Merge 7cc63e3005 into 54d6654ad1

src/fviewer.pas

@@ -3043,6 +3043,36 @@ begin
   end;
 end;
 
+// Returns True if the file has lines longer than MaxLen bytes.
+// Only reads the first MaxLen+1 bytes to check.
+function FileHasLongLines(const sFileName: String; MaxLen: SizeInt): Boolean;
+var
+  CheckLen, J: SizeInt;
+  CheckBuf: AnsiString;
+begin
+  Result := False;
+  try
+    with TFileStreamUAC.Create(sFileName, fmOpenRead or fmShareDenyNone) do
+    try
+      CheckLen := Min(Size, MaxLen + 1);
+      SetLength(CheckBuf, CheckLen);
+      Read(Pointer(CheckBuf)^, CheckLen);
+      if CheckLen <= MaxLen then
+        Exit; // File is smaller than the limit
+      for J := 1 to CheckLen do
+      begin
+        if CheckBuf[J] in [#10, #13] then
+          Exit; // Found a newline within the limit
+      end;
+      Result := True; // No newline found in first MaxLen+1 bytes
+    finally
+      Free;
+    end;
+  except
+    Result := True; // On error, assume long lines to be safe
+  end;
+end;
+
 function TfrmViewer.CheckSynEdit(const sFileName: String; bForce: Boolean = False): Boolean;
 var
   AFile: TFile;
@@ -3094,6 +3124,19 @@ begin
       PushPop(FElevate);
     end;
   end;
+
+  // Skip files with extremely long lines (e.g. minified JSON)
+  // that would freeze SynEdit's highlighter/word-wrap.
+  if Result and not bForce then
+  begin
+    PushPop(FElevate);
+    try
+      if FileHasLongLines(sFileName, 8192) then
+        Result := False;
+    finally
+      PushPop(FElevate);
+    end;
+  end;
 end;
 
 function TfrmViewer.LoadGraphics(const sFileName:String): Boolean;

src/uthumbnails.pas

@@ -51,7 +51,7 @@ type
 implementation
 
 uses
-  StreamEx, URIParser, MD5, FileUtil, LazFileUtils, Forms, uDCUtils, DCOSUtils, DCStrUtils,
+  StreamEx, URIParser, MD5, FileUtil, LazFileUtils, Forms, Math, uDCUtils, DCOSUtils, DCStrUtils,
   uDebug, uReSample, uGlobsPaths, uGlobs, uPixmapManager, uFileSystemFileSource,
   uGraphics, uFileProcs;
 
@@ -92,9 +92,10 @@ end;
 procedure TThumbnailManager.DoCreatePreviewText;
 var
   S: String;
-  Y: Integer;
+  Y, P, LineStart: Integer;
   Stream: TFileStreamEx;
-  Reader: TStreamReader;
+  MaxChars, MaxRead: Integer;
+  Buf: AnsiString;
 begin
   FBitmap:= TBitmap.Create;
   with FBitmap do
@@ -104,18 +105,40 @@ begin
     Canvas.FillRect(Canvas.ClipRect);
     Canvas.Font.Color:= clWindowText;
     Canvas.Font.Size := FThumbBitmapSize.cy div 16;
+    // Estimate max visible characters per line from thumbnail width
+    MaxChars := FThumbBitmapSize.cx div Max(Canvas.TextWidth('M') div 2, 1);
+    MaxRead := 8192;
     try
       Stream:= TFileStreamEx.Create(FFileName, fmOpenRead or fmShareDenyNone);
       try
-        Y:= 0;
-        Reader:= TStreamReader.Create(Stream, BUFFER_SIZE, True);
-        repeat
-          S:= Reader.ReadLine;
+        if Stream.Size < MaxRead then MaxRead := Stream.Size;
+        SetLength(Buf, MaxRead);
+        Stream.Read(Pointer(Buf)^, MaxRead);
+      finally
+        Stream.Free;
+      end;
+      Y:= 0;
+      LineStart := 1;
+      P := 1;
+      while (Y < FThumbBitmapSize.cy) and (P <= Length(Buf)) do
+      begin
+        if Buf[P] in [#10, #13] then
+        begin
+          S := Copy(Buf, LineStart, Min(P - LineStart, MaxChars));
           Canvas.TextOut(0, Y, S);
           Y += Canvas.TextHeight(S) + 2;
-        until (Y >= FThumbBitmapSize.cy) or Reader.Eof;
-      finally
-        Reader.Free;
+          // Skip CR+LF pair
+          if (P < Length(Buf)) and (Buf[P] = #13) and (Buf[P + 1] = #10) then
+            Inc(P);
+          LineStart := P + 1;
+        end;
+        Inc(P);
+      end;
+      // Handle last line (or single-line file)
+      if (Y < FThumbBitmapSize.cy) and (LineStart <= Length(Buf)) then
+      begin
+        S := Copy(Buf, LineStart, Min(Length(Buf) - LineStart + 1, MaxChars));
+        Canvas.TextOut(0, Y, S);
       end;
     except
       // Ignore