The Tor Browser: dom/system/gonk/Volume.cpp@6474c204b198 (annotated)

dom/system/gonk/Volume.cpp@6474c204b198 (annotated)

dom/system/gonk/Volume.cpp

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "Volume.h"
 #include "VolumeCommand.h"
 #include "VolumeManager.h"
 #include "VolumeManagerLog.h"
 #include "nsIVolume.h"
 #include "nsXULAppAPI.h"
 #include <vold/ResponseCode.h>
 namespace mozilla {
 namespace system {
 Volume::EventObserverList Volume::mEventObserverList;
 // We have a feature where volumes can be locked when mounted. This
 // is used to prevent a volume from being shared with the PC while
 // it is actively being used (say for storing an update image)
 //
 // We use WakeLocks (a poor choice of name, but it does what we want)
 // from the PowerManagerService to determine when we're locked.
 // In particular we'll create a wakelock called volume-NAME-GENERATION
 // (where NAME is the volume name, and GENERATION is its generation
 // number), and if this wakelock is locked, then we'll prevent a volume
 // from being shared.
 //
 // Implementation Details:
 //
 // Since the AutoMounter can only control when something gets mounted
 // and not when it gets unmounted (for example: a user pulls the SDCard)
 // and because Volume and nsVolume data structures are maintained on
 // separate threads, we have the potential for some race conditions.
 // We eliminate the race conditions by introducing the concept of a
 // generation number. Every time a volume transitions to the Mounted
 // state, it gets assigned a new generation number. Whenever the state
 // of a Volume changes, we send the updated state and current generation
 // number to the main thread where it gets updated in the nsVolume.
 //
 // Since WakeLocks can only be queried from the main-thread, the
 // nsVolumeService looks for WakeLock status changes, and forwards
 // the results to the IOThread.
 //
 // If the Volume (IOThread) recieves a volume update where the generation
 // number mismatches, then the update is simply ignored.
 //
 // When a Volume (IOThread) initially becomes mounted, we assume it to
 // be locked until we get our first update from nsVolume (MainThread).
 static int32_t sMountGeneration = 0;
 // We don't get media inserted/removed events at startup. So we
 // assume it's present, and we'll be told that it's missing.
 Volume::Volume(const nsCSubstring& aName)
   : mMediaPresent(true),
     mState(nsIVolume::STATE_INIT),
     mName(aName),
     mMountGeneration(-1),
     mMountLocked(true),  // Needs to agree with nsVolume::nsVolume
     mSharingEnabled(false),
     mCanBeShared(true),
     mIsSharing(false),
     mFormatRequested(false),
     mMountRequested(false),
     mUnmountRequested(false),
     mIsFormatting(false)
 {
   DBG("Volume %s: created", NameStr());
 }
 void
 Volume::SetIsSharing(bool aIsSharing)
 {
   if (aIsSharing == mIsSharing) {
     return;
   }
   mIsSharing = aIsSharing;
   LOG("Volume %s: IsSharing set to %d state %s",
       NameStr(), (int)mIsSharing, StateStr(mState));
   if (mIsSharing) {
     mEventObserverList.Broadcast(this);
   }
 }
 void
 Volume::SetIsFormatting(bool aIsFormatting)
 {
   if (aIsFormatting == mIsFormatting) {
     return;
   }
   mIsFormatting = aIsFormatting;
   LOG("Volume %s: IsFormatting set to %d state %s",
       NameStr(), (int)mIsFormatting, StateStr(mState));
   if (mIsFormatting) {
     mEventObserverList.Broadcast(this);
   }
 }
 void
 Volume::SetMediaPresent(bool aMediaPresent)
 {
   MOZ_ASSERT(XRE_GetProcessType() == GeckoProcessType_Default);
   MOZ_ASSERT(MessageLoop::current() == XRE_GetIOMessageLoop());
   // mMediaPresent is slightly redunant to the state, however
   // when media is removed (while Idle), we get the following:
   //    631 Volume sdcard /mnt/sdcard disk removed (179:0)
