Fix for #434. Reworked the Document's object cache dictionary.

.github/workflows/performance.yml

@@ -0,0 +1,30 @@
+name: "Performance Tests"
+
+on:
+  pull_request:
+  push:
+    branches:
+      - "master"
+
+env:
+  fail-fast: true
+
+jobs:
+  performance-tests:
+    name: "Tests for the performance testing the PDF parsing"
+    runs-on: "ubuntu-20.04"
+
+    strategy:
+      matrix:
+        php:
+          - "7.4"
+
+    steps:
+      - name: "Checkout"
+        uses: "actions/checkout@v2"
+
+      - name: "Run composer for further autoloading"
+        run: "composer update"
+
+      - name: "Run performance tests"
+        run: "php tests/Performance/runPerformanceTests.php"

src/Smalot/PdfParser/Document.php

@@ -91,10 +91,26 @@ protected function buildDictionary()
         $this->dictionary = [];
 
         foreach ($this->objects as $id => $object) {
+            // Cache objects by type and subtype
             $type = $object->getHeader()->get('Type')->getContent();
 
-            if (!empty($type)) {
-                $this->dictionary[$type][$id] = $id;
+            if (null != $type) {
+                if (!isset($this->dictionary[$type])) {
+                    $this->dictionary[$type] = [
+                        'all' => [],
+                        'subtype' => [],
+                    ];
+                }
+
+                $this->dictionary[$type]['all'][$id] = $object;
+
+                $subtype = $object->getHeader()->get('Subtype')->getContent();
+                if (null != $subtype) {
+                    if (!isset($this->dictionary[$type]['subtype'][$subtype])) {
+                        $this->dictionary[$type]['subtype'][$subtype] = [];
+                    }
+                    $this->dictionary[$type]['subtype'][$subtype][$id] = $object;
+                }
             }
         }
     }
@@ -164,19 +180,26 @@ public function getObjectById(string $id)
         return null;
     }
 
+    public function hasObjectsByType(string $type, ?string $subtype = null): bool
+    {
+        return 0 < \count($this->getObjectsByType($type, $subtype));
+    }
+
     public function getObjectsByType(string $type, ?string $subtype = null): array
     {
-        $objects = [];
+        if (!isset($this->dictionary[$type])) {
+            return [];
+        }
 
-        foreach ($this->objects as $id => $object) {
-            if ($object->getHeader()->get('Type') == $type &&
-                (null === $subtype || $object->getHeader()->get('Subtype') == $subtype)
-            ) {
-                $objects[$id] = $object;
+        if (null != $subtype) {
+            if (!isset($this->dictionary[$type]['subtype'][$subtype])) {
+                return [];
             }
+
+            return $this->dictionary[$type]['subtype'][$subtype];
         }
 
-        return $objects;
+        return $this->dictionary[$type]['all'];
     }
 
     /**
@@ -187,25 +210,33 @@ public function getFonts()
         return $this->getObjectsByType('Font');
     }
 
+    public function getFirstFont(): ?Font
+    {
+        $fonts = $this->getFonts();
+
+        return reset($fonts);
+    }
+
     /**
      * @return Page[]
      *
      * @throws \Exception
      */
     public function getPages()
     {
-        if (isset($this->dictionary['Catalog'])) {
+        if ($this->hasObjectsByType('Catalog')) {
             // Search for catalog to list pages.
-            $id = reset($this->dictionary['Catalog']);
+            $catalogues = $this->getObjectsByType('Catalog');
+            $catalogue = reset($catalogues);
 
             /** @var Pages $object */
-            $object = $this->objects[$id]->get('Pages');
+            $object = $catalogue->get('Pages');
             if (method_exists($object, 'getPages')) {
                 return $object->getPages(true);
             }
         }
 
-        if (isset($this->dictionary['Pages'])) {
+        if ($this->hasObjectsByType('Pages')) {
             // Search for pages to list kids.
             $pages = [];
 
@@ -218,7 +249,7 @@ public function getPages()
             return $pages;
         }
 
-        if (isset($this->dictionary['Page'])) {
+        if ($this->hasObjectsByType('Page')) {
             // Search for 'page' (unordered pages).
             $pages = $this->getObjectsByType('Page');
 

src/Smalot/PdfParser/Encoding.php

@@ -120,9 +120,7 @@ public function translateChar($dec): int
     }
 
     /**
-     * Returns the name of the encoding class, if available.
-     *
-     * @return string Returns encoding class name if available or empty string (only prior PHP 7.4).
+     * Returns encoding class name if available or empty string (only prior PHP 7.4).
      *
      * @throws \Exception On PHP 7.4+ an exception is thrown if encoding class doesn't exist.
      */

src/Smalot/PdfParser/Header.php

@@ -120,7 +120,7 @@ public function getDetails(bool $deep = true): array
     /**
      * Indicate if an element name is available in header.
      *
-     *  @param string $name the name of the element
+     * @param string $name the name of the element
      */
     public function has(string $name): bool
     {

src/Smalot/PdfParser/PDFObject.php

@@ -222,7 +222,7 @@ private function getDefaultFont(Page $page = null): Font
             $fonts = $page->getFonts();
         }
 
