| /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- |
| * vim: set ts=8 sts=4 et sw=4 tw=99: |
| * This Source Code Form is subject to the terms of the Mozilla Public |
| * License, v. 2.0. If a copy of the MPL was not distributed with this |
| * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| |
| #include "frontend/NameFunctions.h" |
| |
| #include "jsfun.h" |
| #include "jsprf.h" |
| |
| #include "frontend/BytecodeCompiler.h" |
| #include "frontend/ParseNode.h" |
| #include "frontend/SharedContext.h" |
| |
| #include "jsfuninlines.h" |
| |
| #include "vm/StringBuffer.h" |
| |
| using namespace js; |
| using namespace js::frontend; |
| |
| class NameResolver |
| { |
| static const size_t MaxParents = 100; |
| |
| JSContext *cx; |
| size_t nparents; /* number of parents in the parents array */ |
| ParseNode *parents[MaxParents]; /* history of ParseNodes we've been looking at */ |
| StringBuffer *buf; /* when resolving, buffer to append to */ |
| |
| /* Test whether a ParseNode represents a function invocation */ |
| bool call(ParseNode *pn) { |
| return pn && pn->isKind(PNK_CALL); |
| } |
| |
| /* |
| * Append a reference to a property named |name| to |buf|. If |name| is |
| * a proper identifier name, then we append '.name'; otherwise, we |
| * append '["name"]'. |
| * |
| * Note that we need the IsIdentifier check for atoms from both |
| * PNK_NAME nodes and PNK_STRING nodes: given code like a["b c"], the |
| * front end will produce a PNK_DOT with a PNK_NAME child whose name |
| * contains spaces. |
| */ |
| bool appendPropertyReference(JSAtom *name) { |
| if (IsIdentifier(name)) |
| return buf->append(".") && buf->append(name); |
| |
| /* Quote the string as needed. */ |
| JSString *source = js_QuoteString(cx, name, '"'); |
| return source && buf->append("[") && buf->append(source) && buf->append("]"); |
| } |
| |
| /* Append a number to buf. */ |
| bool appendNumber(double n) { |
| char number[30]; |
| int digits = JS_snprintf(number, sizeof(number), "%g", n); |
| return buf->appendInflated(number, digits); |
| } |
| |
| /* Append "[<n>]" to buf, referencing a property named by a numeric literal. */ |
| bool appendNumericPropertyReference(double n) { |
| return buf->append("[") && appendNumber(n) && buf->append("]"); |
| } |
| |
| /* |
| * Walk over the given ParseNode, converting it to a stringified name that |
| * respresents where the function is being assigned to. |
| */ |
| bool nameExpression(ParseNode *n) { |
| switch (n->getKind()) { |
| case PNK_DOT: |
| return nameExpression(n->expr()) && appendPropertyReference(n->pn_atom); |
| |
| case PNK_NAME: |
| return buf->append(n->pn_atom); |
| |
| case PNK_ELEM: |
| return nameExpression(n->pn_left) && |
| buf->append("[") && |
| nameExpression(n->pn_right) && |
| buf->append("]"); |
| |
| case PNK_NUMBER: |
| return appendNumber(n->pn_dval); |
| |
| default: |
| /* |
| * Technically this isn't an "abort" situation, we're just confused |
| * on what to call this function, but failures in naming aren't |
| * treated as fatal. |
| */ |
| return false; |
| } |
| } |
| |
| /* |
| * When naming an anonymous function, the process works loosely by walking |
| * up the AST and then translating that to a string. The stringification |
| * happens from some far-up assignment and then going back down the parse |
| * tree to the function definition point. |
| * |
| * This function will walk up the parse tree, gathering relevant nodes used |
| * for naming, and return the assignment node if there is one. The provided |
