Merge pull request #21652 from Snuffleupagus/signatures-async-helpers

Update the signatures-helpers to actually handle `MissingDataException`s

src/core/document.js

@@ -1996,7 +1996,7 @@ class PDFDocument {
     return shadow(this, "fieldObjects", promise);
   }
 
-  #collectSignatureFields(fields, out, visitedRefs) {
+  async #collectSignatureFields(fields, out, visitedRefs) {
     if (!Array.isArray(fields)) {
       return;
     }
@@ -2007,14 +2007,18 @@ class PDFDocument {
         }
         visitedRefs.put(fieldRef);
       }
-      const field = this.xref.fetchIfRef(fieldRef);
+      const field = await this.xref.fetchIfRefAsync(fieldRef);
       if (!(field instanceof Dict)) {
         continue;
       }
-      if (isName(field.get("FT"), "Sig")) {
+      if (isName(await field.getAsync("FT"), "Sig")) {
-        const sigDict = this.xref.fetchIfRef(field.get("V"));
+        const sigDict = await field.getAsync("V");
         if (sigDict instanceof Dict) {
-          const parsed = this.#parseSignatureDict(field, sigDict, fieldRef);
+          const parsed = await this.#parseSignatureDict(
+            field,
+            sigDict,
+            fieldRef
+          );
           if (parsed) {
             out.push(parsed);
           }
@@ -2023,7 +2027,11 @@ class PDFDocument {
       if (field.has("Kids")) {
         // A terminal field can have Widget annotations as children, so its
         // own signature must be collected before walking the field tree.
-        this.#collectSignatureFields(field.get("Kids"), out, visitedRefs);
+        await this.#collectSignatureFields(
+          await field.getAsync("Kids"),
+          out,
+          visitedRefs
+        );
       }
     }
   }
@@ -2070,8 +2078,8 @@ class PDFDocument {
     return true;
   }
 
-  #parseSignatureDict(field, sigDict, fieldRef) {
+  async #parseSignatureDict(field, sigDict, fieldRef) {
-    const byteRange = sigDict.get("ByteRange");
+    const byteRange = await sigDict.getAsync("ByteRange");
     if (
       !Array.isArray(byteRange) ||
       byteRange.length !== 4 ||
@@ -2079,31 +2087,13 @@ class PDFDocument {
     ) {
       return null;
     }
-    const contents = sigDict.get("Contents");
-    if (typeof contents !== "string" || contents.length === 0) {
-      return null;
-    }
-
-    const filterName = sigDict.get("Filter");
-    const filter = filterName instanceof Name ? filterName.name : null;
-    const subFilterName = sigDict.get("SubFilter");
-    const subFilter = subFilterName instanceof Name ? subFilterName.name : null;
-
-    let signatureType = null;
-    if (subFilter === "adbe.pkcs7.detached") {
-      signatureType = 0;
-    } else if (subFilter === "adbe.pkcs7.sha1") {
-      signatureType = 1;
-    }
-
     // Slice the two ByteRange byte spans out of the underlying PDF stream.
     // ByteRange = [a, b, c, d] means signed bytes are [a..a+b] and [c..c+d];
     // the gap covers the /Contents hex blob itself.
     const [a, b, c, d] = byteRange;
-    const stream = this.stream;
     // `/ByteRange` offsets are absolute, so compare against `stream.end`
     // (raw buffer end), not `stream.length` (post-`moveStart` payload).
-    const fileLength = stream.end || 0;
+    const fileLength = this.stream.end || 0;
     // Reject signatures whose /ByteRange is structurally implausible: it
     // must start at the file head, define a non-empty first span, leave
     // room for the /Contents blob between the two spans, and fit within
@@ -2118,22 +2108,46 @@ class PDFDocument {
     ) {
       return null;
     }
-    const pkcs7 = stringToBytes(contents);
 
-    const t = field.get("T");
+    const contents = await sigDict.getAsync("Contents");
-    const fieldName = typeof t === "string" ? stringToPDFString(t) : "";
+    if (typeof contents !== "string" || contents.length === 0) {
-    const name = sigDict.get("Name");
+      return null;
-    const reason = sigDict.get("Reason");
+    }
-    const location = sigDict.get("Location");
-    const contactInfo = sigDict.get("ContactInfo");
-    const m = sigDict.get("M");
 
+    const [
+      filterName,
+      subFilterName,
+      t,
+      name,
+      reason,
+      location,
+      contactInfo,
+      m,
+    ] = await Promise.all([
+      sigDict.getAsync("Filter"),
+      sigDict.getAsync("SubFilter"),
+      field.getAsync("T"),
+      sigDict.getAsync("Name"),
+      sigDict.getAsync("Reason"),
+      sigDict.getAsync("Location"),
+      sigDict.getAsync("ContactInfo"),
+      sigDict.getAsync("M"),
+    ]);
+
+    const filter = filterName instanceof Name ? filterName.name : null,
+      subFilter = subFilterName instanceof Name ? subFilterName.name : null;
+
+    let signatureType = null;
+    if (subFilter === "adbe.pkcs7.detached") {
+      signatureType = 0;
+    } else if (subFilter === "adbe.pkcs7.sha1") {
+      signatureType = 1;
+    }
     const refKey = fieldRef instanceof Ref ? fieldRef.toString() : "inline";
-    const id = `${refKey}:${a}-${b}-${c}-${d}`;
 
