Create absolute filter-URLs when needed in DOMFilterFactory (issue …

…18406)

This functionality is purposely limited to development mode and GENERIC builds, since it's unnecessary in e.g. the *built-in* Firefox PDF Viewer, and will only be used when a `<base>`-element is actually present.

*Please note:* We enforce relative filter-URLs when running tests, such that we test the same code as used in the Firefox PDF Viewer.

src/display/display_utils.js

@@ -49,6 +49,8 @@ class PixelsPerInch {
  * does the magic for us.
  */
 class DOMFilterFactory extends BaseFilterFactory {
+  #baseUrl;
+
   #_cache;
 
   #_defs;
@@ -121,6 +123,28 @@ class DOMFilterFactory extends BaseFilterFactory {
     return [bufferR.join(","), bufferG.join(","), bufferB.join(",")];
   }
 
+  #createUrl(id) {
+    if (
+      typeof PDFJSDev === "undefined" ||
+      PDFJSDev.test("GENERIC && !TESTING")
+    ) {
+      if (this.#baseUrl === undefined) {
+        const url = this.#document.URL;
+        if (url === this.#document.baseURI) {
+          // No `<base>`-element present, hence a relative URL should work.
+          this.#baseUrl = "";
+        } else if (isDataScheme(url)) {
+          warn('#createUrl: ignore "data:"-URL for performance reasons.');
+          this.#baseUrl = "";
+        } else {
+          this.#baseUrl = url.split("#", 1)[0];
+        }
+      }
+      return `url(${this.#baseUrl}#${id})`;
+    }
+    return `url(${id})`;
+  }
+
   addFilter(maps) {
     if (!maps) {
       return "none";
@@ -146,7 +170,7 @@ class DOMFilterFactory extends BaseFilterFactory {
     //  https://www.w3.org/TR/SVG11/filters.html#feComponentTransferElement
 
     const id = `g_${this.#docId}_transfer_map_${this.#id++}`;
-    const url = `url(#${id})`;
+    const url = this.#createUrl(id);
     this.#cache.set(maps, url);
     this.#cache.set(key, url);
 
@@ -232,7 +256,7 @@ class DOMFilterFactory extends BaseFilterFactory {
       filter
     );
 
-    info.url = `url(#${id})`;
+    info.url = this.#createUrl(id);
     return info.url;
   }
 
@@ -254,7 +278,7 @@ class DOMFilterFactory extends BaseFilterFactory {
     }
 
     const id = `g_${this.#docId}_alpha_map_${this.#id++}`;
-    const url = `url(#${id})`;
+    const url = this.#createUrl(id);
     this.#cache.set(map, url);
     this.#cache.set(key, url);
 
@@ -287,7 +311,7 @@ class DOMFilterFactory extends BaseFilterFactory {
     }
 
     const id = `g_${this.#docId}_luminosity_map_${this.#id++}`;
-    const url = `url(#${id})`;
+    const url = this.#createUrl(id);
     this.#cache.set(map, url);
     this.#cache.set(key, url);
 
@@ -389,7 +413,7 @@ class DOMFilterFactory extends BaseFilterFactory {
       filter
     );
 
-    info.url = `url(#${id})`;
+    info.url = this.#createUrl(id);
     return info.url;
   }