Rework file copy/open-read-write-close data handlingv0.6.83

Stick to the POSIX open(2), read(2), write(2), close(2) return values
semantics, apply on the VFS interface.

Also handle short reads and writes that are common for some gvfs
backends. This makes cross-VFS copy work.

1 files changed, 39 insertions, 32 deletions

diff --git a/UCoreWorkers.pas b/UCoreWorkers.pas
index 507e2b7..75a9453 100644
--- a/UCoreWorkers.pas
+++ b/UCoreWorkers.pas
@@ -1019,11 +1019,12 @@ var DefResponse: integer;   //  Global variables for this function
   var fsrc, fdst: TEngineFileDes;
       BSize: integer;
       Buffer: Pointer;
-      BytesDone, BytesRead, BytesWritten: Int64;
+      BytesDone, BytesRead, BytesWritten, BytesRemaining: Int64;
       LocalError: PGError;
   begin
     Result := False;
     LocalError := nil;
+    BytesDone := 0;
     DebugMsg(['ManualCopyFile: ', SourceFile, ' ---> ', DestFile]);
     fsrc := SrcEngine.OpenFile(SourceFile, omRead, @LocalError);
     if fsrc = nil then begin
@@ -1042,7 +1043,6 @@ var DefResponse: integer;   //  Global variables for this function
       Exit;
     end;
 
-    BytesDone := 0;
     BSize := DestEngine.GetBlockSize;
     Buffer := malloc(BSize);
     if Buffer = nil then begin
@@ -1050,60 +1050,66 @@ var DefResponse: integer;   //  Global variables for this function
       CopyFilesWorker_ProgressFunc(Self, 0, Error^);   //  Memory allocation failed
       Exit;
     end;
-    memset(Buffer, 0, BSize);
 
-    BytesWritten := 0;
     repeat
+      //  Read block
       BytesRead := SrcEngine.ReadFile(fsrc, Buffer, BSize, @LocalError);
-      if (BytesRead = 0) and (Error^ <> nil) then begin
+      if BytesRead < 0 then begin
         g_set_error(Error, TUXCMD_ERROR, gint(TUXCMD_ERROR_SOURCE_READ), LocalError^.message);
         g_error_free(LocalError);
         LocalError := nil;
-        Result := CopyFilesWorker_ProgressFunc(Self, BytesWritten, Error^);   //  Cannot read from source file
+        Result := CopyFilesWorker_ProgressFunc(Self, BytesDone, Error^);   //  Cannot read from source file
         if Result then begin
           g_error_free(Error^);
           Error^ := nil;
           Continue;
         end else Break;
       end;
+
+      //  Write block
       if BytesRead > 0 then begin
-        BytesWritten := DestEngine.WriteFile(fdst, Buffer, BytesRead, @LocalError);
-        if (BytesWritten < BytesRead) then begin
+        BytesRemaining := BytesRead;
+        repeat
+          BytesWritten := DestEngine.WriteFile(fdst, Buffer + (BytesRead - BytesRemaining), BytesRemaining, @LocalError);
+          if BytesWritten > 0 then
+            BytesRemaining := BytesRemaining - BytesWritten;
+        until (BytesRemaining = 0) or (BytesWritten <= 0);
+        if BytesWritten < 0 then begin
           g_set_error(Error, TUXCMD_ERROR, gint(TUXCMD_ERROR_TARGET_WRITE), LocalError^.message);
           g_error_free(LocalError);
           LocalError := nil;
-          Result := CopyFilesWorker_ProgressFunc(Self, BytesWritten, Error^);   //  Cannot write to target file
-          if Result then begin
-            g_error_free(Error^);
-            Error^ := nil;
-            Continue;
-          end else Break;
+          Result := False;
+          CopyFilesWorker_ProgressFunc(Self, BytesDone, Error^);   //  Cannot write to target file
+          Break;
         end;
       end;
+      // BytesRead == 0 means EOF
       BytesDone := BytesDone + BytesRead;
       Result := CopyFilesWorker_ProgressFunc(Self, BytesDone, nil);
       if not Result then Break;
-    until (BytesRead = 0) or (BytesWritten < BytesRead);
+    until BytesRead <= 0;
     libc_free(Buffer);
 
-    if not DestEngine.CloseFile(fdst, @LocalError) then begin
-      g_set_error(Error, TUXCMD_ERROR, gint(TUXCMD_ERROR_TARGET_CLOSE), LocalError^.message);
-      g_error_free(LocalError);
-      Result := False;
-      SrcEngine.CloseFile(fsrc, nil);
-      CopyFilesWorker_ProgressFunc(Self, BytesDone, Error^);   //  Cannot close target file
-      Exit;
-    end;
-    if not SrcEngine.CloseFile(fsrc, @LocalError) then begin
-      g_set_error(Error, TUXCMD_ERROR, gint(TUXCMD_ERROR_SOURCE_CLOSE), LocalError^.message);
-      g_error_free(LocalError);
-      Result := CopyFilesWorker_ProgressFunc(Self, BytesDone, Error^);   //  Cannot close source file
+    if not DestEngine.CloseFile(fdst, @LocalError) then
       if Result then begin
-        //  user has chosen to ignore the error
-        g_error_free(Error^);
-        Error^ := nil;
-      end else Exit;
-    end;
+        g_set_error(Error, TUXCMD_ERROR, gint(TUXCMD_ERROR_TARGET_CLOSE), LocalError^.message);
+        g_error_free(LocalError);
+        Result := False;
+        SrcEngine.CloseFile(fsrc, nil);
+        CopyFilesWorker_ProgressFunc(Self, BytesDone, Error^);   //  Cannot close target file
+        Exit;
+      end;
+    if not SrcEngine.CloseFile(fsrc, @LocalError) then
+      if Result then begin
+        g_set_error(Error, TUXCMD_ERROR, gint(TUXCMD_ERROR_SOURCE_CLOSE), LocalError^.message);
+        g_error_free(LocalError);
+        Result := CopyFilesWorker_ProgressFunc(Self, BytesDone, Error^);   //  Cannot close source file
+        if Result then begin
+          //  user has chosen to ignore the error
+          g_error_free(Error^);
+          Error^ := nil;
+        end else Exit;
+      end;
   end;
 
   //  Returns True if the file was successfully copied and will be deleted on move
@@ -1120,6 +1126,7 @@ var DefResponse: integer;   //  Global variables for this function
         then Result := DestEngine.CopyFileIn(SourceFile, DestFile, Append, @CopyFilesWorker_ProgressFunc, Self, Error)
       else
 
+      //  TODO: check for reported Append capability and fall back to manual copy if needed
       //  from local engine to VFS engine
       if (SrcEngine is TLocalTreeEngine) and (DestEngine is TVFSEngine) then
       begin