Add 'file already downloaded' support to download with issigverify as well.

Projects/Src/Setup.InstFunc.pas

@@ -12,7 +12,7 @@ unit Setup.InstFunc;
 interface
 
 uses
-  Windows, SysUtils, Shared.Int64Em, SHA256, Shared.CommonFunc;
+  Windows, SysUtils, Shared.Int64Em, SHA256, Shared.CommonFunc, Shared.FileClass;
 
 type
   PSimpleStringListArray = ^TSimpleStringListArray;
@@ -58,7 +58,8 @@ function GenerateNonRandomUniqueTempDir(const LimitCurrentUserSidAccess: Boolean
 function GetComputerNameString: String;
 function GetFileDateTime(const DisableFsRedir: Boolean; const Filename: String;
   var DateTime: TFileTime): Boolean;
-function GetSHA256OfFile(const DisableFsRedir: Boolean; const Filename: String): TSHA256Digest;
+function GetSHA256OfFile(const DisableFsRedir: Boolean; const Filename: String): TSHA256Digest; overload;
+function GetSHA256OfFile(const F: TFile): TSHA256Digest; overload;
 function GetSHA256OfAnsiString(const S: AnsiString): TSHA256Digest;
 function GetSHA256OfUnicodeString(const S: UnicodeString): TSHA256Digest;
 function GetRegRootKeyName(const RootKey: HKEY): String;
@@ -99,7 +100,7 @@ implementation
 
 uses
   Messages, ShellApi, PathFunc, SetupLdrAndSetup.InstFunc, SetupLdrAndSetup.Messages,
-  Shared.SetupMessageIDs, Shared.FileClass, SetupLdrAndSetup.RedirFunc, Shared.SetupTypes,
+  Shared.SetupMessageIDs, SetupLdrAndSetup.RedirFunc, Shared.SetupTypes,
   Classes, RegStr, Math;
 
 procedure InternalError(const Id: String);
@@ -553,21 +554,28 @@ end;
 function GetSHA256OfFile(const DisableFsRedir: Boolean; const Filename: String): TSHA256Digest;
 { Gets SHA-256 sum as a string of the file Filename. An exception will be raised upon
   failure. }
+begin
+  const F = TFileRedir.Create(DisableFsRedir, Filename, fdOpenExisting, faRead, fsReadWrite);
+  try
+    Result := GetSHA256OfFile(F);
+  finally
+    F.Free;
+  end;
+end;
+
+function GetSHA256OfFile(const F: TFile): TSHA256Digest;
+{ Gets SHA-256 sum as a string of the file F. An exception will be raised upon
+  failure. }
 var
   Buf: array[0..65535] of Byte;
 begin
   var Context: TSHA256Context;
   SHA256Init(Context);
-  var F := TFileRedir.Create(DisableFsRedir, Filename, fdOpenExisting, faRead, fsReadWrite);
-  try
-    while True do begin
-      var NumRead := F.Read(Buf, SizeOf(Buf));
-      if NumRead = 0 then
-        Break;
-      SHA256Update(Context, Buf, NumRead);
-    end;
-  finally
-    F.Free;
+  while True do begin
+    var NumRead := F.Read(Buf, SizeOf(Buf));
+    if NumRead = 0 then
+      Break;
+    SHA256Update(Context, Buf, NumRead);
   end;
   Result := SHA256Final(Context);
 end;

Projects/Src/Setup.Install.pas

@@ -1968,7 +1968,7 @@ var
               DoISSigVerify(ISSigVerifySourceF, nil, ArchiveFilename, CurFile^.ISSigAllowedKeys,
                 ExpectedFileHash);
               { Can't get the SHA-256 while extracting so need to get and check it now }
-              const ActualFileHash = GetSHA256OfFile(DisableFsRedir, ArchiveFilename);
+              const ActualFileHash = GetSHA256OfFile(ISSigVerifySourceF);
               if not SHA256DigestsEqual(ActualFileHash, ExpectedFileHash) then
                 ISSigVerifyError(vseFileHashIncorrect, SetupMessages[msgSourceIsCorrupted]);
               Log(ISSigVerificationSuccessfulLogMessage);
@@ -3722,9 +3722,26 @@ begin
   const DisableFsRedir = False; { Like everything else working on the temp dir }
 
   { Prepare directory }
-  if FileExists(DestFile) then begin
-    if (RequiredSHA256OfFile <> '') and
-       (RequiredSHA256OfFile = SHA256DigestToString(GetSHA256OfFile(DisableFsRedir, DestFile))) then begin
+  if NewFileExists(DestFile) then begin
+    if ISSigVerify then begin
+      var ExistingFileSize: Int64;
+      var ExistingFileHash: TSHA256Digest;
+      if ISSigVerifySignature(DestFile, GetISSigAllowedKeys(ISSigAvailableKeys, ISSigAllowedKeys),
+           ExistingFileSize, ExistingFileHash, nil, nil, nil) then begin
+        const DestF = TFileRedir.Create(DisableFsRedir, DestFile, fdOpenExisting, faRead, fsReadWrite);
+        try
+          if (Int64(DestF.Size) = ExistingFileSize) and
+             (SHA256DigestsEqual(GetSHA256OfFile(DestF), ExistingFileHash)) then begin
+            Log('  File already downloaded.');
+            Result := 0;
+            Exit;
+          end;
+        finally
+          DestF.Free;
+        end;
+      end;
+    end else if (RequiredSHA256OfFile <> '') and
+                SameText(RequiredSHA256OfFile, SHA256DigestToString(GetSHA256OfFile(DisableFsRedir, DestFile))) then begin
       Log('  File already downloaded.');
       Result := 0;
       Exit;