   //    605 Volume sdcard /mnt/sdcard state changed from 1 (Idle-Unmounted) to 0 (No-Media)
   //
   // And on media insertion, we get:
   //    630 Volume sdcard /mnt/sdcard disk inserted (179:0)
   //    605 Volume sdcard /mnt/sdcard state changed from 0 (No-Media) to 2 (Pending)
   //    605 Volume sdcard /mnt/sdcard state changed from 2 (Pending) to 1 (Idle-Unmounted)
   //
   // On media removal while the media is mounted:
   //    632 Volume sdcard /mnt/sdcard bad removal (179:1)
   //    605 Volume sdcard /mnt/sdcard state changed from 4 (Mounted) to 5 (Unmounting)
   //    605 Volume sdcard /mnt/sdcard state changed from 5 (Unmounting) to 1 (Idle-Unmounted)
   //    631 Volume sdcard /mnt/sdcard disk removed (179:0)
   //    605 Volume sdcard /mnt/sdcard state changed from 1 (Idle-Unmounted) to 0 (No-Media)
   //
   // When sharing with a PC, it goes Mounted -> Idle -> Shared
   // When unsharing with a PC, it goes Shared -> Idle -> Mounted
   //
   // The AutoMounter needs to know whether the media is present or not when
   // processing the Idle state.
   if (mMediaPresent == aMediaPresent) {
     return;
   }
   LOG("Volume: %s media %s", NameStr(), aMediaPresent ? "inserted" : "removed");
   mMediaPresent = aMediaPresent;
   mEventObserverList.Broadcast(this);
 }
 void
 Volume::SetSharingEnabled(bool aSharingEnabled)
 {
   mSharingEnabled = aSharingEnabled;
   LOG("SetSharingMode for volume %s to %d canBeShared = %d",
       NameStr(), (int)mSharingEnabled, (int)mCanBeShared);
 }
 void
 Volume::SetFormatRequested(bool aFormatRequested)
 {
   mFormatRequested = aFormatRequested;
   LOG("SetFormatRequested for volume %s to %d CanBeFormatted = %d",
       NameStr(), (int)mFormatRequested, (int)CanBeFormatted());
 }
 void
 Volume::SetMountRequested(bool aMountRequested)
 {
   mMountRequested = aMountRequested;
   LOG("SetMountRequested for volume %s to %d CanBeMounted = %d",
       NameStr(), (int)mMountRequested, (int)CanBeMounted());
 }
 void
 Volume::SetUnmountRequested(bool aUnmountRequested)
 {
   mUnmountRequested = aUnmountRequested;
   LOG("SetUnmountRequested for volume %s to %d CanBeMounted = %d",
       NameStr(), (int)mUnmountRequested, (int)CanBeMounted());
 }
 void
 Volume::SetState(Volume::STATE aNewState)
 {
   MOZ_ASSERT(XRE_GetProcessType() == GeckoProcessType_Default);
   MOZ_ASSERT(MessageLoop::current() == XRE_GetIOMessageLoop());
   if (aNewState == mState) {
     return;
   }
   if (aNewState == nsIVolume::STATE_MOUNTED) {
     mMountGeneration = ++sMountGeneration;
     LOG("Volume %s: changing state from %s to %s @ '%s' (%d observers) "
         "mountGeneration = %d, locked = %d",
         NameStr(), StateStr(mState),
         StateStr(aNewState), mMountPoint.get(), mEventObserverList.Length(),
         mMountGeneration, (int)mMountLocked);
   } else {
     LOG("Volume %s: changing state from %s to %s (%d observers)",
         NameStr(), StateStr(mState),
         StateStr(aNewState), mEventObserverList.Length());
   }
   switch (aNewState) {
      case nsIVolume::STATE_NOMEDIA:
        // Cover the startup case where we don't get insertion/removal events
        mMediaPresent = false;
        mIsSharing = false;
        mUnmountRequested = false;
        mMountRequested = false;
        break;
      case nsIVolume::STATE_MOUNTED:
        mMountRequested = false;
        mIsFormatting = false;
        mIsSharing = false;
        break;
      case nsIVolume::STATE_FORMATTING:
        mFormatRequested = false;
        mIsFormatting = true;
        mIsSharing = false;
        break;
      case nsIVolume::STATE_SHARED:
      case nsIVolume::STATE_SHAREDMNT:
        // Covers startup cases. Normally, mIsSharing would be set to true
        // when we issue the command to initiate the sharing process, but
        // it's conceivable that a volume could already be in a shared state
        // when b2g starts.
