libdexfile/dex/class_accessor.h

/*
 * Copyright (C) 2018 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef ART_LIBDEXFILE_DEX_CLASS_ACCESSOR_H_
#define ART_LIBDEXFILE_DEX_CLASS_ACCESSOR_H_

#include "base/utils.h"
#include "code_item_accessors.h"
#include "dex_file.h"
#include "invoke_type.h"
#include "method_reference.h"
#include "modifiers.h"

namespace art {

class ClassIteratorData;

// Classes to access Dex data.
class ClassAccessor {
 private:
  class BaseItem {
   public:
    uint32_t GetIndex() const {
      return index_;
    }

    uint32_t GetAccessFlags() const {
      return access_flags_;
    }

    bool IsFinal() const {
      return (GetAccessFlags() & kAccFinal) != 0;
    }

   public:
    uint32_t index_ = 0u;
    uint32_t access_flags_ = 0u;
  };

 public:
  // A decoded version of the method of a class_data_item.
  class Method : public BaseItem {
   public:
    uint32_t GetCodeItemOffset() const {
      return code_off_;
    }

    InvokeType GetInvokeType(uint32_t class_access_flags) const {
      return is_static_or_direct_
          ? GetDirectMethodInvokeType()
          : GetVirtualMethodInvokeType(class_access_flags);
    }

    MethodReference GetReference() const {
      return MethodReference(&dex_file_, GetIndex());
    }

    CodeItemInstructionAccessor GetInstructions() const;

    const DexFile::CodeItem* GetCodeItem() const;

   private:
    explicit Method(const DexFile& dex_file, bool is_static_or_direct)
        : dex_file_(dex_file),
          is_static_or_direct_(is_static_or_direct) {}

    const uint8_t* Read(const uint8_t* ptr);

    InvokeType GetDirectMethodInvokeType() const {
      return (GetAccessFlags() & kAccStatic) != 0 ? kStatic : kDirect;
    }

    InvokeType GetVirtualMethodInvokeType(uint32_t class_access_flags) const {
      DCHECK_EQ(GetAccessFlags() & kAccStatic, 0U);
      if ((class_access_flags & kAccInterface) != 0) {
        return kInterface;
      } else if ((GetAccessFlags() & kAccConstructor) != 0) {
        return kSuper;
      } else {
        return kVirtual;
      }
    }

    const DexFile& dex_file_;
    const bool is_static_or_direct_;
    uint32_t code_off_ = 0u;

    friend class ClassAccessor;
  };

  // A decoded version of the field of a class_data_item.
  class Field : public BaseItem {
   private:
    const uint8_t* Read(const uint8_t* ptr);

    friend class ClassAccessor;
  };

  // Not explicit specifically for range-based loops.
  ALWAYS_INLINE ClassAccessor(const ClassIteratorData& data);

  ClassAccessor(const DexFile& dex_file, const DexFile::ClassDef& class_def);

  // Return the code item for a method.
  const DexFile::CodeItem* GetCodeItem(const Method& method) const;

  // Iterator data is not very iterator friendly, use visitors to get around this.
  // No thread safety analysis since the visitor may require capabilities.
  template <typename StaticFieldVisitor,
            typename InstanceFieldVisitor,
            typename DirectMethodVisitor,
            typename VirtualMethodVisitor>
  void VisitFieldsAndMethods(const StaticFieldVisitor& static_field_visitor,
                             const InstanceFieldVisitor& instance_field_visitor,
                             const DirectMethodVisitor& direct_method_visitor,
                             const VirtualMethodVisitor& virtual_method_visitor) const
      NO_THREAD_SAFETY_ANALYSIS;

  template <typename DirectMethodVisitor,
            typename VirtualMethodVisitor>
  void VisitMethods(const DirectMethodVisitor& direct_method_visitor,
                    const VirtualMethodVisitor& virtual_method_visitor) const;

  template <typename StaticFieldVisitor,
            typename InstanceFieldVisitor>
  void VisitFields(const StaticFieldVisitor& static_field_visitor,
                   const InstanceFieldVisitor& instance_field_visitor) const;

  // Visit direct and virtual methods.
  template <typename MethodVisitor>
  void VisitMethods(const MethodVisitor& method_visitor) const;

  uint32_t NumStaticFields() const {
    return num_static_fields_;
  }

  uint32_t NumInstanceFields() const {
    return num_instance_fields_;
  }

  uint32_t NumDirectMethods() const {
    return num_direct_methods_;
  }

  uint32_t NumVirtualMethods() const {
    return num_virtual_methods_;
  }

  const char* GetDescriptor() const;

  dex::TypeIndex GetClassIdx() const {
    return descriptor_index_;
  }

  const DexFile& GetDexFile() const {
    return dex_file_;
  }

 protected:
  const DexFile& dex_file_;
  const dex::TypeIndex descriptor_index_ = {};
  const uint8_t* ptr_pos_ = nullptr;  // Pointer into stream of class_data_item.
  const uint32_t num_static_fields_ = 0u;
  const uint32_t num_instance_fields_ = 0u;
  const uint32_t num_direct_methods_ = 0u;
  const uint32_t num_virtual_methods_ = 0u;
};

}  // namespace art

#endif  // ART_LIBDEXFILE_DEX_CLASS_ACCESSOR_H_