private static int MarshalPdbReader(IDebugUpdateInMemoryPE2 updater, out IntPtr pdbReaderPointer)
{
// ISymUnmanagedReader can only be accessed from an MTA thread, however, we need
// fetch the IUnknown instance (call IENCSymbolReaderProvider.GetSymbolReader) here
// in the STA. To further complicate things, we need to return synchronously from
// this method. Waiting for the MTA thread to complete so we can return synchronously
// blocks the STA thread, so we need to make sure the CLR doesn't try to marshal
// ISymUnmanagedReader calls made in an MTA back to the STA for execution (if this
// happens we'll be deadlocked). We'll use CoMarshalInterThreadInterfaceInStream to
// achieve this. First, we'll marshal the object in a Stream and pass a Stream pointer
// over to the MTA. In the MTA, we'll get the Stream from the pointer and unmarshal
// the object. The reader object was originally created on an MTA thread, and the
// instance we retrieved in the STA was a proxy. When we unmarshal the Stream in the
// MTA, it "unwraps" the proxy, allowing us to directly call the implementation.
// Another way to achieve this would be for the symbol reader to implement IAgileObject,
// but the symbol reader we use today does not. If that changes, we should consider
// removing this marshal/unmarshal code.
IENCDebugInfo debugInfo;
updater.GetENCDebugInfo(out debugInfo);
var symbolReaderProvider = (IENCSymbolReaderProvider)debugInfo;
object pdbReaderObjSta;
symbolReaderProvider.GetSymbolReader(out pdbReaderObjSta);
int hr = NativeMethods.GetStreamForObject(pdbReaderObjSta, out pdbReaderPointer);
Marshal.ReleaseComObject(pdbReaderObjSta);
return hr;
}
private unsafe void SetFileUpdates(
IDebugUpdateInMemoryPE2 updater,
List<KeyValuePair<DocumentId, ImmutableArray<LineChange>>> edits)
{
int totalEditCount = edits.Sum(e => e.Value.Length);
if (totalEditCount == 0)
{
return;
}
var lineUpdates = new LINEUPDATE[totalEditCount];
fixed (LINEUPDATE* lineUpdatesPtr = lineUpdates)
{
int index = 0;
var fileUpdates = new FILEUPDATE[edits.Count];
for (int f = 0; f < fileUpdates.Length; f++)
{
var documentId = edits[f].Key;
var deltas = edits[f].Value;
fileUpdates[f].FileName = _vsProject.GetDocumentOrAdditionalDocument(documentId).FilePath;
fileUpdates[f].LineUpdateCount = (uint)deltas.Length;
fileUpdates[f].LineUpdates = (IntPtr)(lineUpdatesPtr + index);
for (int l = 0; l < deltas.Length; l++)
{
lineUpdates[index + l].Line = (uint)deltas[l].OldLine;
lineUpdates[index + l].UpdatedLine = (uint)deltas[l].NewLine;
}
index += deltas.Length;
}
// The updater makes a copy of all data, we can release the buffer after the call.
updater.SetFileUpdates(fileUpdates, (uint)fileUpdates.Length);
}
}
