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Disposing SKStreamAsset when asset MemoryBase is not IntPtr.Zero #3376

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Disposing SKStreamAsset when asset MemoryBase is not IntPtr.Zero #3376

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2 changes: 1 addition & 1 deletion source/SkiaSharp.HarfBuzz/SkiaSharp.HarfBuzz/BlobExtensions.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -27,7 +27,7 @@ public static Blob ToHarfBuzzBlob(this SKStreamAsset asset)
{
var ptr = Marshal.AllocCoTaskMem(size);
asset.Read(ptr, size);
blob = new Blob(ptr, size, MemoryMode.ReadOnly, () => Marshal.FreeCoTaskMem(ptr));
blob = new Blob(ptr, size, MemoryMode.ReadOnly, () => { Marshal.FreeCoTaskMem(ptr); asset.Dispose(); });
Comment on lines 28 to +30
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Copilot AI Jan 26, 2026

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asset.Read(ptr, size) can return fewer bytes than requested; the return value is ignored and the blob is created with length = size anyway. This can lead to HarfBuzz reading uninitialized memory and producing incorrect shaping results. Consider reading in a loop until size bytes are read (or throw if EOF/0 bytes read early), and create the Blob with the actual number of bytes read.

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Copilot AI Jan 26, 2026

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This change fixes a resource-leak scenario; please add a unit test that asserts the SKStreamAsset is disposed when the returned Blob is disposed for both paths: (1) a stream with GetMemoryBase() != IntPtr.Zero (e.g., SKMemoryStream) and (2) a stream with GetMemoryBase() == IntPtr.Zero (e.g., SKFileStream).

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Copilot AI Jan 26, 2026

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The PR title/description mention the leak when MemoryBase is not IntPtr.Zero, but this change disposes the asset in the memoryBase == IntPtr.Zero branch. Please update the PR title/description (or clarify the scenario) to match what is being fixed.

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}

blob.MakeImmutable();
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