From 7728a6630c63492ed56f2adb65b919f689522286 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Fri, 16 Aug 2019 10:20:43 +0200
Subject: [PATCH 1/2] Inline the `isString` check in the `Parser.getObj` method

For very large and complex PDF files this will help performance *slightly*, since `Parser.getObj` is called *a lot* during parsing in the worker.

This patch was tested using the PDF file from issue 2618, i.e. http://bugzilla-attachments.gnome.org/attachment.cgi?id=226471, with the following manifest file:
```
[
    {  "id": "issue2618",
       "file": "../web/pdfs/issue2618.pdf",
       "md5": "",
       "rounds": 200,
       "type": "eq"
    }
]
```

which gave the following results when comparing this patch against the `master` branch:
```
-- Grouped By browser, stat --
browser | stat         | Count | Baseline(ms) | Current(ms) | +/- |    %  | Result(P<.05)
------- | ------------ | ----- | ------------ | ----------- | --- | ----- | -------------
Firefox | Overall      |   200 |         2847 |        2830 | -17 | -0.60 |        faster
Firefox | Page Request |   200 |            2 |           2 |   0 | -7.14 |
Firefox | Rendering    |   200 |         2844 |        2827 | -17 | -0.60 |        faster
```
---
 src/core/parser.js | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/core/parser.js b/src/core/parser.js
index db50e06f8..8c895136e 100644
--- a/src/core/parser.js
+++ b/src/core/parser.js
@@ -19,8 +19,7 @@ import {
   PredictorStream, RunLengthStream
 } from './stream';
 import {
-  assert, bytesToString, FormatError, info, isNum, isSpace, isString,
-  StreamType, warn
+  assert, bytesToString, FormatError, info, isNum, isSpace, StreamType, warn
 } from '../shared/util';
 import {
   Cmd, Dict, EOF, isCmd, isDict, isEOF, isName, Name, Ref
@@ -158,7 +157,7 @@ class Parser {
       return num;
     }
 
-    if (isString(buf1)) { // string
+    if (typeof buf1 === 'string') {
       let str = buf1;
       if (cipherTransform) {
         str = cipherTransform.decryptString(str);

From 40d3916f3110343e1b9db67455e28d49c19856f5 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Fri, 16 Aug 2019 13:47:12 +0200
Subject: [PATCH 2/2] Reduce the number of temporary variables in the
 `Parser.getObj` method

This avoids allocating approximately 1.7 million short-lived variables when loading the PDF file from issue 2618, i.e. http://bugzilla-attachments.gnome.org/attachment.cgi?id=226471, in the default viewer.
---
 src/core/parser.js | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/src/core/parser.js b/src/core/parser.js
index 8c895136e..176884296 100644
--- a/src/core/parser.js
+++ b/src/core/parser.js
@@ -89,7 +89,7 @@ class Parser {
     }
   }
 
-  getObj(cipherTransform) {
+  getObj(cipherTransform = null) {
     const buf1 = this.buf1;
     this.shift();
 
@@ -147,22 +147,20 @@ class Parser {
     }
 
     if (Number.isInteger(buf1)) { // indirect reference or integer
-      const num = buf1;
       if (Number.isInteger(this.buf1) && isCmd(this.buf2, 'R')) {
-        const ref = Ref.get(num, this.buf1);
+        const ref = Ref.get(buf1, this.buf1);
         this.shift();
         this.shift();
         return ref;
       }
-      return num;
+      return buf1;
     }
 
     if (typeof buf1 === 'string') {
-      let str = buf1;
       if (cipherTransform) {
-        str = cipherTransform.decryptString(str);
+        return cipherTransform.decryptString(buf1);
       }
-      return str;
+      return buf1;
     }
 
     // simple object