// 建立语法树
public void buildSymbolTree() {
offset = 0;
braceNesting = 0; // 花括号嵌套
scopes.clear(); // 清空栈
indexedScopes.clear(); // 清空哈希表
indexedScopes.put(new Integer(0), globalScope); // gloabalScope为ScriptOrFnScope对象，构造函数参数为-1,null
mode = BUILDING_SYMBOL_TREE; // （BUILDING_SYMBOL_TREE值为1）
parseScope(globalScope);
globalScope.warning();
}
private void parseFunctionDeclaration() {
String symbol;
JavaScriptToken token;
ScriptOrFnScope currentScope, fnScope;
JavaScriptIdentifier identifier;
currentScope = getCurrentScope(); // 得到此函数声明所在的域
token = consumeToken();
// 如果是函数名（说明这种函数的声明方式是：function funName(){}）
// 否则是：var varName = function(){}
if (token.getType() == Token.NAME) {
if (mode == BUILDING_SYMBOL_TREE) {
// Get the name of the function and declare it in the current
// scope.
symbol = token.getValue(); // 得到的是函数名
if (currentScope.getIdentifier(symbol) != null) {
warn("函数" + symbol + "已经在相同的作用域中声明。", true);
}
currentScope.declareIdentifier(symbol, false); // 在本作用域中声明标识符
}
token = consumeToken(); // 得到左圆括号
}
assert token.getType() == Token.LP;
if (mode == BUILDING_SYMBOL_TREE) {
fnScope = new ScriptOrFnScope(braceNesting, currentScope); // 新建一个作用域，并把当前域传递过去最为父作用域
indexedScopes.put(new Integer(offset), fnScope); // 圆括号的下一个索引映射到函数作用域
} else {
fnScope = indexedScopes.get(new Integer(offset));
}
// Parse function arguments.解释函数参数
int argpos = 0;
while ((token = consumeToken()).getType() != Token.RP) {
assert token.getType() == Token.NAME || token.getType() == Token.COMMA;
if (token.getType() == Token.NAME && mode == BUILDING_SYMBOL_TREE) {
symbol = token.getValue();
identifier = fnScope.declareIdentifier(symbol, false);
if (symbol.equals("$super") && argpos == 0) {
// Exception for Prototype 1.6...
identifier.preventMunging();
}
argpos++;
}
}
token = consumeToken(); // 得到函数的左花括号
assert token.getType() == Token.LC;
braceNesting++;
token = getToken(0);
if (token.getType() == Token.STRING && getToken(1).getType() == Token.SEMI) {
// This is a hint. Hints are empty statements that look like
// "localvar1:nomunge, localvar2:nomunge"; They allow developers
// to prevent specific symbols from getting obfuscated (some heretic
// implementations, such as Prototype 1.6, require specific variable
// names, such as $super for example, in order to work
// appropriately.
// Note: right now, only "nomunge" is supported in the right hand
// side
// of a hint. However, in the future, the right hand side(右边) may
// contain
// other values.
consumeToken();
String hints = token.getValue();
// Remove the leading and trailing quotes...
hints = hints.substring(1, hints.length() - 1).trim();
StringTokenizer st1 = new StringTokenizer(hints, ","); // Tokenizer分词器,以','为分词界限
while (st1.hasMoreTokens()) {
String hint = st1.nextToken();
int idx = hint.indexOf(':');
if (idx <= 0 || idx >= hint.length() - 1) {
if (mode == BUILDING_SYMBOL_TREE) {
// No need to report the error twice, hence the test...
warn("提示语句有语法错误：" + hint, true);
}
break;
}
String variableName = hint.substring(0, idx).trim();
String variableType = hint.substring(idx + 1).trim();
if (mode == BUILDING_SYMBOL_TREE) {
fnScope.addHint(variableName, variableType);
} else if (mode == CHECKING_SYMBOL_TREE) {
identifier = fnScope.getIdentifier(variableName);
if (identifier != null) {
if (variableType.equals("nomunge")) {
identifier.preventMunging();
} else {
warn("不支持的提示指令： " + hint, true);
}
} else {
warn("提示指令指向未知的标识符: " + hint, true);
}
}
}
}
parseScope(fnScope); // 解释函数域
}