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Get the field name from its parent when it doesn't have one when collecting fields (bug 1864136)

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Some fields, somewhere under the Fields entry in Acroform, could have no name (in T)
but with a parent which has a name but which isn't somewhere under Fields.
As a side-effect, this patch prevents infinite loops because of potential cycles
under Fields.
This commit is contained in:
Calixte Denizet 2023-11-13 11:05:03 +01:00
parent 7884119975
commit 09b4fe6a30
3 changed files with 118 additions and 4 deletions
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42
src/core/document.js
View file

@ -1711,12 +1711,19 @@ class PDFDocument {
: clearGlobalCaches();
}
async #collectFieldObjects(name, fieldRef, promises, annotationGlobals) {
async #collectFieldObjects(
name,
fieldRef,
promises,
annotationGlobals,
visitedRefs
) {
const { xref } = this;
if (!(fieldRef instanceof Ref)) {
if (!(fieldRef instanceof Ref) || visitedRefs.has(fieldRef)) {
return;
}
visitedRefs.put(fieldRef);
const field = await xref.fetchAsync(fieldRef);
if (!(field instanceof Dict)) {
return;
@ -1724,6 +1731,25 @@ class PDFDocument {
if (field.has("T")) {
const partName = stringToPDFString(await field.getAsync("T"));
name = name === "" ? partName : `${name}.${partName}`;
} else {
let obj = field;
while (true) {
obj = obj.getRaw("Parent");
if (obj instanceof Ref) {
if (visitedRefs.has(obj)) {
break;
}
obj = await xref.fetchAsync(obj);
}
if (!(obj instanceof Dict)) {
break;
}
if (obj.has("T")) {
const partName = stringToPDFString(await obj.getAsync("T"));
name = name === "" ? partName : `${name}.${partName}`;
break;
}
}
}
if (!promises.has(name)) {
@ -1751,7 +1777,13 @@ class PDFDocument {
const kids = await field.getAsync("Kids");
if (Array.isArray(kids)) {
for (const kid of kids) {
await this.#collectFieldObjects(name, kid, promises, annotationGlobals);
await this.#collectFieldObjects(
name,
kid,
promises,
annotationGlobals,
visitedRefs
);
}
}
}
@ -1769,6 +1801,7 @@ class PDFDocument {
return null;
}
const visitedRefs = new RefSet();
const allFields = Object.create(null);
const fieldPromises = new Map();
for (const fieldRef of await acroForm.getAsync("Fields")) {
@ -1776,7 +1809,8 @@ class PDFDocument {
"",
fieldRef,
fieldPromises,
annotationGlobals
annotationGlobals,
visitedRefs
);
}