Add attachments when merging/reorganizing a pdf (bug 2026956)

src/core/catalog.js

@@ -1084,6 +1084,15 @@ class Catalog {
     return shadow(this, "attachments", attachments);
   }
 
+  get rawEmbeddedFiles() {
+    const obj = this.#catDict.get("Names");
+    if (!(obj instanceof Dict) || !obj.has("EmbeddedFiles")) {
+      return null;
+    }
+    const nameTree = new NameTree(obj.getRaw("EmbeddedFiles"), this.xref);
+    return nameTree.getAll(/* isRaw = */ true);
+  }
+
   get xfaImages() {
     const obj = this.#catDict.get("Names");
     let xfaImages = null;

src/core/editor/pdf_editor.js

@@ -76,6 +76,7 @@ class DocumentData {
     this.hasSignatureAnnotations = false;
     this.fieldToParent = new RefSetCache();
     this.outline = null;
+    this.embeddedFiles = null;
   }
 }
 
@@ -163,6 +164,8 @@ class PDFEditor {
 
   outlineItems = null;
 
+  embeddedFiles = new Map();
+
   constructor({ useObjectStreams = true, title = "", author = "" } = {}) {
     [this.rootRef, this.rootDict] = this.newDict;
     [this.infoRef, this.infoDict] = this.newDict;
@@ -694,6 +697,7 @@ class PDFEditor {
     await this.#mergeStructTrees(allDocumentData);
     await this.#mergeAcroForms(allDocumentData);
     this.#buildOutline(allDocumentData);
+    await this.#collectEmbeddedFiles(allDocumentData);
 
     return this.writePDF();
   }
@@ -723,6 +727,9 @@ class PDFEditor {
       pdfManager
         .ensureCatalog("documentOutlineForEditor")
         .then(outline => (documentData.outline = outline)),
+      pdfManager
+        .ensureCatalog("rawEmbeddedFiles")
+        .then(ef => (documentData.embeddedFiles = ef)),
     ]);
     const structTreeRoot = documentData.structTreeRoot;
     if (structTreeRoot) {
@@ -2078,13 +2085,15 @@ class PDFEditor {
     const maxLeaves =
       MAX_IN_NAME_TREE_NODE <= 1 ? allEntries.length : MAX_IN_NAME_TREE_NODE;
     const [treeRef, treeDict] = this.newDict;
-    const stack = [{ dict: treeDict, entries: allEntries }];
+    const stack = [{ dict: treeDict, entries: allEntries, isRoot: true }];
     const valueType = areNames ? "Names" : "Nums";
 
     while (stack.length > 0) {
-      const { dict, entries } = stack.pop();
+      const { dict, entries, isRoot } = stack.pop();
       if (entries.length <= maxLeaves) {
-        dict.set("Limits", [entries[0][0], entries.at(-1)[0]]);
+        if (!isRoot) {
+          dict.set("Limits", [entries[0][0], entries.at(-1)[0]]);
+        }
         dict.set(valueType, entries.flat());
         continue;
       }
@@ -2124,6 +2133,63 @@ class PDFEditor {
     rootDict.set("PageLabels", pageLabelsRef);
   }
 