        mIsSharing = true;
        break;
      case nsIVolume::STATE_IDLE:
        break;
      default:
        break;
   }
   mState = aNewState;
   mEventObserverList.Broadcast(this);
 }
 void
 Volume::SetMountPoint(const nsCSubstring& aMountPoint)
 {
   MOZ_ASSERT(XRE_GetProcessType() == GeckoProcessType_Default);
   MOZ_ASSERT(MessageLoop::current() == XRE_GetIOMessageLoop());
   if (mMountPoint.Equals(aMountPoint)) {
     return;
   }
   mMountPoint = aMountPoint;
   DBG("Volume %s: Setting mountpoint to '%s'", NameStr(), mMountPoint.get());
 }
 void
 Volume::StartMount(VolumeResponseCallback* aCallback)
 {
   MOZ_ASSERT(XRE_GetProcessType() == GeckoProcessType_Default);
   MOZ_ASSERT(MessageLoop::current() == XRE_GetIOMessageLoop());
   StartCommand(new VolumeActionCommand(this, "mount", "", aCallback));
 }
 void
 Volume::StartUnmount(VolumeResponseCallback* aCallback)
 {
   MOZ_ASSERT(XRE_GetProcessType() == GeckoProcessType_Default);
   MOZ_ASSERT(MessageLoop::current() == XRE_GetIOMessageLoop());
   StartCommand(new VolumeActionCommand(this, "unmount", "force", aCallback));
 }
 void
 Volume::StartFormat(VolumeResponseCallback* aCallback)
 {
   MOZ_ASSERT(XRE_GetProcessType() == GeckoProcessType_Default);
   MOZ_ASSERT(MessageLoop::current() == XRE_GetIOMessageLoop());
   StartCommand(new VolumeActionCommand(this, "format", "", aCallback));
 }
 void
 Volume::StartShare(VolumeResponseCallback* aCallback)
 {
   MOZ_ASSERT(XRE_GetProcessType() == GeckoProcessType_Default);
   MOZ_ASSERT(MessageLoop::current() == XRE_GetIOMessageLoop());
   StartCommand(new VolumeActionCommand(this, "share", "ums", aCallback));
 }
 void
 Volume::StartUnshare(VolumeResponseCallback* aCallback)
 {
   MOZ_ASSERT(XRE_GetProcessType() == GeckoProcessType_Default);
   MOZ_ASSERT(MessageLoop::current() == XRE_GetIOMessageLoop());
   StartCommand(new VolumeActionCommand(this, "unshare", "ums", aCallback));
 }
 void
 Volume::StartCommand(VolumeCommand* aCommand)
 {
   MOZ_ASSERT(XRE_GetProcessType() == GeckoProcessType_Default);
   MOZ_ASSERT(MessageLoop::current() == XRE_GetIOMessageLoop());
   VolumeManager::PostCommand(aCommand);
 }
 //static
 void
 Volume::RegisterObserver(Volume::EventObserver* aObserver)
 {
   MOZ_ASSERT(XRE_GetProcessType() == GeckoProcessType_Default);
   MOZ_ASSERT(MessageLoop::current() == XRE_GetIOMessageLoop());
   mEventObserverList.AddObserver(aObserver);
   // Send an initial event to the observer (for each volume)
   size_t numVolumes = VolumeManager::NumVolumes();
   for (size_t volIndex = 0; volIndex < numVolumes; volIndex++) {
     RefPtr<Volume> vol = VolumeManager::GetVolume(volIndex);
     aObserver->Notify(vol);
   }
 }
 //static
 void
 Volume::UnregisterObserver(Volume::EventObserver* aObserver)
 {
   MOZ_ASSERT(XRE_GetProcessType() == GeckoProcessType_Default);
