Use hashes for language service cache keys (dotnet#6058)

* Use hashes for language service cache keys * Fix dumb thing I forgot * I guess this is required ayyy lmao * Override HashCode instead and do a few less computations * Remove ToString in obj expression
xamarin · Jan 14, 2019 · 39dca03 · 39dca03
1 parent 7280506
commit 39dca03
Showing 1 changed file with 59 additions and 38 deletions.
diff --git a/Common/Extensions.fs b/Common/Extensions.fs
@@ -46,61 +46,82 @@ module private SourceText =
 
     open System.Runtime.CompilerServices
 
+    /// Ported from Roslyn.Utilities
+    [<RequireQualifiedAccess>]
+    module Hash =
+        /// (From Roslyn) This is how VB Anonymous Types combine hash values for fields.
+        let combine (newKey: int) (currentKey: int) = (currentKey * (int 0xA5555529)) + newKey
+
+        let combineValues (values: seq<'T>) =
+            (0, values) ||> Seq.fold (fun hash value -> combine (value.GetHashCode()) hash)
+
     let weakTable = ConditionalWeakTable<SourceText, ISourceText>()
 
     let create (sourceText: SourceText) =
         let sourceText =
-            { new ISourceText with
+            { 
+                new Object() with
+                    override __.GetHashCode() =
+                        let checksum = sourceText.GetChecksum()
+                        let contentsHash = if not checksum.IsDefault then Hash.combineValues checksum else 0
+                        let encodingHash = if not (isNull sourceText.Encoding) then sourceText.Encoding.GetHashCode() else 0
+
+                        sourceText.ChecksumAlgorithm.GetHashCode()
+                        |> Hash.combine encodingHash
+                        |> Hash.combine contentsHash
+                        |> Hash.combine sourceText.Length
+
+                interface ISourceText with
 
-                member __.Item with get index = sourceText.[index]
+                    member __.Item with get index = sourceText.[index]
 
-                member __.GetLineString(lineIndex) =
-                    sourceText.Lines.[lineIndex].ToString()
+                    member __.GetLineString(lineIndex) =
+                        sourceText.Lines.[lineIndex].ToString()
 
-                member __.GetLineCount() =
-                    sourceText.Lines.Count
+                    member __.GetLineCount() =
+                        sourceText.Lines.Count
 
-                member __.GetLastCharacterPosition() =
-                    if sourceText.Lines.Count > 0 then
-                        (sourceText.Lines.Count, sourceText.Lines.[sourceText.Lines.Count - 1].Span.Length)
-                    else
-                        (0, 0)
+                    member __.GetLastCharacterPosition() =
+                        if sourceText.Lines.Count > 0 then
+                            (sourceText.Lines.Count, sourceText.Lines.[sourceText.Lines.Count - 1].Span.Length)
+                        else
+                            (0, 0)
 
-                member __.GetSubTextString(start, length) =
-                    sourceText.GetSubText(TextSpan(start, length)).ToString()
+                    member __.GetSubTextString(start, length) =
+                        sourceText.GetSubText(TextSpan(start, length)).ToString()
 
-                member __.SubTextEquals(target, startIndex) =
-                    if startIndex < 0 || startIndex >= sourceText.Length then
-                        invalidArg "startIndex" "Out of range."
+                    member __.SubTextEquals(target, startIndex) =
+                        if startIndex < 0 || startIndex >= sourceText.Length then
+                            invalidArg "startIndex" "Out of range."
 
-                    if String.IsNullOrEmpty(target) then
-                        invalidArg "target" "Is null or empty."
+                        if String.IsNullOrEmpty(target) then
+                            invalidArg "target" "Is null or empty."
 
-                    let lastIndex = startIndex + target.Length
-                    if lastIndex <= startIndex || lastIndex >= sourceText.Length then
-                        invalidArg "target" "Too big."
+                        let lastIndex = startIndex + target.Length
+                        if lastIndex <= startIndex || lastIndex >= sourceText.Length then
+                            invalidArg "target" "Too big."
 
-                    let mutable finished = false
-                    let mutable didEqual = true
-                    let mutable i = 0
-                    while not finished && i < target.Length do
-                        if target.[i] <> sourceText.[startIndex + i] then
-                            didEqual <- false
-                            finished <- true // bail out early                        
-                        else
-                            i <- i + 1
+                        let mutable finished = false
+                        let mutable didEqual = true
+                        let mutable i = 0
+                        while not finished && i < target.Length do
+                            if target.[i] <> sourceText.[startIndex + i] then
+                                didEqual <- false
+                                finished <- true // bail out early                        
+                            else
+                                i <- i + 1
 
-                    didEqual
+                        didEqual
 
-                member __.ContentEquals(sourceText) =
-                    match sourceText with
-                    | :? SourceText as sourceText -> sourceText.ContentEquals(sourceText)
-                    | _ -> false
+                    member __.ContentEquals(sourceText) =
+                        match sourceText with
+                        | :? SourceText as sourceText -> sourceText.ContentEquals(sourceText)
+                        | _ -> false
 
-                member __.Length = sourceText.Length
+                    member __.Length = sourceText.Length
 
-                member __.CopyTo(sourceIndex, destination, destinationIndex, count) =
-                    sourceText.CopyTo(sourceIndex, destination, destinationIndex, count)
+                    member __.CopyTo(sourceIndex, destination, destinationIndex, count) =
+                        sourceText.CopyTo(sourceIndex, destination, destinationIndex, count)
             }
 
         sourceText