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Slightly simplify the XRef cache lookup in XRef.fetch

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Note that the XRef cache will only hold objects returned through `Parser.getObj`, and indirectly via `Lexer.getObj`. Since neither of those methods will ever return `undefined`, we can simply `assert` that when inserting objects into the cache and thus get rid of one function call when doing cache lookups.

Obviously this won't have a huge effect on performance, however `XRef.fetch` is usually called *a lot* in larger documents and this patch thus cannot hurt.
This commit is contained in:
Jonas Jenwald 2019-11-30 13:12:48 +01:00
parent 62ec8109b5
commit c3b1c8f857
1 changed files with 15 additions and 2 deletions
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17
src/core/obj.js
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@ -1636,8 +1636,11 @@ var XRef = (function XRefClosure() {
} }
const num = ref.num; const num = ref.num;
if (this._cacheMap.has(num)) { // The XRef cache is populated with objects which are obtained through
const cacheEntry = this._cacheMap.get(num); // `Parser.getObj`, and indirectly via `Lexer.getObj`. Neither of these
// methods should ever return `undefined` (note the `assert` calls below).
const cacheEntry = this._cacheMap.get(num);
if (cacheEntry !== undefined) {
// In documents with Object Streams, it's possible that cached `Dict`s // In documents with Object Streams, it's possible that cached `Dict`s
// have not been assigned an `objId` yet (see e.g. issue3115r.pdf). // have not been assigned an `objId` yet (see e.g. issue3115r.pdf).
if (cacheEntry instanceof Dict && !cacheEntry.objId) { if (cacheEntry instanceof Dict && !cacheEntry.objId) {
@ -1701,6 +1704,11 @@ var XRef = (function XRefClosure() {
xrefEntry = parser.getObj(); xrefEntry = parser.getObj();
} }
if (!isStream(xrefEntry)) { if (!isStream(xrefEntry)) {
if (typeof PDFJSDev === 'undefined' ||
PDFJSDev.test('!PRODUCTION || TESTING')) {
assert(xrefEntry !== undefined,
'fetchUncompressed: The "xrefEntry" cannot be undefined.');
}
this._cacheMap.set(num, xrefEntry); this._cacheMap.set(num, xrefEntry);
} }
return xrefEntry; return xrefEntry;
@ -1753,6 +1761,11 @@ var XRef = (function XRefClosure() {
} }
const num = nums[i], entry = this.entries[num]; const num = nums[i], entry = this.entries[num];
if (entry && entry.offset === tableOffset && entry.gen === i) { if (entry && entry.offset === tableOffset && entry.gen === i) {
if (typeof PDFJSDev === 'undefined' ||
PDFJSDev.test('!PRODUCTION || TESTING')) {
assert(obj !== undefined,
'fetchCompressed: The "obj" cannot be undefined.');
}
this._cacheMap.set(num, obj); this._cacheMap.set(num, obj);
} }
} }