comparison vendor/psy/psysh/src/Shell.php @ 13:5fb285c0d0e3

Update Drupal core to 8.4.7 via Composer. Security update; I *think* we've
been lucky to get away with this so far, as we don't support self-registration
which seems to be used by the so-called "drupalgeddon 2" attack that 8.4.5
was vulnerable to.

+<?php
+
+/*
+ * This file is part of Psy Shell.
+ *
+ * (c) 2012-2018 Justin Hileman
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Psy;
+
+use Psy\CodeCleaner\NoReturnValue;
+use Psy\Exception\BreakException;
+use Psy\Exception\ErrorException;
+use Psy\Exception\Exception as PsyException;
+use Psy\Exception\ThrowUpException;
+use Psy\Exception\TypeErrorException;
+use Psy\ExecutionLoop\ProcessForker;
+use Psy\ExecutionLoop\RunkitReloader;
+use Psy\Input\ShellInput;
+use Psy\Input\SilentInput;
+use Psy\Output\ShellOutput;
+use Psy\TabCompletion\Matcher;
+use Psy\VarDumper\PresenterAware;
+use Symfony\Component\Console\Application;
+use Symfony\Component\Console\Command\Command as BaseCommand;
+use Symfony\Component\Console\Formatter\OutputFormatter;
+use Symfony\Component\Console\Input\ArgvInput;
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputDefinition;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Input\InputOption;
+use Symfony\Component\Console\Input\StringInput;
+use Symfony\Component\Console\Output\OutputInterface;
+
+/**
+ * The Psy Shell application.
+ *
+ * Usage:
+ *
+ *     $shell = new Shell;
+ *     $shell->run();
+ *
+ * @author Justin Hileman <[e-mail]>
+ */
+class Shell extends Application
+{
+    const VERSION = 'v0.9.3';
+
+    const PROMPT      = '>>> ';
+    const BUFF_PROMPT = '... ';
+    const REPLAY      = '--> ';
+    const RETVAL      = '=> ';
+
+    private $config;
+    private $cleaner;
+    private $output;
+    private $readline;
+    private $inputBuffer;
+    private $code;
+    private $codeBuffer;
+    private $codeBufferOpen;
+    private $codeStack;
+    private $stdoutBuffer;
+    private $context;
+    private $includes;
+    private $loop;
+    private $outputWantsNewline = false;
+    private $prompt;
+    private $loopListeners;
+    private $autoCompleter;
+    private $matchers = [];
+    private $commandsMatcher;
+
+    /**
+     * Create a new Psy Shell.
+     *
+     * @param Configuration $config (default: null)
+     */
+    public function __construct(Configuration $config = null)
+    {
+        $this->config        = $config ?: new Configuration();
+        $this->cleaner       = $this->config->getCodeCleaner();
+        $this->loop          = new ExecutionLoop();
+        $this->context       = new Context();
+        $this->includes      = [];
+        $this->readline      = $this->config->getReadline();
+        $this->inputBuffer   = [];
+        $this->codeStack     = [];
+        $this->stdoutBuffer  = '';
+        $this->loopListeners = $this->getDefaultLoopListeners();
+
+        parent::__construct('Psy Shell', self::VERSION);
+
+        $this->config->setShell($this);
+
+        // Register the current shell session's config with \Psy\info
+        \Psy\info($this->config);
+    }
+
+    /**
+     * Check whether the first thing in a backtrace is an include call.
+     *
+     * This is used by the psysh bin to decide whether to start a shell on boot,
+     * or to simply autoload the library.
+     */
+    public static function isIncluded(array $trace)
+    {
+        return isset($trace[0]['function']) &&
+          in_array($trace[0]['function'], ['require', 'include', 'require_once', 'include_once']);
+    }
+
+    /**
+     * Invoke a Psy Shell from the current context.
+     *
+     * @see Psy\debug
+     * @deprecated will be removed in 1.0. Use \Psy\debug instead
+     *
+     * @param array  $vars        Scope variables from the calling context (default: array())
+     * @param object $boundObject Bound object ($this) value for the shell
+     *
+     * @return array Scope variables from the debugger session
+     */
+    public static function debug(array $vars = [], $boundObject = null)
+    {
+        return \Psy\debug($vars, $boundObject);
+    }
+
+    /**
+     * Adds a command object.