+  /**
+   * Collect and clone EmbeddedFiles from all source documents.
+   * @param {Array<DocumentData>} allDocumentData
+   */
+  async #collectEmbeddedFiles(allDocumentData) {
+    const { embeddedFiles } = this;
+    for (const documentData of allDocumentData) {
+      const {
+        embeddedFiles: docEmbeddedFiles,
+        document: { xref },
+      } = documentData;
+      if (!docEmbeddedFiles?.size) {
+        continue;
+      }
+      this.currentDocument = documentData;
+      for (const [key, valueRef] of docEmbeddedFiles) {
+        let name = key;
+        if (embeddedFiles.has(name)) {
+          const displayName = stringToPDFString(
+            key,
+            /* keepEscapeSequence = */ true
+          );
+          for (let i = 1; ; i++) {
+            const deduped = `${displayName}_${i}`;
+            if (!embeddedFiles.has(deduped)) {
+              name = deduped;
+              break;
+            }
+          }
+        }
+        embeddedFiles.set(
+          name,
+          await this.#collectDependencies(valueRef, true, xref)
+        );
+      }
+      this.currentDocument = null;
+    }
+  }
+
+  #makeEmbeddedFilesTree() {
+    const { embeddedFiles } = this;
+    if (embeddedFiles.size === 0) {
+      return;
+    }
+    if (!this.namesDict) {
+      [this.namesRef, this.namesDict] = this.newDict;
+      this.rootDict.set("Names", this.namesRef);
+    }
+    this.namesDict.set(
+      "EmbeddedFiles",
+      this.#makeNameNumTree(
+        Array.from(embeddedFiles.entries()),
+        /* areNames = */ true
+      )
+    );
+  }
+
   #makeDestinationsTree() {
     const { namedDestinations } = this;
     if (namedDestinations.size === 0) {
@@ -2245,6 +2311,7 @@ class PDFEditor {
     this.#makeAcroForm();
     this.#makePageTree();
     this.#makePageLabelsTree();
+    this.#makeEmbeddedFilesTree();
     this.#makeDestinationsTree();
     this.#makeStructTree();
     await this.#makeOutline();

test/unit/api_spec.js

@@ -6429,6 +6429,71 @@ small scripts as well as for`);
 
         await loadingTask.destroy();
       });
+
+      it("preserves EmbeddedFiles (attachments) when extracting pages", async function () {
+        let loadingTask = getDocument(buildGetDocumentParams("attachment.pdf"));
+        let pdfDoc = await loadingTask.promise;
+
+        // Verify the original document has the expected attachment.
+        const originalAttachments = await pdfDoc.getAttachments();
+        expect(originalAttachments["foo.txt"]).toBeDefined();
+
+        const data = await pdfDoc.extractPages([
+          { document: null, includePages: [0] },
+        ]);
+        await loadingTask.destroy();
+
+        loadingTask = getDocument(data);
+        pdfDoc = await loadingTask.promise;
+
+        const attachments = await pdfDoc.getAttachments();
+        expect(attachments).not.toBeNull();
+        expect(attachments["foo.txt"]).toEqual({
+          rawFilename: "foo.txt",
+          filename: "foo.txt",
+          content: new Uint8Array([98, 97, 114, 32, 98, 97, 122, 32, 10]),
+          description: "",
+        });
+
+        await loadingTask.destroy();
+      });
+
+      it("preserves EmbeddedFiles (attachments) when merging two PDFs", async function () {
+        let loadingTask = getDocument(buildGetDocumentParams("attachment.pdf"));
+        let pdfDoc = await loadingTask.promise;
+
+        // Merge attachment.pdf with itself: both copies carry "foo.txt", so
+        // the second one should be deduplicated to "foo.txt_1".
+        const data = await pdfDoc.extractPages([
+          { document: null },
+          { document: null },
+        ]);
+        await loadingTask.destroy();
+
+        loadingTask = getDocument(data);
+        pdfDoc = await loadingTask.promise;
+
+        const attachments = await pdfDoc.getAttachments();
+        expect(attachments).not.toBeNull();
+
+        const expectedContent = new Uint8Array([
+          98, 97, 114, 32, 98, 97, 122, 32, 10,
+        ]);
+        expect(attachments["foo.txt"]).toEqual({
+          rawFilename: "foo.txt",
+          filename: "foo.txt",
+          content: expectedContent,
+          description: "",
+        });
+        expect(attachments["foo.txt_1"]).toEqual({
+          rawFilename: "foo.txt",
+          filename: "foo.txt",
+          content: expectedContent,
+          description: "",
+        });
+
+        await loadingTask.destroy();
+      });
     });
 
     describe("AcroForm", function () {