/// <inheritdoc />
public Task <GetContentHashListResult> GetContentHashListAsync(Context context, StrongFingerprint strongFingerprint, CancellationToken cts, UrgencyHint urgencyHint)
{
return(WithOperationContext(
context,
cts,
operationContext => operationContext.PerformOperationAsync(
DistributedTracer,
operation: async() =>
{
GetContentHashListResult innerResult = null;
// Get the value from the metadata cache or load the current inner value into it (and then return it)
var existing = await MetadataCache.GetOrAddContentHashListAsync(
context,
strongFingerprint,
async fingerprint =>
{
innerResult = await _innerCacheSession.GetContentHashListAsync(context, fingerprint, cts, urgencyHint);
return innerResult;
});
// Check to see if we need to need to read through to the inner value.
if (_readThroughMode == ReadThroughMode.ReadThrough &&
existing.Succeeded &&
!(existing.ContentHashListWithDeterminism.Determinism.IsDeterministic &&
existing.ContentHashListWithDeterminism.Determinism.Guid == _innerCacheId))
{
// Read through to the inner cache because the metadata cache's value is not guaranteed to be backed.
if (innerResult == null)
{
// We did not already query the inner cache as part of the original query, so do that now.
innerResult = await _innerCacheSession.GetContentHashListAsync(
context,
strongFingerprint,
cts,
urgencyHint);
}
if (innerResult != null && innerResult.Succeeded &&
innerResult.ContentHashListWithDeterminism.Determinism.IsDeterministic)
{
// If the inner cache's value is now backed, clear the value from the metadata cache so that the
// next read will load the backed value into the metadata cache (preventing the need for future read-throughs).
await MetadataCache.DeleteFingerprintAsync(context, strongFingerprint).IgnoreFailure();
}
return innerResult;
}
else
{
// Return the existing value in the metadata cache, or any error.
return existing;
}
},
traceOperationStarted: true,
extraStartMessage: $"StrongFingerprint=({strongFingerprint})",
extraEndMessage: result => $"StrongFingerprint=({strongFingerprint}) {result.ContentHashListWithDeterminism.ToTraceString()}")));
}
/// <inheritdoc />
public async Task <Possible <CasEntries, Failure> > GetCacheEntryAsync(StrongFingerprint strong, UrgencyHint urgencyHint, Guid activityId)
{
var hashListResult = await ReadOnlyCacheSession.GetContentHashListAsync(
new Context(Logger),
new BuildXL.Cache.MemoizationStore.Interfaces.Sessions.StrongFingerprint(
strong.WeakFingerprint.ToMemoization(),
new Selector(strong.CasElement.ToMemoization(), strong.HashElement.RawHash.ToByteArray())),
CancellationToken.None);
if (hashListResult.Succeeded)
{
if (hashListResult.ContentHashListWithDeterminism.ContentHashList == null)
{
return(new NoMatchingFingerprintFailure(strong));
}
SessionEntries?.TryAdd(strong, 1);
return(hashListResult.ContentHashListWithDeterminism.FromMemoization());
}
else
{
return(new CacheFailure(hashListResult.ErrorMessage));
}
}