+     *
+     * {@inheritdoc}
+     *
+     * @param BaseCommand $command A Symfony Console Command object
+     *
+     * @return BaseCommand The registered command
+     */
+    public function add(BaseCommand $command)
+    {
+        if ($ret = parent::add($command)) {
+            if ($ret instanceof ContextAware) {
+                $ret->setContext($this->context);
+            }
+
+            if ($ret instanceof PresenterAware) {
+                $ret->setPresenter($this->config->getPresenter());
+            }
+
+            if (isset($this->commandsMatcher)) {
+                $this->commandsMatcher->setCommands($this->all());
+            }
+        }
+
+        return $ret;
+    }
+
+    /**
+     * Gets the default input definition.
+     *
+     * @return InputDefinition An InputDefinition instance
+     */
+    protected function getDefaultInputDefinition()
+    {
+        return new InputDefinition([
+            new InputArgument('command', InputArgument::REQUIRED, 'The command to execute'),
+            new InputOption('--help', '-h', InputOption::VALUE_NONE, 'Display this help message.'),
+        ]);
+    }
+
+    /**
+     * Gets the default commands that should always be available.
+     *
+     * @return array An array of default Command instances
+     */
+    protected function getDefaultCommands()
+    {
+        $sudo = new Command\SudoCommand();
+        $sudo->setReadline($this->readline);
+
+        $hist = new Command\HistoryCommand();
+        $hist->setReadline($this->readline);
+
+        return [
+            new Command\HelpCommand(),
+            new Command\ListCommand(),
+            new Command\DumpCommand(),
+            new Command\DocCommand(),
+            new Command\ShowCommand($this->config->colorMode()),
+            new Command\WtfCommand($this->config->colorMode()),
+            new Command\WhereamiCommand($this->config->colorMode()),
+            new Command\ThrowUpCommand(),
+            new Command\TimeitCommand(),
+            new Command\TraceCommand(),
+            new Command\BufferCommand(),
+            new Command\ClearCommand(),
+            new Command\EditCommand($this->config->getRuntimeDir()),
+            // new Command\PsyVersionCommand(),
+            $sudo,
+            $hist,
+            new Command\ExitCommand(),
+        ];
+    }
+
+    /**
+     * @return array
+     */
+    protected function getDefaultMatchers()
+    {
+        // Store the Commands Matcher for later. If more commands are added,
+        // we'll update the Commands Matcher too.
+        $this->commandsMatcher = new Matcher\CommandsMatcher($this->all());
+
+        return [
+            $this->commandsMatcher,
+            new Matcher\KeywordsMatcher(),
+            new Matcher\VariablesMatcher(),
+            new Matcher\ConstantsMatcher(),
+            new Matcher\FunctionsMatcher(),
+            new Matcher\ClassNamesMatcher(),
+            new Matcher\ClassMethodsMatcher(),
+            new Matcher\ClassAttributesMatcher(),
+            new Matcher\ObjectMethodsMatcher(),
+            new Matcher\ObjectAttributesMatcher(),
+            new Matcher\ClassMethodDefaultParametersMatcher(),
+            new Matcher\ObjectMethodDefaultParametersMatcher(),
+            new Matcher\FunctionDefaultParametersMatcher(),
+        ];
+    }
+
+    /**
+     * @deprecated Nothing should use this anymore
+     */
+    protected function getTabCompletionMatchers()
+    {
+        @trigger_error('getTabCompletionMatchers is no longer used', E_USER_DEPRECATED);
+    }
+
+    /**
+     * Gets the default command loop listeners.
+     *
+     * @return array An array of Execution Loop Listener instances
+     */
+    protected function getDefaultLoopListeners()
+    {
+        $listeners = [];
+
+        if (ProcessForker::isSupported() && $this->config->usePcntl()) {
+            $listeners[] = new ProcessForker();
+        }
+
+        if (RunkitReloader::isSupported()) {
+            $listeners[] = new RunkitReloader();
+        }
+
+        return $listeners;
+    }
+
+    /**
+     * Add tab completion matchers.
+     *
+     * @param array $matchers
+     */
+    public function addMatchers(array $matchers)
+    {
+        $this->matchers = array_merge($this->matchers, $matchers);
+
+        if (isset($this->autoCompleter)) {
+            $this->addMatchersToAutoCompleter($matchers);
+        }
+    }
+
+    /**
+     * @deprecated Call `addMatchers` instead
+     *
+     * @param array $matchers
+     */
+    public function addTabCompletionMatchers(array $matchers)
+    {
+        $this->addMatchers($matchers);
+    }
+
+    /**
+     * Set the Shell output.