| * array and size will be filled in, and the returned node could be NULL if |
| * no assignment is found. The first element of the array will be the |
| * innermost node relevant to naming, and the last element will be the |
| * outermost node. |
| */ |
| ParseNode *gatherNameable(ParseNode **nameable, size_t *size) { |
| *size = 0; |
| |
| for (int pos = nparents - 1; pos >= 0; pos--) { |
| ParseNode *cur = parents[pos]; |
| if (cur->isAssignment()) |
| return cur; |
| |
| switch (cur->getKind()) { |
| case PNK_NAME: return cur; /* found the initialized declaration */ |
| case PNK_FUNCTION: return NULL; /* won't find an assignment or declaration */ |
| |
| case PNK_RETURN: |
| /* |
| * Normally the relevant parent of a node is its direct parent, but |
| * sometimes with code like: |
| * |
| * var foo = (function() { return function() {}; })(); |
| * |
| * the outer function is just a helper to create a scope for the |
| * returned function. Hence the name of the returned function should |
| * actually be 'foo'. This loop sees if the current node is a |
| * PNK_RETURN, and if there is a direct function call we skip to |
| * that. |
| */ |
| for (int tmp = pos - 1; tmp > 0; tmp--) { |
| if (isDirectCall(tmp, cur)) { |
| pos = tmp; |
| break; |
| } else if (call(cur)) { |
| /* Don't skip too high in the tree */ |
| break; |
| } |
| cur = parents[tmp]; |
| } |
| break; |
| |
| case PNK_COLON: |
| /* |
| * If this is a PNK_COLON, but our parent is not a PNK_OBJECT, |
| * then this is a label and we're done naming. Otherwise we |
| * record the PNK_COLON but skip the PNK_OBJECT so we're not |
| * flagged as a contributor. |
| */ |
| if (pos == 0 || !parents[pos - 1]->isKind(PNK_OBJECT)) |
| return NULL; |
| pos--; |
| /* fallthrough */ |
| |
| default: |
| /* Save any other nodes we encounter on the way up. */ |
| JS_ASSERT(*size < MaxParents); |
| nameable[(*size)++] = cur; |
| break; |
| } |
| } |
| |
| return NULL; |
| } |
| |
| /* |
| * Resolve the name of a function. If the function already has a name |
| * listed, then it is skipped. Otherwise an intelligent name is guessed to |
| * assign to the function's displayAtom field |
| */ |
| JSAtom *resolveFun(ParseNode *pn, HandleAtom prefix) { |
| JS_ASSERT(pn != NULL && pn->isKind(PNK_FUNCTION)); |
| RootedFunction fun(cx, pn->pn_funbox->function()); |
| |
| StringBuffer buf(cx); |
| this->buf = &buf; |
| |
| /* If the function already has a name, use that */ |
| if (fun->displayAtom() != NULL) { |
| if (prefix == NULL) |
| return fun->displayAtom(); |
| if (!buf.append(prefix) || |
| !buf.append("/") || |
| !buf.append(fun->displayAtom())) |
| return NULL; |
| return buf.finishAtom(); |
| } |
| |
| /* If a prefix is specified, then it is a form of namespace */ |
| if (prefix != NULL && (!buf.append(prefix) || !buf.append("/"))) |
| return NULL; |
| |
| /* Gather all nodes relevant to naming */ |
| ParseNode *toName[MaxParents]; |
| size_t size; |
| ParseNode *assignment = gatherNameable(toName, &size); |
| |
| /* If the function is assigned to something, then that is very relevant */ |
| if (assignment) { |
| if (assignment->isAssignment()) |
| assignment = assignment->pn_left; |
| if (!nameExpression(assignment)) |
| return NULL; |
| } |
| |
| /* |
| * Other than the actual assignment, other relevant nodes to naming are |
| * those in object initializers and then particular nodes marking a |
| * contribution. |
| */ |
| for (int pos = size - 1; pos >= 0; pos--) { |
| ParseNode *node = toName[pos]; |
