The Tor Browser: js/src/frontend/NameFunctions.cpp@129ffea94266 (annotated)

js/src/frontend/NameFunctions.cpp@129ffea94266 (annotated)

js/src/frontend/NameFunctions.cpp

Sat, 03 Jan 2015 20:18:00 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Sat, 03 Jan 2015 20:18:00 +0100
branch: TOR_BUG_3246
changeset 7: 129ffea94266
permissions: -rw-r--r--

Conditionally enable double key logic according to:
private browsing mode or privacy.thirdparty.isolate preference and
implement in GetCookieStringCommon and FindCookie where it counts...
With some reservations of how to convince FindCookie users to test
condition and pass a nullptr when disabling double key logic.

 /* -*- 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 "vm/StringBuffer.h"
 using namespace js;
 using namespace js::frontend;
 namespace {
 class NameResolver
 {
     static const size_t MaxParents = 100;
     ExclusiveContext *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_THIS:
             return buf->append("this");
           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 nullptr
      * 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_THIS:     return cur;  /* Setting a property of 'this'. */
               case PNK_FUNCTION: return nullptr; /* 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:
                 /*
                  * Record the PNK_COLON but skip the PNK_OBJECT so we're not
                  * flagged as a contributor.
                  */
                 pos--;
                 /* fallthrough */
               default:
                 /* Save any other nodes we encounter on the way up. */
                 JS_ASSERT(*size < MaxParents);
                 nameable[(*size)++] = cur;
                 break;
             }
         }
         return nullptr;
     }
     /*
      * 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
      */
     bool resolveFun(ParseNode *pn, HandleAtom prefix, MutableHandleAtom retAtom) {
         JS_ASSERT(pn != nullptr && pn->isKind(PNK_FUNCTION));
         RootedFunction fun(cx, pn->pn_funbox->function());
         StringBuffer buf(cx);
         this->buf = &buf;
         retAtom.set(nullptr);
         /* If the function already has a name, use that */
         if (fun->displayAtom() != nullptr) {
             if (prefix == nullptr) {
                 retAtom.set(fun->displayAtom());
                 return true;
             }
             if (!buf.append(prefix) ||
                 !buf.append("/") ||
                 !buf.append(fun->displayAtom()))
                 return false;
             retAtom.set(buf.finishAtom());
             return !!retAtom;
         }
         /* If a prefix is specified, then it is a form of namespace */
         if (prefix != nullptr && (!buf.append(prefix) || !buf.append("/")))
             return false;
         /* 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 true;
         }
         /*
          * 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 false;
                 } else if (left->isKind(PNK_NUMBER)) {
                     if (!appendNumericPropertyReference(left->pn_dval))
                         return false;
                 }
             } else {
                 /*
                  * Don't have consecutive '<' characters, and also don't start
                  * with a '<' character.
                  */
                 if (!buf.empty() && *(buf.end() - 1) != '<' && !buf.append("<"))
                     return false;
             }
         }
         /*
          * 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 false;
         if (buf.empty())
             return true;
         retAtom.set(buf.finishAtom());
         if (!retAtom)
             return false;
         fun->setGuessedAtom(retAtom);
         return true;
     }
     /*
      * 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(ExclusiveContext *cx) : cx(cx), nparents(0), buf(nullptr) {}
     /*
      * Resolve all names for anonymous functions recursively within the
      * ParseNode instance given. The prefix is for each subsequent name, and
      * should initially be nullptr.
      */
     bool resolve(ParseNode *cur, HandleAtom prefixArg = js::NullPtr()) {
         RootedAtom prefix(cx, prefixArg);
         if (cur == nullptr)
             return true;
         if (cur->isKind(PNK_FUNCTION) && cur->isArity(PN_CODE)) {
             RootedAtom prefix2(cx);
             if (!resolveFun(cur, prefix, &prefix2))
                 return false;
             /*
              * 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 true;
         parents[nparents++] = cur;
         switch (cur->getArity()) {
           case PN_NULLARY:
             break;
           case PN_NAME:
             if (!resolve(cur->maybeExpr(), prefix))
                 return false;
             break;
           case PN_UNARY:
             if (!resolve(cur->pn_kid, prefix))
                 return false;
             break;
           case PN_BINARY:
           case PN_BINARY_OBJ:
             if (!resolve(cur->pn_left, prefix))
                 return false;
             /*
              * 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)
                 if (!resolve(cur->pn_right, prefix))
                     return false;
             break;
           case PN_TERNARY:
             if (!resolve(cur->pn_kid1, prefix))
                 return false;
             if (!resolve(cur->pn_kid2, prefix))
                 return false;
             if (!resolve(cur->pn_kid3, prefix))
                 return false;
             break;
           case PN_CODE:
             JS_ASSERT(cur->isKind(PNK_FUNCTION));
             if (!resolve(cur->pn_body, prefix))
                 return false;
             break;
           case PN_LIST:
             for (ParseNode *nxt = cur->pn_head; nxt; nxt = nxt->pn_next)
                 if (!resolve(nxt, prefix))
                     return false;
             break;
         }
         nparents--;
         return true;
     }
 };
 } /* anonymous namespace */
 bool
 frontend::NameFunctions(ExclusiveContext *cx, ParseNode *pn)
 {
     NameResolver nr(cx);
     return nr.resolve(pn);
 }

The Tor Browser / annotate

js/src/frontend/NameFunctions.cpp@129ffea94266 (annotated)

js/src/frontend/NameFunctions.cpp