+     *
+     * @param OutputInterface $output
+     */
+    public function setOutput(OutputInterface $output)
+    {
+        $this->output = $output;
+    }
+
+    /**
+     * Runs the current application.
+     *
+     * @param InputInterface  $input  An Input instance
+     * @param OutputInterface $output An Output instance
+     *
+     * @return int 0 if everything went fine, or an error code
+     */
+    public function run(InputInterface $input = null, OutputInterface $output = null)
+    {
+        $this->initializeTabCompletion();
+
+        if ($input === null && !isset($_SERVER['argv'])) {
+            $input = new ArgvInput([]);
+        }
+
+        if ($output === null) {
+            $output = $this->config->getOutput();
+        }
+
+        try {
+            return parent::run($input, $output);
+        } catch (\Exception $e) {
+            $this->writeException($e);
+        }
+
+        return 1;
+    }
+
+    /**
+     * Runs the current application.
+     *
+     * @throws Exception if thrown via the `throw-up` command
+     *
+     * @param InputInterface  $input  An Input instance
+     * @param OutputInterface $output An Output instance
+     *
+     * @return int 0 if everything went fine, or an error code
+     */
+    public function doRun(InputInterface $input, OutputInterface $output)
+    {
+        $this->setOutput($output);
+
+        $this->resetCodeBuffer();
+
+        $this->setAutoExit(false);
+        $this->setCatchExceptions(false);
+
+        $this->readline->readHistory();
+
+        $this->output->writeln($this->getHeader());
+        $this->writeVersionInfo();
+        $this->writeStartupMessage();
+
+        try {
+            $this->beforeRun();
+            $this->loop->run($this);
+            $this->afterRun();
+        } catch (ThrowUpException $e) {
+            throw $e->getPrevious();
+        } catch (BreakException $e) {
+            // The ProcessForker throws a BreakException to finish the main thread.
+            return;
+        }
+    }
+
+    /**
+     * Read user input.
+     *
+     * This will continue fetching user input until the code buffer contains
+     * valid code.
+     *
+     * @throws BreakException if user hits Ctrl+D
+     */
+    public function getInput()
+    {
+        $this->codeBufferOpen = false;
+
+        do {
+            // reset output verbosity (in case it was altered by a subcommand)
+            $this->output->setVerbosity(ShellOutput::VERBOSITY_VERBOSE);
+
+            $input = $this->readline();
+
+            /*
+             * Handle Ctrl+D. It behaves differently in different cases:
+             *
+             *   1) In an expression, like a function or "if" block, clear the input buffer
+             *   2) At top-level session, behave like the exit command
+             */
+            if ($input === false) {
+                $this->output->writeln('');
+
+                if ($this->hasCode()) {
+                    $this->resetCodeBuffer();
+                } else {
+                    throw new BreakException('Ctrl+D');
+                }
+            }
+
+            // handle empty input
+            if (trim($input) === '') {
+                continue;
+            }
+
+            $input = $this->onInput($input);
+
+            if ($this->hasCommand($input)) {
+                $this->addHistory($input);
+                $this->runCommand($input);
+
+                continue;
+            }
+
+            $this->addCode($input);
+        } while (!$this->hasValidCode());
+    }
+
+    /**
+     * Run execution loop listeners before the shell session.
+     */
+    protected function beforeRun()
+    {
+        foreach ($this->loopListeners as $listener) {
+            $listener->beforeRun($this);
+        }
+    }
+
+    /**
+     * Run execution loop listeners at the start of each loop.
+     */
+    public function beforeLoop()
+    {
+        foreach ($this->loopListeners as $listener) {
+            $listener->beforeLoop($this);
+        }
+    }
+
+    /**
+     * Run execution loop listeners on user input.
+     *
+     * @param string $input
+     *
+     * @return string
+     */
+    public function onInput($input)
+    {
+        foreach ($this->loopListeners as $listeners) {
+            if (($return = $listeners->onInput($this, $input)) !== null) {
+                $input = $return;
+            }
+        }
+
+        return $input;
+    }
+
+    /**
+     * Run execution loop listeners on code to be executed.