| |
| if (node->isKind(PNK_COLON)) { |
| ParseNode *left = node->pn_left; |
| if (left->isKind(PNK_NAME) || left->isKind(PNK_STRING)) { |
| if (!appendPropertyReference(left->pn_atom)) |
| return NULL; |
| } else if (left->isKind(PNK_NUMBER)) { |
| if (!appendNumericPropertyReference(left->pn_dval)) |
| return NULL; |
| } |
| } else { |
| /* |
| * Don't have consecutive '<' characters, and also don't start |
| * with a '<' character. |
| */ |
| if (!buf.empty() && *(buf.end() - 1) != '<' && !buf.append("<")) |
| return NULL; |
| } |
| } |
| |
| /* |
| * functions which are "genuinely anonymous" but are contained in some |
| * other namespace are rather considered as "contributing" to the outer |
| * function, so give them a contribution symbol here. |
| */ |
| if (!buf.empty() && *(buf.end() - 1) == '/' && !buf.append("<")) |
| return NULL; |
| if (buf.empty()) |
| return NULL; |
| |
| JSAtom *atom = buf.finishAtom(); |
| if (!atom) |
| return NULL; |
| fun->setGuessedAtom(atom); |
| return atom; |
| } |
| |
| /* |
| * Tests whether parents[pos] is a function call whose callee is cur. |
| * This is the case for functions which do things like simply create a scope |
| * for new variables and then return an anonymous function using this scope. |
| */ |
| bool isDirectCall(int pos, ParseNode *cur) { |
| return pos >= 0 && call(parents[pos]) && parents[pos]->pn_head == cur; |
| } |
| |
| public: |
| explicit NameResolver(JSContext *cx) : cx(cx), nparents(0), buf(NULL) {} |
| |
| /* |
| * Resolve all names for anonymous functions recursively within the |
| * ParseNode instance given. The prefix is for each subsequent name, and |
| * should initially be NULL. |
| */ |
| void resolve(ParseNode *cur, HandleAtom prefixArg = NullPtr()) { |
| RootedAtom prefix(cx, prefixArg); |
| if (cur == NULL) |
| return; |
| |
| if (cur->isKind(PNK_FUNCTION) && cur->isArity(PN_CODE)) { |
| RootedAtom prefix2(cx, resolveFun(cur, prefix)); |
| /* |
| * If a function looks like (function(){})() where the parent node |
| * of the definition of the function is a call, then it shouldn't |
| * contribute anything to the namespace, so don't bother updating |
| * the prefix to whatever was returned. |
| */ |
| if (!isDirectCall(nparents - 1, cur)) |
| prefix = prefix2; |
| } |
| if (nparents >= MaxParents) |
| return; |
| parents[nparents++] = cur; |
| |
| switch (cur->getArity()) { |
| case PN_NULLARY: |
| break; |
| case PN_NAME: |
| resolve(cur->maybeExpr(), prefix); |
| break; |
| case PN_UNARY: |
| resolve(cur->pn_kid, prefix); |
| break; |
| case PN_BINARY: |
| resolve(cur->pn_left, prefix); |
| |
| /* |
| * FIXME? Occasionally pn_left == pn_right for something like |
| * destructuring assignment in (function({foo}){}), so skip the |
| * duplicate here if this is the case because we want to traverse |
| * everything at most once. |
| */ |
| if (cur->pn_left != cur->pn_right) |
| resolve(cur->pn_right, prefix); |
| break; |
| case PN_TERNARY: |
| resolve(cur->pn_kid1, prefix); |
| resolve(cur->pn_kid2, prefix); |
| resolve(cur->pn_kid3, prefix); |
| break; |
| case PN_CODE: |
| JS_ASSERT(cur->isKind(PNK_MODULE) || cur->isKind(PNK_FUNCTION)); |
| resolve(cur->pn_body, prefix); |
| break; |
| case PN_LIST: |
| for (ParseNode *nxt = cur->pn_head; nxt; nxt = nxt->pn_next) |
| resolve(nxt, prefix); |
| break; |
| } |
| nparents--; |
| } |
| }; |
| |
| bool |
| frontend::NameFunctions(JSContext *cx, ParseNode *pn) |
| { |
| NameResolver nr(cx); |
| nr.resolve(pn); |
| return true; |
| } |
