webrtc源码走读之base

src/webrtc/base是webrtc基础平台库，包括线程、锁、socket,智能指针等.

智能指针

refcount.h定义了rtc::RefCountInterface:

#include "webrtc/base/refcountedobject.h"

namespace rtc {

// Reference count interface.
class RefCountInterface {
 public:
  virtual int AddRef() const = 0;
  virtual int Release() const = 0;

 protected:
  virtual ~RefCountInterface() {}
};

}  // namespace rtc

refcountedobject.h下定义了RefCountedObject:

#include <utility>

#include "webrtc/base/atomicops.h"

namespace rtc {

template <class T>
class RefCountedObject : public T {
 public:
  RefCountedObject() {}

  template <class P0>
  explicit RefCountedObject(P0&& p0) : T(std::forward<P0>(p0)) {}

  template <class P0, class P1, class... Args>
  RefCountedObject(P0&& p0, P1&& p1, Args&&... args)
      : T(std::forward<P0>(p0),
          std::forward<P1>(p1),
          std::forward<Args>(args)...) {}

  virtual int AddRef() const { return AtomicOps::Increment(&ref_count_); }

  virtual int Release() const {
    int count = AtomicOps::Decrement(&ref_count_);
    if (!count) {
      delete this;
    }
    return count;
  }

  // Return whether the reference count is one. If the reference count is used
  // in the conventional way, a reference count of 1 implies that the current
  // thread owns the reference and no other thread shares it. This call
  // performs the test for a reference count of one, and performs the memory
  // barrier needed for the owning thread to act on the object, knowing that it
  // has exclusive access to the object.
  virtual bool HasOneRef() const {
    return AtomicOps::AcquireLoad(&ref_count_) == 1;
  }

 protected:
  virtual ~RefCountedObject() {}

  mutable volatile int ref_count_ = 0;
};

}  // namespace rtc

线程Thread

网络Socket