+     *
+     * @param string $code
+     *
+     * @return string
+     */
+    public function onExecute($code)
+    {
+        foreach ($this->loopListeners as $listener) {
+            if (($return = $listener->onExecute($this, $code)) !== null) {
+                $code = $return;
+            }
+        }
+
+        return $code;
+    }
+
+    /**
+     * Run execution loop listeners after each loop.
+     */
+    public function afterLoop()
+    {
+        foreach ($this->loopListeners as $listener) {
+            $listener->afterLoop($this);
+        }
+    }
+
+    /**
+     * Run execution loop listers after the shell session.
+     */
+    protected function afterRun()
+    {
+        foreach ($this->loopListeners as $listener) {
+            $listener->afterRun($this);
+        }
+    }
+
+    /**
+     * Set the variables currently in scope.
+     *
+     * @param array $vars
+     */
+    public function setScopeVariables(array $vars)
+    {
+        $this->context->setAll($vars);
+    }
+
+    /**
+     * Return the set of variables currently in scope.
+     *
+     * @param bool $includeBoundObject Pass false to exclude 'this'. If you're
+     *                                 passing the scope variables to `extract`
+     *                                 in PHP 7.1+, you _must_ exclude 'this'
+     *
+     * @return array Associative array of scope variables
+     */
+    public function getScopeVariables($includeBoundObject = true)
+    {
+        $vars = $this->context->getAll();
+
+        if (!$includeBoundObject) {
+            unset($vars['this']);
+        }
+
+        return $vars;
+    }
+
+    /**
+     * Return the set of magic variables currently in scope.
+     *
+     * @param bool $includeBoundObject Pass false to exclude 'this'. If you're
+     *                                 passing the scope variables to `extract`
+     *                                 in PHP 7.1+, you _must_ exclude 'this'
+     *
+     * @return array Associative array of magic scope variables
+     */
+    public function getSpecialScopeVariables($includeBoundObject = true)
+    {
+        $vars = $this->context->getSpecialVariables();
+
+        if (!$includeBoundObject) {
+            unset($vars['this']);
+        }
+
+        return $vars;
+    }
+
+    /**
+     * Get the set of unused command-scope variable names.
+     *
+     * @return array Array of unused variable names
+     */
+    public function getUnusedCommandScopeVariableNames()
+    {
+        return $this->context->getUnusedCommandScopeVariableNames();
+    }
+
+    /**
+     * Get the set of variable names currently in scope.
+     *
+     * @return array Array of variable names
+     */
+    public function getScopeVariableNames()
+    {
+        return array_keys($this->context->getAll());
+    }
+
+    /**
+     * Get a scope variable value by name.
+     *
+     * @param string $name
+     *
+     * @return mixed
+     */
+    public function getScopeVariable($name)
+    {
+        return $this->context->get($name);
+    }
+
+    /**
+     * Set the bound object ($this variable) for the interactive shell.
+     *
+     * @param object|null $boundObject
+     */
+    public function setBoundObject($boundObject)
+    {
+        $this->context->setBoundObject($boundObject);
+    }
+
+    /**
+     * Get the bound object ($this variable) for the interactive shell.
+     *
+     * @return object|null
+     */
+    public function getBoundObject()
+    {
+        return $this->context->getBoundObject();
+    }
+
+    /**
+     * Add includes, to be parsed and executed before running the interactive shell.
+     *
+     * @param array $includes
+     */
+    public function setIncludes(array $includes = [])
+    {
+        $this->includes = $includes;
+    }
+
+    /**
+     * Get PHP files to be parsed and executed before running the interactive shell.
+     *
+     * @return array
+     */
+    public function getIncludes()
+    {
+        return array_merge($this->config->getDefaultIncludes(), $this->includes);
+    }
+
+    /**
+     * Check whether this shell's code buffer contains code.
+     *
+     * @return bool True if the code buffer contains code
+     */
+    public function hasCode()
+    {
+        return !empty($this->codeBuffer);
+    }
+
+    /**
+     * Check whether the code in this shell's code buffer is valid.
+     *
+     * If the code is valid, the code buffer should be flushed and evaluated.
+     *
+     * @return bool True if the code buffer content is valid
+     */
+    protected function hasValidCode()
+    {
+        return !$this->codeBufferOpen && $this->code !== false;
+    }
+
+    /**
+     * Add code to the code buffer.
