fix overscan issue and enable linkify of partial shown matches

src/Buffer.ts

@@ -371,8 +371,8 @@ export class Buffer implements IBuffer {
     this.markers.splice(this.markers.indexOf(marker), 1);
   }
 
-  public iterator(trimRight: boolean, startIndex?: number, endIndex?: number): IBufferStringIterator {
-    return new BufferStringIterator(this, trimRight, startIndex, endIndex);
+  public iterator(trimRight: boolean, startIndex?: number, endIndex?: number, startOverscan?: number, endOverscan?: number): IBufferStringIterator {
+    return new BufferStringIterator(this, trimRight, startIndex, endIndex, startOverscan, endOverscan);
   }
 }
 
@@ -401,6 +401,18 @@ export class Marker extends EventEmitter implements IMarker {
   }
 }
 
+/**
+ * Iterator to get unwrapped content strings from the buffer.
+ * The iterator returns at least the string data between the borders
+ * `startIndex` and `endIndex` (exclusive) and will expand the lines
+ * by `startOverscan` to the top and by `endOverscan` to the bottom,
+ * if no new line was found in between.
+ * It will never read/return string data beyond `startIndex - startOverscan`
+ * or `endIndex + endOverscan`. Therefore the first and last line might be truncated.
+ * It is possible to always get the full string for the first and last line as well
+ * by setting the overscan values to the actual buffer length, but not recommended
+ * since it might return the whole buffer within a single string in a worst case scenario.
+ */
 export class BufferStringIterator implements IBufferStringIterator {
   private _current: number;
 
@@ -408,7 +420,9 @@ export class BufferStringIterator implements IBufferStringIterator {
     private _buffer: IBuffer,
     private _trimRight: boolean,
     private _startIndex: number = 0,
-    private _endIndex: number = _buffer.lines.length
+    private _endIndex: number = _buffer.lines.length,
+    private _startOverscan: number = 0,
+    private _endOverscan: number = 0
   ) {
     this._current = this._startIndex;
   }
@@ -419,6 +433,12 @@ export class BufferStringIterator implements IBufferStringIterator {
 
   public next(): IBufferStringIteratorResult {
     const range = this._buffer.getWrappedRangeForLine(this._current);
+    if (range.first < this._startIndex - this._startOverscan) {
+      range.first = this._startIndex - this._startOverscan;
+    }
+    if (range.last > this._endIndex + this._endOverscan) {
+      range.last = this._endIndex + this._endOverscan;
+    }
     let result = '';
     for (let i = range.first; i <= range.last; ++i) {
       // TODO: always apply trimRight after fixing #1685

src/Linkifier.ts

@@ -21,6 +21,12 @@ export class Linkifier extends EventEmitter implements ILinkifier {
    */
   protected static readonly TIME_BEFORE_LINKIFY = 200;
 
+  /**
+   * Limit of the unwrapping line expansion (overscan) at the top and bottom
+   * of the actual viewport.
+   */
+  protected static readonly OVERSCAN_LIMIT = 5;
+
   protected _linkMatchers: ILinkMatcher[] = [];
 
   private _mouseZoneManager: IMouseZoneManager;
@@ -88,11 +94,17 @@ export class Linkifier extends EventEmitter implements ILinkifier {
       return;
     }
 
-    // iterate over the range of unwrapped content strings within start..end (excluding)
-    // _doLinkifyRow gets full unwrapped lines with the start row as buffer offset for every matcher
-    // for wrapped content over several rows the iterator might return rows outside the viewport
-    // we skip those later in _doLinkifyRow
-    const iterator = this._terminal.buffer.iterator(false, absoluteRowIndexStart, this._terminal.buffer.ydisp + this._rowsToLinkify.end + 1);
+    // Iterate over the range of unwrapped content strings within start..end (excluding).
+    // _doLinkifyRow gets full unwrapped lines with the start row as buffer offset for every matcher.
+    // The unwrapping is needed to also match content that got wrapped at the right side.
+    // To avoid a worst case szenario where the whole buffer contains just a single unwrapped string
+    // we limit this line expansion beyond the actual viewport to -5 and +5 real buffer lines (overscan).
+    // This comes with the tradeoff that match longer than 5 buffer lines will not match anymore at the
+    // viewport borders.
+    const iterator = this._terminal.buffer.iterator(
+      false, absoluteRowIndexStart, this._terminal.buffer.ydisp + this._rowsToLinkify.end + 1,
+      Linkifier.OVERSCAN_LIMIT, Linkifier.OVERSCAN_LIMIT);
+    console.log('linkify rows', absoluteRowIndexStart, this._terminal.buffer.ydisp + this._rowsToLinkify.end + 1);
     while (iterator.hasNext()) {
       const lineData: IBufferStringIteratorResult = iterator.next();
       for (let i = 0; i < this._linkMatchers.length; i++) {
@@ -204,14 +216,6 @@ export class Linkifier extends EventEmitter implements ILinkifier {
       // get the buffer index as [absolute row, col] for the match
       const bufferIndex = this._terminal.buffer.stringIndexToBufferIndex(rowIndex, stringIndex);
 
-      // skip rows outside of the viewport
-      if (bufferIndex[0] - this._terminal.buffer.ydisp < 0) {
-        continue;
-      }
-      if (bufferIndex[0] - this._terminal.buffer.ydisp > this._terminal.rows) {
-        break;
-      }
-
       const line = this._terminal.buffer.lines.get(bufferIndex[0]);
       const char = line.get(bufferIndex[1]);
       let fg: number | undefined;
@@ -254,6 +258,7 @@ export class Linkifier extends EventEmitter implements ILinkifier {
       x2 = this._terminal.cols;
       y2--;
     }
+    console.log(x1, y1, x2, y2);
 
     this._mouseZoneManager.add(new MouseZone(
       x1 + 1,

src/Types.ts

@@ -296,7 +296,7 @@ export interface IBuffer {
   nextStop(x?: number): number;
   prevStop(x?: number): number;
   stringIndexToBufferIndex(lineIndex: number, stringIndex: number): number[];
-  iterator(trimRight: boolean, startIndex?: number, endIndex?: number): IBufferStringIterator;
+  iterator(trimRight: boolean, startIndex?: number, endIndex?: number, startOverscan?: number, endOverscan?: number): IBufferStringIterator;
 }
 
 export interface IBufferSet extends IEventEmitter {