Fix Deep Scanline Input crash when using a framebuffer as parameter (AcademySoftwareFoundation#2019)

* Fix Deep Scanline Input crash when using an externally allocated framebuffer

The Deep Scanline Input code has recently been rewritten to make use of the
EXR core library. As a result a bug was introduced when using the overloads of
readPixels() and readPixelSampleCounts() that use externally provided
framebuffers as parameters, a hard crash was occuring. According to the comment
on the header of these functions, when these overloads are used the InputFile's
frameBuffer is not used.
However both these functions call into readMemData(), which does use the
InputFile's member framebuffer, which has not been allocated, resulting into a
segmentation fault.
This commit fixes the above issue, by using the parameter framebuffer that is
passed in, which should be allocated by the caller application.

Signed-off-by: Nikolaos Koutsikos <nikolaos.koutsikos@foundry.com>

* Add a Deep Scanline Input test that uses a framebuffer parameter

After having found a bug with the readPixels() and readPixelSampleCounts()
overloads that receive a framebuffer parameter, it was made apparent that there
was a hole in our tests to cover these functions.
This commits slightly refactors the DeepScanLineBasic tests and adds a third
read path to add coverage for this case as well.

Signed-off-by: Nikolaos Koutsikos <nikolaos.koutsikos@foundry.com>

---------

Signed-off-by: Nikolaos Koutsikos <nikolaos.koutsikos@foundry.com>

Author: nikos-foundry

src/lib/OpenEXR/ImfDeepScanLineInputFile.cpp

@@ -629,7 +629,7 @@ DeepScanLineInputFile::Data::readMemData (
         *_ctxt,
         partNumber,
         rawPixelData,
-        &frameBuffer,
+        &fb,
         scanLine1,
         scanLine2,
         fills);

src/test/OpenEXRTest/testDeepScanLineBasic.cpp

@@ -243,11 +243,18 @@ generateRandomFile (
             }
 }
 
+enum ReadType
+{
+    eReadBulk = 1,
+    eReadScanline,
+    eReadScanlinelFrameBuffer
+};
+
 void
 readFile (
     const std::string& filename,
     int                channelCount,
-    bool               bulkRead,
+    ReadType           readType,
     bool               randomChannels)
 {
     if (randomChannels) { cout << " reading random channels " << flush; }
@@ -352,9 +359,12 @@ readFile (
                 pointerSize * width,                // yStride// 10
                 sampleSize));                       // sampleStride
     }
-    file.setFrameBuffer (frameBuffer);
+    if (readType != eReadScanlinelFrameBuffer)
+    {
+        file.setFrameBuffer (frameBuffer);
+    }
 
-    if (bulkRead)
+    if (readType == eReadBulk)
     {
         cout << "bulk " << flush;
         file.readPixelSampleCounts (dataWindow.min.y, dataWindow.max.y);
@@ -397,10 +407,24 @@ readFile (
     else
     {
         cout << "per-line " << flush;
+        if (readType == eReadScanlinelFrameBuffer) cout << "framebuffer " << flush;
         for (int i = 0; i < dataWindow.max.y - dataWindow.min.y + 1; i++)
         {
             int y = i + dataWindow.min.y;
-            file.readPixelSampleCounts (y);
+            vector<char> buffer;
+            if (readType == eReadScanlinelFrameBuffer)
+            {
+                uint64_t pixSize = 0;
+                file.rawPixelData (y, nullptr, pixSize);
+                buffer.resize (pixSize);
+                file.rawPixelData (y, buffer.data(), pixSize);
+                file.readPixelSampleCounts (buffer.data(), frameBuffer, y, y);
+            }
+            else // readType == eReadScanline
+            {
+                file.readPixelSampleCounts (y);
+            }
+
 
             for (int j = 0; j < width; j++)
                 assert (localSampleCount[i][j] == sampleCount[i][j]);
@@ -431,7 +455,14 @@ readFile (
                 }
             }
 
-            file.readPixels (y);
+            if (readType == eReadScanlinelFrameBuffer)
+            {
+                file.readPixels (buffer.data(), frameBuffer, y, y);
+            }
+            else // readType == eReadScanline
+            {
+                file.readPixels (y);
+            }
         }
     }
 
@@ -539,8 +570,10 @@ readWriteTest (
             false,
             dataWindow,
             displayWindow);
-        readFile (filename, channelCount, false, false);
-        if (channelCount > 1) readFile (filename, channelCount, false, true);
+        readFile (filename, channelCount, eReadScanline, false);
+        if (channelCount > 1) readFile (filename, channelCount, eReadScanline, true);
+        readFile (filename, channelCount, eReadScanlinelFrameBuffer, false);
+        if (channelCount > 1) readFile (filename, channelCount, eReadScanlinelFrameBuffer, true);
         remove (filename.c_str ());
         cout << endl << flush;
 
@@ -551,8 +584,8 @@ readWriteTest (
             true,
             dataWindow,
             displayWindow);
-        readFile (filename, channelCount, true, false);
-        if (channelCount > 1) readFile (filename, channelCount, true, true);
+        readFile (filename, channelCount, eReadBulk, false);
+        if (channelCount > 1) readFile (filename, channelCount, eReadBulk, true);
         remove (filename.c_str ());
         cout << endl << flush;
     }