+     *
+     * @param string $code
+     * @param bool   $silent
+     */
+    public function addCode($code, $silent = false)
+    {
+        try {
+            // Code lines ending in \ keep the buffer open
+            if (substr(rtrim($code), -1) === '\\') {
+                $this->codeBufferOpen = true;
+                $code = substr(rtrim($code), 0, -1);
+            } else {
+                $this->codeBufferOpen = false;
+            }
+
+            $this->codeBuffer[] = $silent ? new SilentInput($code) : $code;
+            $this->code         = $this->cleaner->clean($this->codeBuffer, $this->config->requireSemicolons());
+        } catch (\Exception $e) {
+            // Add failed code blocks to the readline history.
+            $this->addCodeBufferToHistory();
+
+            throw $e;
+        }
+    }
+
+    /**
+     * Set the code buffer.
+     *
+     * This is mostly used by `Shell::execute`. Any existing code in the input
+     * buffer is pushed onto a stack and will come back after this new code is
+     * executed.
+     *
+     * @throws \InvalidArgumentException if $code isn't a complete statement
+     *
+     * @param string $code
+     * @param bool   $silent
+     */
+    private function setCode($code, $silent = false)
+    {
+        if ($this->hasCode()) {
+            $this->codeStack[] = [$this->codeBuffer, $this->codeBufferOpen, $this->code];
+        }
+
+        $this->resetCodeBuffer();
+        try {
+            $this->addCode($code, $silent);
+        } catch (\Throwable $e) {
+            $this->popCodeStack();
+
+            throw $e;
+        } catch (\Exception $e) {
+            $this->popCodeStack();
+
+            throw $e;
+        }
+
+        if (!$this->hasValidCode()) {
+            $this->popCodeStack();
+
+            throw new \InvalidArgumentException('Unexpected end of input');
+        }
+    }
+
+    /**
+     * Get the current code buffer.
+     *
+     * This is useful for commands which manipulate the buffer.
+     *
+     * @return array
+     */
+    public function getCodeBuffer()
+    {
+        return $this->codeBuffer;
+    }
+
+    /**
+     * Run a Psy Shell command given the user input.
+     *
+     * @throws InvalidArgumentException if the input is not a valid command
+     *
+     * @param string $input User input string
+     *
+     * @return mixed Who knows?
+     */
+    protected function runCommand($input)
+    {
+        $command = $this->getCommand($input);
+
+        if (empty($command)) {
+            throw new \InvalidArgumentException('Command not found: ' . $input);
+        }
+
+        $input = new ShellInput(str_replace('\\', '\\\\', rtrim($input, " \t\n\r\0\x0B;")));
+
+        if ($input->hasParameterOption(['--help', '-h'])) {
+            $helpCommand = $this->get('help');
+            $helpCommand->setCommand($command);
+
+            return $helpCommand->run($input, $this->output);
+        }
+
+        return $command->run($input, $this->output);
+    }
+
+    /**
+     * Reset the current code buffer.
+     *
+     * This should be run after evaluating user input, catching exceptions, or
+     * on demand by commands such as BufferCommand.
+     */
+    public function resetCodeBuffer()
+    {
+        $this->codeBuffer = [];
+        $this->code       = false;
+    }
+
+    /**
+     * Inject input into the input buffer.
+     *
+     * This is useful for commands which want to replay history.
+     *
+     * @param string|array $input
+     * @param bool         $silent
+     */
+    public function addInput($input, $silent = false)
+    {
+        foreach ((array) $input as $line) {
+            $this->inputBuffer[] = $silent ? new SilentInput($line) : $line;
+        }
+    }
+
+    /**
+     * Flush the current (valid) code buffer.
+     *
+     * If the code buffer is valid, resets the code buffer and returns the
+     * current code.
+     *
+     * @return string PHP code buffer contents
+     */
+    public function flushCode()
+    {
+        if ($this->hasValidCode()) {
+            $this->addCodeBufferToHistory();
+            $code = $this->code;
+            $this->popCodeStack();
+
+            return $code;
+        }
+    }
+
+    /**
+     * Reset the code buffer and restore any code pushed during `execute` calls.
+     */
+    private function popCodeStack()
+    {
+        $this->resetCodeBuffer();
+
+        if (empty($this->codeStack)) {
+            return;
+        }
+
+        list($codeBuffer, $codeBufferOpen, $code) = array_pop($this->codeStack);
+
+        $this->codeBuffer     = $codeBuffer;
+        $this->codeBufferOpen = $codeBufferOpen;
+        $this->code           = $code;
+    }
+
+    /**
+     * (Possibly) add a line to the readline history.