-        $fonts = array_merge($fonts, array_values($this->document->getFonts()));
+        $fonts[] = $this->document->getFirstFont();
 
         if (\count($fonts) > 0) {
             return reset($fonts);

src/Smalot/PdfParser/Page.php

@@ -263,7 +263,7 @@ public function getTextArray(self $page = null): array
     /**
      * Gets all the text data with its internal representation of the page.
      *
-     * @return array An array with the data and the internal representation
+     * Returns an array with the data and the internal representation
      */
     public function extractRawData(): array
     {

tests/Integration/DocumentTest.php

@@ -117,8 +117,8 @@ public function testDictionary()
 
         $objects = $document->getDictionary();
         $this->assertEquals(1, \count($objects));
-        $this->assertEquals(1, \count($objects['Page']));
-        $this->assertEquals(2, $objects['Page'][2]);
+        $this->assertEquals(1, \count($objects['Page']['all']));
+        $this->assertEquals($object2, $objects['Page']['all'][2]);
     }
 
     public function testGetObjectsByType()

tests/Performance/Exception/PerformanceFailException.php

@@ -0,0 +1,7 @@
+<?php
+
+namespace Tests\Smalot\PdfParser\Performance\Exception;
+
+class PerformanceFailException extends \Exception
+{
+}

tests/Performance/Test/AbstractPerformanceTest.php

@@ -0,0 +1,21 @@
+<?php
+
+namespace Tests\Smalot\PdfParser\Performance\Test;
+
+abstract class AbstractPerformanceTest
+{
+    /**
+     * Initializes the test (eg, fetches the files etc).
+     */
+    abstract public function init(): void;
+
+    /**
+     * Executes the test.
+     */
+    abstract public function run(): void;
+
+    /**
+     * Returns the time over which the test is considered a fail.
+     */
+    abstract public function getMaxEstimatedTime(): int;
+}

tests/Performance/Test/DocumentDictionaryCacheTest.php

@@ -0,0 +1,83 @@
+<?php
+
+/**
+ * @file This file is part of the PdfParser library.
+ *
+ * @author  Konrad Abicht <[email protected]>
+ * @date    2020-06-01
+ *
+ * @author  Sébastien MALOT <[email protected]>
+ * @date    2017-01-03
+ *
+ * @license LGPLv3
+ * @url     <https://github.com/smalot/pdfparser>
+ *
+ *  PdfParser is a pdf library written in PHP, extraction oriented.
+ *  Copyright (C) 2017 - Sébastien MALOT <[email protected]>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Lesser General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public License
+ *  along with this program.
+ *  If not, see <http://www.pdfparser.org/sites/default/LICENSE.txt>.
+ */
+
+namespace Tests\Smalot\PdfParser\Performance\Test;
+
+use Smalot\PdfParser\Page;
+use Smalot\PdfParser\Parser;
+
+/**
+ * This test checks does a performance test with certain PDF files that extensively use
+ * the getFirstFont() method of Document.php. If Document.php correctly uses a dictionary
+ * to cache the objects inside the PDF file, then the parsing should be quick.
+ * If it does not, the parsing can be extensively slow or even crash.
+ */
+class DocumentDictionaryCacheTest extends AbstractPerformanceTest
+{
+    /**
+     * @var Parser
+     */
+    protected $parser;
+    protected $data;
+
+    public function init(): void
+    {
+        $this->parser = new Parser();
+
+        // load PDF file content
+        $this->data = file_get_contents(__DIR__.'/../../../samples/DocumentWithLotsOfObjects.pdf');
+    }
+
+    public function run(): void
+    {
+        // give PDF content to function and parse it
+        $pdf = $this->parser->parseContent($this->data);
+
+        $pages = $pdf->getPages();
+
+        foreach ($pages as $i => $page) { /* @var $page Page */
+            if ($i < 77) {
+                continue;
+            }
+            if ($i > 78) {
+                continue;
+            }
+
+            $page->getText(); // Test this method
+        }
+    }
+
+    public function getMaxEstimatedTime(): int
+    {
+        return 20;
+    }
+}

tests/Performance/runPerformanceTests.php

@@ -0,0 +1,21 @@
+<?php
+
+require __DIR__.'/../../vendor/autoload.php';
+
+$tests = [
+    new \Tests\Smalot\PdfParser\Performance\Test\DocumentDictionaryCacheTest(),
+];
+
+foreach ($tests as $test) { /* @var $test \Tests\Smalot\PdfParser\Performance\Test\AbstractPerformanceTest */
+    $test->init();
+
+    $startTime = microtime(true);
+    $test->run();
+    $endTime = microtime(true);
+
+    $time = $endTime - $startTime;
+
+    if ($test->getMaxEstimatedTime() <= $time) {
+        throw new \Tests\Smalot\PdfParser\Performance\Exception\PerformanceFailException(sprintf('Performance failed on test "%s". Time taken was %.2f seconds, expected less than %d seconds.', get_class($test), $time, $test->getMaxEstimatedTime()));
+    }
+}