   MOZ_ASSERT(MessageLoop::current() == XRE_GetIOMessageLoop());
   mEventObserverList.RemoveObserver(aObserver);
 }
 //static
 void
 Volume::UpdateMountLock(const nsACString& aVolumeName,
                         const int32_t& aMountGeneration,
                         const bool& aMountLocked)
 {
   MOZ_ASSERT(XRE_GetProcessType() == GeckoProcessType_Default);
   MOZ_ASSERT(MessageLoop::current() == XRE_GetIOMessageLoop());
   RefPtr<Volume> vol = VolumeManager::FindVolumeByName(aVolumeName);
   if (!vol || (vol->mMountGeneration != aMountGeneration)) {
     return;
   }
   if (vol->mMountLocked != aMountLocked) {
     vol->mMountLocked = aMountLocked;
     DBG("Volume::UpdateMountLock for '%s' to %d\n", vol->NameStr(), (int)aMountLocked);
     mEventObserverList.Broadcast(vol);
   }
 }
 void
 Volume::HandleVoldResponse(int aResponseCode, nsCWhitespaceTokenizer& aTokenizer)
 {
   MOZ_ASSERT(XRE_GetProcessType() == GeckoProcessType_Default);
   MOZ_ASSERT(MessageLoop::current() == XRE_GetIOMessageLoop());
   // The volume name will have already been parsed, and the tokenizer will point
   // to the token after the volume name
   switch (aResponseCode) {
     case ResponseCode::VolumeListResult: {
       // Each line will look something like:
       //
       //  sdcard /mnt/sdcard 1
       //
       nsDependentCSubstring mntPoint(aTokenizer.nextToken());
       SetMountPoint(mntPoint);
       nsresult errCode;
       nsCString state(aTokenizer.nextToken());
       if (state.EqualsLiteral("X")) {
         // Special state for creating fake volumes which can't be shared.
         mCanBeShared = false;
         SetState(nsIVolume::STATE_MOUNTED);
       } else {
         SetState((STATE)state.ToInteger(&errCode));
       }
       break;
     }
     case ResponseCode::VolumeStateChange: {
       // Format of the line looks something like:
       //
       //  Volume sdcard /mnt/sdcard state changed from 7 (Shared-Unmounted) to 1 (Idle-Unmounted)
       //
       // So we parse out the state after the string " to "
       while (aTokenizer.hasMoreTokens()) {
         nsAutoCString token(aTokenizer.nextToken());
         if (token.Equals("to")) {
           nsresult errCode;
           token = aTokenizer.nextToken();
           SetState((STATE)token.ToInteger(&errCode));
           break;
         }
       }
       break;
     }
     case ResponseCode::VolumeDiskInserted:
       SetMediaPresent(true);
       break;
     case ResponseCode::VolumeDiskRemoved: // fall-thru
     case ResponseCode::VolumeBadRemoval:
       SetMediaPresent(false);
       break;
     default:
       LOG("Volume: %s unrecognized reponse code (ignored)", NameStr());
       break;
   }
 }
 } // namespace system
 } // namespace mozilla

The Tor Browser / annotate

dom/system/gonk/Volume.cpp@6474c204b198 (annotated)

dom/system/gonk/Volume.cpp