     return {
-      id,
+      id: `${refKey}:${a}-${b}-${c}-${d}`,
-      fieldName,
+      fieldName: typeof t === "string" ? stringToPDFString(t) : "",
       signerName: typeof name === "string" ? stringToPDFString(name) : null,
       reason: typeof reason === "string" ? stringToPDFString(reason) : null,
       location:
@@ -2145,7 +2159,7 @@ class PDFDocument {
       subFilter,
       signatureType,
       byteRange,
-      pkcs7,
+      pkcs7: stringToBytes(contents),
       revisionIndex: 0,
       parentId: null,
     };
@@ -2165,7 +2179,7 @@ class PDFDocument {
         const fields = annotationGlobals.acroForm.get("Fields");
 
         const collected = [];
-        this.#collectSignatureFields(fields, collected, new RefSet());
+        await this.#collectSignatureFields(fields, collected, new RefSet());
 
         await Promise.all(
           collected.map(async signature => {

test/unit/document_spec.js

@@ -322,6 +322,10 @@ describe("document", function () {
           { ref: sigRef, data: sigDict },
           { ref: fieldRef, data: fieldDict },
         ]);
+        acroForm.assignXref(xref);
+        sigDict.assignXref(xref);
+        fieldDict.assignXref(xref);
+
         acroForm.set("Fields", [fieldRef]);
 
         const pdfDocument = getDocument(acroForm, xref);
@@ -362,6 +366,10 @@ describe("document", function () {
           { ref: sigRef, data: sigDict },
           { ref: fieldRef, data: fieldDict },
         ]);
+        acroForm.assignXref(xref);
+        sigDict.assignXref(xref);
+        fieldDict.assignXref(xref);
+
         acroForm.set("Fields", [fieldRef]);
 
         const documentStream = new StringStream(
@@ -386,6 +394,10 @@ describe("document", function () {
           { ref: sigRef, data: sigDict },
           { ref: fieldRef, data: fieldDict },
         ]);
+        acroForm.assignXref(xref);
+        sigDict.assignXref(xref);
+        fieldDict.assignXref(xref);
+
         acroForm.set("Fields", [fieldRef]);
 
         const documentStream = new StringStream(
@@ -418,6 +430,11 @@ describe("document", function () {
           { ref: sigFieldRef, data: sigField },
           { ref: containerRef, data: container },
         ]);
+        acroForm.assignXref(xref);
+        sigDict.assignXref(xref);
+        sigField.assignXref(xref);
+        container.assignXref(xref);
+
         acroForm.set("Fields", [containerRef]);
 
         const pdfDocument = getDocument(acroForm, xref);
@@ -450,6 +467,11 @@ describe("document", function () {
           { ref: sigFieldRef, data: sigField },
           { ref: widgetRef, data: widget },
         ]);
+        acroForm.assignXref(xref);
+        sigDict.assignXref(xref);
+        sigField.assignXref(xref);
+        widget.assignXref(xref);
+
         acroForm.set("Fields", [sigFieldRef]);
 
         const pdfDocument = getDocument(acroForm, xref);
@@ -472,6 +494,10 @@ describe("document", function () {
           { ref: sigRef, data: sigDict },
           { ref: fieldRef, data: fieldDict },
         ]);
+        acroForm.assignXref(xref);
+        sigDict.assignXref(xref);
+        fieldDict.assignXref(xref);
+
         acroForm.set("Fields", [fieldRef]);
 
         const pdfDocument = getDocument(acroForm, xref);
@@ -498,18 +524,21 @@ describe("document", function () {
           name: "Inner",
         });
 
+        const outerField = makeSigField({ T: "outer", sigRef: outerSigRef });
+        const innerField = makeSigField({ T: "inner", sigRef: innerSigRef });
+
         const xref = new XRefMock([
           { ref: outerSigRef, data: outerSig },
-          {
+          { ref: outerFieldRef, data: outerField },
-            ref: outerFieldRef,
-            data: makeSigField({ T: "outer", sigRef: outerSigRef }),
-          },
           { ref: innerSigRef, data: innerSig },
-          {
+          { ref: innerFieldRef, data: innerField },
-            ref: innerFieldRef,
-            data: makeSigField({ T: "inner", sigRef: innerSigRef }),
-          },
         ]);
+        acroForm.assignXref(xref);
+        outerSig.assignXref(xref);
+        innerSig.assignXref(xref);
+        outerField.assignXref(xref);
+        innerField.assignXref(xref);
+
         acroForm.set("Fields", [outerFieldRef, innerFieldRef]);
 
         const pdfDocument = getDocument(acroForm, xref);
@@ -535,14 +564,18 @@ describe("document", function () {
             byteRange: [0, 10, 20, 30],
             subFilter,
           });
+          const sigField = makeSigField({ T: "sig", sigRef });
+
           const xref = new XRefMock([
             { ref: sigRef, data: sigDict },
-            {
+            { ref: fieldRef, data: sigField },
-              ref: fieldRef,
-              data: makeSigField({ T: "sig", sigRef }),
-            },
           ]);
+          acroForm.assignXref(xref);
+          sigDict.assignXref(xref);
+          sigField.assignXref(xref);
+
           acroForm.set("Fields", [fieldRef]);
+
           const pdfDocument = getDocument(acroForm, xref);
           const [sig] = await pdfDocument.signatures;
           return sig.signatureType;