得到函数作用域 enterScope(currentScope); while ((token = consumeToken()).getType() != Token.RP) { assert token.getType() == Token.NAME || token.getType() == Token.COMMA; if (token.getType() == Token.NAME) { symbol = token.getValue(); identifier = getIdentifier(symbol, currentScope); assert identifier != null; if (identifier.getMungedValue() != null) { result.append(identifier.getMungedValue()); } else { result.append(symbol); } } else if (token.getType() == Token.COMMA) { result.append(','); } } result.append(')'); token = consumeToken(); // 得到左花括号 assert token.getType() == Token.LC; result.append("{"); // nomodify braceNesting++; token = getToken(0); if (token.getType() == Token.STRING && getToken(1).getType() == Token.SEMI) { // This is a hint. Skip it! consumeToken(); consumeToken(); } break; case Token.RETURN: case Token.TYPEOF: result.append(literals.get(new Integer(token.getType()))); // No space needed after 'return' and 'typeof' when followed // by '(', '[', '{', a string or a regexp. if (offset < length) { token = getToken(0); if (token.getType() != Token.LP && token.getType() != Token.LB && token.getType() != Token.LC && token.getType() != Token.STRING && token.getType() != Token.REGEXP && token.getType() != Token.SEMI) { result.append(' '); } } break; case Token.CASE: case Token.THROW: result.append(literals.get(new Integer(token.getType()))); // White-space needed after 'case' and 'throw' when not followed // by a string. if (offset < length && getToken(0).getType() != Token.STRING) { result.append(' '); } break; case Token.BREAK: case Token.CONTINUE: result.append(literals.get(new Integer(token.getType()))); if (offset < length && getToken(0).getType() != Token.SEMI) { // If 'break' or 'continue' is not followed by a // semi-colon(分号), it must // be followed by a label, hence(因此) the need for a white // space. result.append(' '); } break; case Token.LC: result.append("{"); // nomodify braceNesting++; break; case Token.RC: result.append('}'); braceNesting--; assert braceNesting >= currentScope.getBraceNesting(); if (braceNesting == currentScope.getBraceNesting()) { leaveCurrentScope(); } break; case Token.SEMI: // No need to output a semi-colon if the next character is a // right-curly... if (preserveAllSemiColons || offset < length && getToken(0).getType() != Token.RC) { result.append(';'); } if (linebreakpos >= 0 && result.length() - linestartpos > linebreakpos) { // Some source control tools don't like it when files // containing lines longer // than, say 8000 characters, are checked in. The linebreak // option is used in // that case to split long lines after a specific column. result.append('\n'); linestartpos = result.length(); } break; case Token.COMMA: // No need to output a comma if the next character is a // right-curly or a right-square bracket if (offset < length && getToken(0).getType() != Token.RC && getToken(0).getType() != Token.RB) { result.append(','); } break; case Token.CONDCOMMENT: case Token.KEEPCOMMENT: if (result.length() > 0 && result.charAt(result.length() - 1) != '\n') { result.append("\n"); } result.append("/*"); if (token.getType() == Token.KEEPCOMMENT) { result.append("!"); } result.append(symbol); result.append("*/\n"); break; // begin--这个分支用于实现压扁控制流 // 此分支将if(expression){...}else if(expression){...}else{...}转化为 // switch(expression){case true:原if块;break;case false:原else块;break;} case Token.IF: if (!EditOptionPanel.checkBoxFlatten.isSelected()) { result.append(symbol); break; } FlattenIF flattenIF = new FlattenIF(offset, length, tokens, currentScope); String switchBlock = flattenIF.flattenIF(); result.append(switchBlock); offset = flattenIF.offset; break; case Token.WHILE: if (!EditOptionPanel.checkBoxOpacity.isSelected()) { result.append(symbol); break; } result.append(symbol); OpacityPredicate opacityPredicateWhile = new OpacityPredicate(offset, tokens, currentScope); String whileBlock = opacityPredicateWhile.opacityPredicateWhile(); result.append(whileBlock); offset = opacityPredicateWhile.offset; break; case Token.DO: if (!EditOptionPanel.checkBoxOpacity.isSelected()) { result.append(symbol); break; } result.append(symbol); OpacityPredicate opacityPredicateDoWhile = new OpacityPredicate(offset, tokens, currentScope); String doWhileBlock = opacityPredicateDoWhile.opacityPredicateDoWhile(); result.append(doWhileBlock); offset = opacityPredicateDoWhile.offset; break; // end default: String literal = literals.get(new Integer(token.getType())); if (literal != null) { result.append(literal); } else { warn("此标志符不能被打印出来:" + symbol, true); } break; } } // Append a semi-colon at the end, even if unnecessary semi-colons are // supposed to be removed. This is especially useful when concatenating // several minified files (the absence of an ending semi-colon at the // end of one file may very likely cause a syntax error) /*if (!preserveAllSemiColons && result.length() > 0 && getToken(-1).getType() != Token.CONDCOMMENT && getToken(-1).getType() != Token.KEEPCOMMENT) { if (result.charAt(result.length() - 1) == '\n') { result.setCharAt(result.length() - 1, ';'); } else { result.append(';'); } }*/ // 暂时用不上,注释掉 return result; }