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      1 // Copyright 2006-2009 the V8 project authors. All rights reserved.
      2 // Redistribution and use in source and binary forms, with or without
      3 // modification, are permitted provided that the following conditions are
      4 // met:
      5 //
      6 //     * Redistributions of source code must retain the above copyright
      7 //       notice, this list of conditions and the following disclaimer.
      8 //     * Redistributions in binary form must reproduce the above
      9 //       copyright notice, this list of conditions and the following
     10 //       disclaimer in the documentation and/or other materials provided
     11 //       with the distribution.
     12 //     * Neither the name of Google Inc. nor the names of its
     13 //       contributors may be used to endorse or promote products derived
     14 //       from this software without specific prior written permission.
     15 //
     16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27 
     28 #ifndef V8_FUNC_NAME_INFERRER_H_
     29 #define V8_FUNC_NAME_INFERRER_H_
     30 
     31 namespace v8 {
     32 namespace internal {
     33 
     34 // FuncNameInferrer is a stateful class that is used to perform name
     35 // inference for anonymous functions during static analysis of source code.
     36 // Inference is performed in cases when an anonymous function is assigned
     37 // to a variable or a property (see test-func-name-inference.cc for examples.)
     38 //
     39 // The basic idea is that during parsing of LHSs of certain expressions
     40 // (assignments, declarations, object literals) we collect name strings,
     41 // and during parsing of the RHS, a function literal can be collected. After
     42 // parsing the RHS we can infer a name for function literals that do not have
     43 // a name.
     44 class FuncNameInferrer : public ZoneObject {
     45  public:
     46   FuncNameInferrer()
     47       : entries_stack_(10),
     48         names_stack_(5),
     49         funcs_to_infer_(4),
     50         dot_(FACTORY->NewStringFromAscii(CStrVector("."))) {
     51   }
     52 
     53   // Returns whether we have entered name collection state.
     54   bool IsOpen() const { return !entries_stack_.is_empty(); }
     55 
     56   // Pushes an enclosing the name of enclosing function onto names stack.
     57   void PushEnclosingName(Handle<String> name);
     58 
     59   // Enters name collection state.
     60   void Enter() {
     61     entries_stack_.Add(names_stack_.length());
     62   }
     63 
     64   // Pushes an encountered name onto names stack when in collection state.
     65   void PushLiteralName(Handle<String> name);
     66 
     67   void PushVariableName(Handle<String> name);
     68 
     69   // Adds a function to infer name for.
     70   void AddFunction(FunctionLiteral* func_to_infer) {
     71     if (IsOpen()) {
     72       funcs_to_infer_.Add(func_to_infer);
     73     }
     74   }
     75 
     76   // Infers a function name and leaves names collection state.
     77   void Infer() {
     78     ASSERT(IsOpen());
     79     if (!funcs_to_infer_.is_empty()) {
     80       InferFunctionsNames();
     81     }
     82   }
     83 
     84   // Infers a function name and leaves names collection state.
     85   void Leave() {
     86     ASSERT(IsOpen());
     87     names_stack_.Rewind(entries_stack_.RemoveLast());
     88   }
     89 
     90  private:
     91   // Constructs a full name in dotted notation from gathered names.
     92   Handle<String> MakeNameFromStack();
     93 
     94   // A helper function for MakeNameFromStack.
     95   Handle<String> MakeNameFromStackHelper(int pos, Handle<String> prev);
     96 
     97   // Performs name inferring for added functions.
     98   void InferFunctionsNames();
     99 
    100   ZoneList<int> entries_stack_;
    101   ZoneList<Handle<String> > names_stack_;
    102   ZoneList<FunctionLiteral*> funcs_to_infer_;
    103   Handle<String> dot_;
    104 
    105   DISALLOW_COPY_AND_ASSIGN(FuncNameInferrer);
    106 };
    107 
    108 
    109 } }  // namespace v8::internal
    110 
    111 #endif  // V8_FUNC_NAME_INFERRER_H_
    112