[debug:hooks] Add command to display available in the system hooks.

config/services/debug.yml

@@ -147,3 +147,8 @@ services:
     arguments: ['@console.drupal_api']
     tags:
       - { name: drupal.command }
+  console.hook_debug:
+      class: Drupal\Console\Command\Debug\HookCommand
+      arguments: ['@console.extension_manager', '@module_handler']
+      tags:
+        - { name: drupal.command }

src/Command/Debug/HookCommand.php

@@ -0,0 +1,198 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Console\Command\Debug\HookCommand.
+ */
+
+namespace Drupal\Console\Command\Debug;
+
+use Drupal\Console\Core\Command\Command;
+use Drupal\Console\Extension\Manager;
+use Drupal\Component\Utility;
+use Drupal\Core\Extension\ModuleHandlerInterface;
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+use Symfony\Component\Finder\Finder;
+
+/**
+ * Class HookCommand.
+ *
+ * @package Drupal\Console\Command\Debug
+ */
+class HookCommand extends Command
+{
+    /**
+     * @var Manager $extensionManager
+     */
+    protected $extensionManager = null;
+
+    /**
+     * @var ModuleHandlerInterface
+     */
+    protected $moduleHandler;
+
+    /**
+     * @var array
+     */
+    protected $hooks = [];
+
+    /**
+     * HookCommand constructor.
+     *
+     * @param Manager $extensionManager
+     * @param ModuleHandlerInterface $moduleHandler
+     *
+     */
+    public function __construct(
+        Manager $extensionManager,
+        ModuleHandlerInterface $moduleHandler
+    ) {
+        $this->extensionManager = $extensionManager;
+        $this->moduleHandler = $moduleHandler;
+        parent::__construct();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function configure()
+    {
+        $this
+            ->setName('debug:hook')
+            ->setDescription($this->trans('commands.debug.hook.description'))
+            ->setAliases(['dbh']);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    protected function execute(InputInterface $input, OutputInterface $output)
+    {
+        $this->findHooks();
+        $tableHeader = [
+            $this->trans('commands.debug.hook.messages.name'),
+        ];
+
+        $this->getIo()->table($tableHeader, $this->getHooks(), 'compact');
+        return 0;
+    }
+
+    protected function findHooks()
+    {
+        $modules = $this->getAllModules();
+        $moduleInstances = [];
+        foreach ($modules as $module) {
+            $moduleInstance = $this->extensionManager->getModule($module);
+            if (empty($moduleInstance)) {
+                continue;
+            }
+            $moduleInstances[$module] = $moduleInstance;
+            $this->moduleHandler->setModuleList([$module => $moduleInstance]);
+            $this->findHooksInApiFile($moduleInstance);
+
+        }
+        $this->getHooksFromHookInfo($moduleInstances);
+    }
+
+    /**
+     * Get module of all modules in the system.
+     *
+     * @return array
+     *   Module list.
+     */
+    protected function getAllModules()
+    {
+        return $this->extensionManager->discoverModules()
+                    ->showInstalled()
+                    ->showUninstalled()
+                    ->showNoCore()
+                    ->showCore()
+                    ->getList(true);
+    }
+
+    /**
+     * Gets gooks from api file of the module.
+     *
+     * @param $moduleInstance
+     *   Module instance.
+     */
+    protected function findHooksInApiFile($moduleInstance)
+    {
+        $finder = new Finder();
+        $files = $finder->files()
+            ->name("{$moduleInstance->info['name']}.api.php")
+            ->in($moduleInstance->getPath());
+
+        foreach ($files as $file) {
+            $functions = $this->getFileFunctions($file->getPathname());
+            foreach ($functions as $function) {
+                if (Unicode::strpos($function, 'hook')) {
+                    $this->addHook($function);
+                }
+            }
+
+        }
+    }
+
+    /**
+     * Get names of all functions from file.
+     *
+     * @param string $filePath
+     *   File path
+     * @return array
+     *   Functions list.
+     */
+    protected function getFileFunctions($filePath)
+    {
+        $source = file_get_contents($filePath);
+        $tokens = token_get_all($source);
+
+        $functions = [];
+        $nextStringIsFunc = false;
+        foreach($tokens as $token) {
+            switch($token[0]) {
+                case T_FUNCTION:
+                    $nextStringIsFunc = true;
+                    break;
+
+                case T_STRING:
+                    if ($nextStringIsFunc) {
+                        $nextStringIsFunc = false;
+                        $functions[] = $token[1];
+                    }
+                    break;
+            }
+        }
+
+        return $functions;
+    }
+
+    /**
+     * @param $modules
+     */
+    protected function getHooksFromHookInfo($modules)
+    {
+        $this->moduleHandler->setModuleList($modules);
+        foreach(array_keys($this->moduleHandler->getHookInfo()) as $hook) {
+            $this->addHook('hook_' . $hook);
+        }
+    }
+
+    /**
+     * Add hook.
+     *
+     * @param string $value
+     *   Hook name.
+     */
+    protected function addHook($value)
+    {
+        $this->hooks[] = $value;
+    }
+
+    protected function getHooks()
+    {
+        return $this->hooks;
+    }
+}