+     *
+     * Like Bash, if the line starts with a space character, it will be omitted
+     * from history. Note that an entire block multi-line code input will be
+     * omitted iff the first line begins with a space.
+     *
+     * Additionally, if a line is "silent", i.e. it was initially added with the
+     * silent flag, it will also be omitted.
+     *
+     * @param string|SilentInput $line
+     */
+    private function addHistory($line)
+    {
+        if ($line instanceof SilentInput) {
+            return;
+        }
+
+        // Skip empty lines and lines starting with a space
+        if (trim($line) !== '' && substr($line, 0, 1) !== ' ') {
+            $this->readline->addHistory($line);
+        }
+    }
+
+    /**
+     * Filter silent input from code buffer, write the rest to readline history.
+     */
+    private function addCodeBufferToHistory()
+    {
+        $codeBuffer = array_filter($this->codeBuffer, function ($line) {
+            return !$line instanceof SilentInput;
+        });
+
+        $this->addHistory(implode("\n", $codeBuffer));
+    }
+
+    /**
+     * Get the current evaluation scope namespace.
+     *
+     * @see CodeCleaner::getNamespace
+     *
+     * @return string Current code namespace
+     */
+    public function getNamespace()
+    {
+        if ($namespace = $this->cleaner->getNamespace()) {
+            return implode('\\', $namespace);
+        }
+    }
+
+    /**
+     * Write a string to stdout.
+     *
+     * This is used by the shell loop for rendering output from evaluated code.
+     *
+     * @param string $out
+     * @param int    $phase Output buffering phase
+     */
+    public function writeStdout($out, $phase = PHP_OUTPUT_HANDLER_END)
+    {
+        $isCleaning = $phase & PHP_OUTPUT_HANDLER_CLEAN;
+
+        // Incremental flush
+        if ($out !== '' && !$isCleaning) {
+            $this->output->write($out, false, ShellOutput::OUTPUT_RAW);
+            $this->outputWantsNewline = (substr($out, -1) !== "\n");
+            $this->stdoutBuffer .= $out;
+        }
+
+        // Output buffering is done!
+        if ($phase & PHP_OUTPUT_HANDLER_END) {
+            // Write an extra newline if stdout didn't end with one
+            if ($this->outputWantsNewline) {
+                $this->output->writeln(sprintf('<aside>%s</aside>', $this->config->useUnicode() ? '⏎' : '\\n'));
+                $this->outputWantsNewline = false;
+            }
+
+            // Save the stdout buffer as $__out
+            if ($this->stdoutBuffer !== '') {
+                $this->context->setLastStdout($this->stdoutBuffer);
+                $this->stdoutBuffer = '';
+            }
+        }
+    }
+
+    /**
+     * Write a return value to stdout.
+     *
+     * The return value is formatted or pretty-printed, and rendered in a
+     * visibly distinct manner (in this case, as cyan).
+     *
+     * @see self::presentValue
+     *
+     * @param mixed $ret
+     */
+    public function writeReturnValue($ret)
+    {
+        if ($ret instanceof NoReturnValue) {
+            return;
+        }
+
+        $this->context->setReturnValue($ret);
+        $ret    = $this->presentValue($ret);
+        $indent = str_repeat(' ', strlen(static::RETVAL));
+
+        $this->output->writeln(static::RETVAL . str_replace(PHP_EOL, PHP_EOL . $indent, $ret));
+    }
+
+    /**
+     * Renders a caught Exception.
+     *
+     * Exceptions are formatted according to severity. ErrorExceptions which were
+     * warnings or Strict errors aren't rendered as harshly as real errors.
+     *
+     * Stores $e as the last Exception in the Shell Context.
+     *
+     * @param \Exception $e An exception instance
+     */
+    public function writeException(\Exception $e)
+    {
+        $this->context->setLastException($e);
+        $this->output->writeln($this->formatException($e));
+        $this->resetCodeBuffer();
+    }
+
+    /**
+     * Helper for formatting an exception for writeException().
