Stop using base-class's lock

tshino · Dec 26, 2023 · a3b1f35 · a3b1f35
1 parent 83de162
commit a3b1f35
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Showing 3 changed files with 41 additions and 2 deletions.
diff --git a/src/softcamcore/DShowSoftcam.cpp b/src/softcamcore/DShowSoftcam.cpp
@@ -368,7 +368,7 @@ FrameBuffer* Softcam::getFrameBuffer()
         return nullptr;
     }
 
-    CAutoLock lock(&m_cStateLock);
+    CAutoLock lock(&m_critsec);
     if (!m_frame_buffer)
     {
         auto fb = FrameBuffer::open();
@@ -393,7 +393,7 @@ FrameBuffer* Softcam::getFrameBuffer()
 void
 Softcam::releaseFrameBuffer()
 {
-    CAutoLock lock(&m_cStateLock);
+    CAutoLock lock(&m_critsec);
     m_frame_buffer.release();
 }
 

diff --git a/src/softcamcore/DShowSoftcam.h b/src/softcamcore/DShowSoftcam.h
@@ -41,6 +41,7 @@ class Softcam : public CSource, public IAMStreamConfig
     static void     disableDefaultBlankImage();
 
 private:
+    CCritSec    m_critsec;
     FrameBuffer m_frame_buffer;
     DefaultImage m_default_image;
     const bool  m_valid;

diff --git a/tests/core_tests/DShowSoftcamTest.cpp b/tests/core_tests/DShowSoftcamTest.cpp
@@ -1003,5 +1003,43 @@ TEST_F(SoftcamStream, CSourceStreamGetMediaTypeNormal)
     checkMediaType320x240(&mt);
 }
 
+TEST_F(SoftcamStream, getFrameBuffer_must_not_lock_the_filter_state)
+{
+    auto fb = createFrameBufer(320, 240, 60);
+    SetUpSoftcamStream();
+
+    CAutoLock lock(m_softcam->pStateLock()); // 1st lock
+    std::atomic<int> done{false};
+    std::thread th([&]
+    {
+        // A deadlock occurs if this code attempts to get lock.
+        m_softcam->getFrameBuffer();
+        done = true;
+    });
+
+    for (int i = 0; !done && i < 20; i++) { sc::Timer::sleep(0.050f); }
+    ASSERT_TRUE( done );
+    th.join();
+}
+
+TEST_F(SoftcamStream, releaseFrameBuffer_must_not_lock_the_filter_state)
+{
+    auto fb = createFrameBufer(320, 240, 60);
+    SetUpSoftcamStream();
+
+    CAutoLock lock(m_softcam->pStateLock()); // 1st lock
+    std::atomic<int> done{false};
+    std::thread th([&]
+    {
+        // A deadlock occurs if this code attempts to get lock.
+        m_softcam->releaseFrameBuffer();
+        done = true;
+    });
+
+    for (int i = 0; !done && i < 20; i++) { sc::Timer::sleep(0.050f); }
+    ASSERT_TRUE( done );
+    th.join();
+}
+
 
 } //namespace