Eliminate redundant dictionary lookups

Author: iamcarbon

Src/Fido2.AspNet/DistributedCacheMetadataService.cs

@@ -44,13 +44,11 @@ public virtual MetadataBLOBPayloadEntry GetEntry(Guid aaguid)
             if (!IsInitialized())
                 throw new InvalidOperationException("MetadataService must be initialized");
 
-            if (_entries.ContainsKey(aaguid))
+            if (_entries.TryGetValue(aaguid, out MetadataBLOBPayloadEntry entry))
             {
-                var entry = _entries[aaguid];
-
-                if (_metadataStatements.ContainsKey(aaguid))
+                if (_metadataStatements.TryGetValue(aaguid, out var statement))
                 {
-                    entry.MetadataStatement = _metadataStatements[aaguid];
+                    entry.MetadataStatement = statement;
                 }
 
                 return entry;

Src/Fido2/AttestationFormat/Tpm.cs

@@ -479,9 +479,9 @@ public static (ushort size, byte[] name) NameFromTPM2BName(ReadOnlySpan<byte> ab
             if (Enum.IsDefined(typeof(TpmAlg), size))
             {
                 var tpmalg = (TpmAlg)size;
-                if (tpmAlgToDigestSizeMap.ContainsKey(tpmalg))
+                if (tpmAlgToDigestSizeMap.TryGetValue(tpmalg, out ushort tplAlgDigestSize))
                 {
-                    name = AuthDataHelper.GetSizedByteArray(ab, ref offset, tpmAlgToDigestSizeMap[tpmalg]);
+                    name = AuthDataHelper.GetSizedByteArray(ab, ref offset, tplAlgDigestSize);
                 }
                 else
                 {

Src/Fido2/SimpleMetadataService.cs

@@ -32,9 +32,9 @@ public bool ConformanceTesting()
 
             if (_entries.TryGetValue(aaguid, out MetadataBLOBPayloadEntry? entry))
             {
-                if (_metadataStatements.ContainsKey(aaguid))
+                if (_metadataStatements.TryGetValue(aaguid, out var metadataStatement))
                 {
-                    entry.MetadataStatement = _metadataStatements[aaguid];
+                    entry.MetadataStatement = metadataStatement;
                 }
 
                 return entry;