+     *
+     * @todo extract this to somewhere it makes more sense
+     *
+     * @param \Exception $e
+     *
+     * @return string
+     */
+    public function formatException(\Exception $e)
+    {
+        $message = $e->getMessage();
+        if (!$e instanceof PsyException) {
+            if ($message === '') {
+                $message = get_class($e);
+            } else {
+                $message = sprintf('%s with message \'%s\'', get_class($e), $message);
+            }
+        }
+
+        $message = preg_replace(
+            "#(\\w:)?(/\\w+)*/src/ExecutionClosure.php\(\d+\) : eval\(\)'d code#",
+            "eval()'d code",
+            str_replace('\\', '/', $message)
+        );
+
+        $message = str_replace(" in eval()'d code", ' in Psy Shell code', $message);
+
+        $severity = ($e instanceof \ErrorException) ? $this->getSeverity($e) : 'error';
+
+        return sprintf('<%s>%s</%s>', $severity, OutputFormatter::escape($message), $severity);
+    }
+
+    /**
+     * Helper for getting an output style for the given ErrorException's level.
+     *
+     * @param \ErrorException $e
+     *
+     * @return string
+     */
+    protected function getSeverity(\ErrorException $e)
+    {
+        $severity = $e->getSeverity();
+        if ($severity & error_reporting()) {
+            switch ($severity) {
+                case E_WARNING:
+                case E_NOTICE:
+                case E_CORE_WARNING:
+                case E_COMPILE_WARNING:
+                case E_USER_WARNING:
+                case E_USER_NOTICE:
+                case E_STRICT:
+                    return 'warning';
+
+                default:
+                    return 'error';
+            }
+        } else {
+            // Since this is below the user's reporting threshold, it's always going to be a warning.
+            return 'warning';
+        }
+    }
+
+    /**
+     * Execute code in the shell execution context.
+     *
+     * @param string $code
+     * @param bool   $throwExceptions
+     *
+     * @return mixed
+     */
+    public function execute($code, $throwExceptions = false)
+    {
+        $this->setCode($code, true);
+        $closure = new ExecutionClosure($this);
+
+        if ($throwExceptions) {
+            return $closure->execute();
+        }
+
+        try {
+            return $closure->execute();
+        } catch (\TypeError $_e) {
+            $this->writeException(TypeErrorException::fromTypeError($_e));
+        } catch (\Error $_e) {
+            $this->writeException(ErrorException::fromError($_e));
+        } catch (\Exception $_e) {
+            $this->writeException($_e);
+        }
+    }
+
+    /**
+     * Helper for throwing an ErrorException.
+     *
+     * This allows us to:
+     *
+     *     set_error_handler(array($psysh, 'handleError'));
+     *
+     * Unlike ErrorException::throwException, this error handler respects the
+     * current error_reporting level; i.e. it logs warnings and notices, but
+     * doesn't throw an exception unless it's above the current error_reporting
+     * threshold. This should probably only be used in the inner execution loop
+     * of the shell, as most of the time a thrown exception is much more useful.
+     *
+     * If the error type matches the `errorLoggingLevel` config, it will be
+     * logged as well, regardless of the `error_reporting` level.
+     *
+     * @see \Psy\Exception\ErrorException::throwException
+     * @see \Psy\Shell::writeException
+     *
+     * @throws \Psy\Exception\ErrorException depending on the current error_reporting level
+     *
+     * @param int    $errno   Error type
+     * @param string $errstr  Message
+     * @param string $errfile Filename
+     * @param int    $errline Line number
+     */
+    public function handleError($errno, $errstr, $errfile, $errline)
+    {
+        if ($errno & error_reporting()) {
+            ErrorException::throwException($errno, $errstr, $errfile, $errline);
+        } elseif ($errno & $this->config->errorLoggingLevel()) {
+            // log it and continue...
+            $this->writeException(new ErrorException($errstr, 0, $errno, $errfile, $errline));
+        }
+    }
+
+    /**
+     * Format a value for display.
+     *
+     * @see Presenter::present
+     *
+     * @param mixed $val
+     *
+     * @return string Formatted value
+     */
+    protected function presentValue($val)
+    {
+        return $this->config->getPresenter()->present($val);
+    }
+
+    /**
+     * Get a command (if one exists) for the current input string.
+     *
+     * @param string $input
+     *
+     * @return null|BaseCommand
+     */
+    protected function getCommand($input)
+    {
+        $input = new StringInput($input);
+        if ($name = $input->getFirstArgument()) {
+            return $this->get($name);
+        }
+    }
+
+    /**
+     * Check whether a command is set for the current input string.
+     *
+     * @param string $input
+     *
+     * @return bool True if the shell has a command for the given input
+     */
+    protected function hasCommand($input)
+    {
+        $input = new StringInput($input);
+        if ($name = $input->getFirstArgument()) {
+            return $this->has($name);
+        }
+
+        return false;
+    }
+
+    /**
+     * Get the current input prompt.
