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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 class Isolate;
     35 
     36 // FuncNameInferrer is a stateful class that is used to perform name
     37 // inference for anonymous functions during static analysis of source code.
     38 // Inference is performed in cases when an anonymous function is assigned
     39 // to a variable or a property (see test-func-name-inference.cc for examples.)
     40 //
     41 // The basic idea is that during parsing of LHSs of certain expressions
     42 // (assignments, declarations, object literals) we collect name strings,
     43 // and during parsing of the RHS, a function literal can be collected. After
     44 // parsing the RHS we can infer a name for function literals that do not have
     45 // a name.
     46 class FuncNameInferrer : public ZoneObject {
     47  public:
     48   explicit FuncNameInferrer(Isolate* isolate);
     49 
     50   // Returns whether we have entered name collection state.
     51   bool IsOpen() const { return !entries_stack_.is_empty(); }
     52 
     53   // Pushes an enclosing the name of enclosing function onto names stack.
     54   void PushEnclosingName(Handle<String> name);
     55 
     56   // Enters name collection state.
     57   void Enter() {
     58     entries_stack_.Add(names_stack_.length());
     59   }
     60 
     61   // Pushes an encountered name onto names stack when in collection state.
     62   void PushLiteralName(Handle<String> name);
     63 
     64   void PushVariableName(Handle<String> name);
     65 
     66   // Adds a function to infer name for.
     67   void AddFunction(FunctionLiteral* func_to_infer) {
     68     if (IsOpen()) {
     69       funcs_to_infer_.Add(func_to_infer);
     70     }
     71   }
     72 
     73   void RemoveLastFunction() {
     74     if (IsOpen() && !funcs_to_infer_.is_empty()) {
     75       funcs_to_infer_.RemoveLast();
     76     }
     77   }
     78 
     79   // Infers a function name and leaves names collection state.
     80   void Infer() {
     81     ASSERT(IsOpen());
     82     if (!funcs_to_infer_.is_empty()) {
     83       InferFunctionsNames();
     84     }
     85   }
     86 
     87   // Leaves names collection state.
     88   void Leave() {
     89     ASSERT(IsOpen());
     90     names_stack_.Rewind(entries_stack_.RemoveLast());
     91   }
     92 
     93  private:
     94   enum NameType {
     95     kEnclosingConstructorName,
     96     kLiteralName,
     97     kVariableName
     98   };
     99   struct Name {
    100     Name(Handle<String> name, NameType type) : name(name), type(type) { }
    101     Handle<String> name;
    102     NameType type;
    103   };
    104 
    105   Isolate* isolate() { return isolate_; }
    106 
    107   // Constructs a full name in dotted notation from gathered names.
    108   Handle<String> MakeNameFromStack();
    109 
    110   // A helper function for MakeNameFromStack.
    111   Handle<String> MakeNameFromStackHelper(int pos, Handle<String> prev);
    112 
    113   // Performs name inferring for added functions.
    114   void InferFunctionsNames();
    115 
    116   Isolate* isolate_;
    117   ZoneList<int> entries_stack_;
    118   ZoneList<Name> names_stack_;
    119   ZoneList<FunctionLiteral*> funcs_to_infer_;
    120 
    121   DISALLOW_COPY_AND_ASSIGN(FuncNameInferrer);
    122 };
    123 
    124 
    125 } }  // namespace v8::internal
    126 
    127 #endif  // V8_FUNC_NAME_INFERRER_H_
    128