775106 - Migrate RwAutoLockRead/Write class wrappers for PR_RWLock*() from dom/camera/GonkCameraControl.cpp

Status: RESOLVED WONTFIX

(Core :: MFBT, defect)

Description

[Mike Habicher [:mikeh] (high bugzilla latency)]

Implemented this for DOM camera support:

class RwAutoLockRead
{
public:
  RwAutoLockRead(PRRWLock* aRwLock)
    : mRwLock(aRwLock)
  {
    PR_RWLock_Rlock(mRwLock);
  }

  ~RwAutoLockRead()
  {
    PR_RWLock_Unlock(mRwLock);
  }

protected:
  PRRWLock *mRwLock;
};

class RwAutoLockWrite
{
public:
  RwAutoLockWrite(PRRWLock* aRwLock)
    : mRwLock(aRwLock)
  {
    PR_RWLock_Wlock(mRwLock);
  }

  ~RwAutoLockWrite()
  {
    PR_RWLock_Unlock(mRwLock);
  }

protected:
  PRRWLock *mRwLock;
};

May be useful to others, should migrate to a more useful location once DOM camera supports lands.

Comment 1

[Mike Habicher [:mikeh] (high bugzilla latency)]

(In reply to Mike Habicher [:mikeh] from comment #0)

> May be useful to others, should migrate to a more useful location once DOM
> camera supports lands.

*support.

Comment 2

[Mike Hommey [:glandium]]

What use does that have, when you have a separate class for read and write lock?

Anyways, this should be implemented on top of bug 773491

Comment 3

[Mike Habicher [:mikeh] (high bugzilla latency)]

(In reply to Mike Hommey [:glandium] from comment #2)
> What use does that have, when you have a separate class for read and write lock?

They both operate on the same lock (created elsewhere), but give the lock the usual C++ scope management.

Comment 4

[Simon Giesecke [:sg] [he/him]]

As of now, there aren't any uses of PR_RWLock* in C++ code, so I guess we don't need this anymore.