+     *
+     * @return string
+     */
+    protected function getPrompt()
+    {
+        if ($this->hasCode()) {
+            return static::BUFF_PROMPT;
+        }
+
+        return $this->config->getPrompt() ?: static::PROMPT;
+    }
+
+    /**
+     * Read a line of user input.
+     *
+     * This will return a line from the input buffer (if any exist). Otherwise,
+     * it will ask the user for input.
+     *
+     * If readline is enabled, this delegates to readline. Otherwise, it's an
+     * ugly `fgets` call.
+     *
+     * @return string One line of user input
+     */
+    protected function readline()
+    {
+        if (!empty($this->inputBuffer)) {
+            $line = array_shift($this->inputBuffer);
+            if (!$line instanceof SilentInput) {
+                $this->output->writeln(sprintf('<aside>%s %s</aside>', static::REPLAY, OutputFormatter::escape($line)));
+            }
+
+            return $line;
+        }
+
+        if ($bracketedPaste = $this->config->useBracketedPaste()) {
+            printf("\e[?2004h"); // Enable bracketed paste
+        }
+
+        $line = $this->readline->readline($this->getPrompt());
+
+        if ($bracketedPaste) {
+            printf("\e[?2004l"); // ... and disable it again
+        }
+
+        return $line;
+    }
+
+    /**
+     * Get the shell output header.
+     *
+     * @return string
+     */
+    protected function getHeader()
+    {
+        return sprintf('<aside>%s by Justin Hileman</aside>', $this->getVersion());
+    }
+
+    /**
+     * Get the current version of Psy Shell.
+     *
+     * @return string
+     */
+    public function getVersion()
+    {
+        $separator = $this->config->useUnicode() ? '—' : '-';
+
+        return sprintf('Psy Shell %s (PHP %s %s %s)', self::VERSION, phpversion(), $separator, php_sapi_name());
+    }
+
+    /**
+     * Get a PHP manual database instance.
+     *
+     * @return \PDO|null
+     */
+    public function getManualDb()
+    {
+        return $this->config->getManualDb();
+    }
+
+    /**
+     * @deprecated Tab completion is provided by the AutoCompleter service
+     */
+    protected function autocomplete($text)
+    {
+        @trigger_error('Tab completion is provided by the AutoCompleter service', E_USER_DEPRECATED);
+    }
+
+    /**
+     * Initialize tab completion matchers.
+     *
+     * If tab completion is enabled this adds tab completion matchers to the
+     * auto completer and sets context if needed.
+     */
+    protected function initializeTabCompletion()
+    {
+        if (!$this->config->useTabCompletion()) {
+            return;
+        }
+
+        $this->autoCompleter = $this->config->getAutoCompleter();
+
+        // auto completer needs shell to be linked to configuration because of
+        // the context aware matchers
+        $this->addMatchersToAutoCompleter($this->getDefaultMatchers());
+        $this->addMatchersToAutoCompleter($this->matchers);
+
+        $this->autoCompleter->activate();
+    }
+
+    /**
+     * Add matchers to the auto completer, setting context if needed.
+     *
+     * @param array $matchers
+     */
+    private function addMatchersToAutoCompleter(array $matchers)
+    {
+        foreach ($matchers as $matcher) {
+            if ($matcher instanceof ContextAware) {
+                $matcher->setContext($this->context);
+            }
+            $this->autoCompleter->addMatcher($matcher);
+        }
+    }
+
+    /**
+     * @todo Implement self-update
+     * @todo Implement prompt to start update
+     *
+     * @return void|string
+     */
+    protected function writeVersionInfo()
+    {
+        if (PHP_SAPI !== 'cli') {
+            return;
+        }
+
+        try {
+            $client = $this->config->getChecker();
+            if (!$client->isLatest()) {
+                $this->output->writeln(sprintf('New version is available (current: %s, latest: %s)', self::VERSION, $client->getLatest()));
+            }
+        } catch (\InvalidArgumentException $e) {
+            $this->output->writeln($e->getMessage());
+        }
+    }
+
+    /**
+     * Write a startup message if set.
+     */
+    protected function writeStartupMessage()
+    {
+        $message = $this->config->getStartupMessage();
+        if ($message !== null && $message !== '') {
+            $this->output->writeln($message);
+        }
+    }
+}