fix possible key duplication in ReferencesHandler (yWorks#188)

fix yWorks#166

src/context/referenceshandler.ts

@@ -5,18 +5,21 @@ import { RGBColor } from '../utils/rgbcolor'
 export class ReferencesHandler {
   private readonly renderedElements: { [key: string]: SvgNode }
   private readonly idMap: { [id: string]: SvgNode }
+  private readonly idPrefix: string
+  private static instanceCounter = 0
 
   constructor(idMap: { [id: string]: SvgNode }) {
     this.renderedElements = {}
     this.idMap = idMap
+    this.idPrefix = String(ReferencesHandler.instanceCounter++)
   }
 
   public async getRendered(
     id: string,
     color: RGBColor | null,
     renderCallback: (node: SvgNode) => Promise<void>
   ): Promise<SvgNode> {
-    const key = ReferencesHandler.generateKey(id, color)
+    const key = this.generateKey(id, color)
     if (this.renderedElements.hasOwnProperty(key)) {
       return this.renderedElements[id]
     }
@@ -33,7 +36,7 @@ export class ReferencesHandler {
     return this.idMap[cssEsc(id, { isIdentifier: true })]
   }
 
-  public static generateKey(id: string, color: RGBColor | null): string {
-    return id + '|' + (color || new RGBColor('rgb(0,0,0)')).toRGBA()
+  public generateKey(id: string, color: RGBColor | null): string {
+    return this.idPrefix + '|' + id + '|' + (color || new RGBColor('rgb(0,0,0)')).toRGBA()
   }
 }

src/nodes/use.ts

@@ -9,7 +9,6 @@ import { SvgNode } from './svgnode'
 import { Symbol } from './symbol'
 import { Viewport } from '../context/viewport'
 import { RGBColor } from '../utils/rgbcolor'
-import { ReferencesHandler } from '../context/referenceshandler'
 
 /**
  * Draws the element referenced by a use node, makes use of pdf's XObjects/FormObjects so nodes are only written once
@@ -86,7 +85,7 @@ export class Use extends GraphicsNode {
       context.pdf.clip().discardPath()
     }
 
-    context.pdf.doFormObject(ReferencesHandler.generateKey(id, color), t)
+    context.pdf.doFormObject(context.refsHandler.generateKey(id, color), t)
     context.pdf.restoreGraphicsState()
   }
 
@@ -112,7 +111,7 @@ export class Use extends GraphicsNode {
     } else {
       await node.render(refContext)
     }
-    refContext.pdf.endFormObject(ReferencesHandler.generateKey(id, color))
+    refContext.pdf.endFormObject(refContext.refsHandler.generateKey(id, color))
   }
 
   protected getBoundingBoxCore(context: Context): number[] {

test/common/tests.js

@@ -17,6 +17,7 @@ window.tests = [
   'complete-social-network',
   'custom-fonts',
   'display-none-and-visibility-inheritance',
+  'duplicate-ids',
   'empty-elements',
   'fill-and-stroke-inheritance',
   'fill-and-stroke-opacity',