/*

 * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code 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 General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#ifndef SHARE_VM_SERVICES_DIAGNOSTICFRAMEWORK_HPP

#define SHARE_VM_SERVICES_DIAGNOSTICFRAMEWORK_HPP

#include "classfile/vmSymbols.hpp"

#include "memory/allocation.hpp"

#include "runtime/arguments.hpp"

#include "runtime/os.hpp"

#include "runtime/vm_version.hpp"

#include "runtime/vmThread.hpp"

#include "utilities/ostream.hpp"

// CmdLine is the class used to handle a command line containing a single

// diagnostic command and its arguments. It provides methods to access the

// command name and the beginning of the arguments. The class is also

// able to identify commented command lines and the "stop" keyword

class CmdLine : public StackObj {

private:

  const char* _cmd;

  size_t      _cmd_len;

  const char* _args;

  size_t      _args_len;

public:

  CmdLine(const char* line, size_t len, bool no_command_name);

  const char* args_addr() const { return _args; }

  size_t args_len() const { return _args_len; }

  const char* cmd_addr() const { return _cmd; }

  size_t cmd_len() const { return _cmd_len; }

  bool is_empty() { return _cmd_len == 0; }

  bool is_executable() { return is_empty() || _cmd[0] != '#'; }

  bool is_stop() { return !is_empty() && strncmp("stop", _cmd, _cmd_len) == 0; }

};

// Iterator class taking a character string in input and returning a CmdLine

// instance for each command line. The argument delimiter has to be specified.

class DCmdIter : public StackObj {

  friend class DCmd;

private:

  const char* _str;

  char        _delim;

  size_t      _len;

  size_t      _cursor;

public:

  DCmdIter(const char* str, char delim) {

    _str = str;

    _delim = delim;

    _len = strlen(str);

    _cursor = 0;

  }

  bool has_next() { return _cursor < _len; }

  CmdLine next() {

    assert(_cursor <= _len, "Cannot iterate more");

    size_t n = _cursor;

    while (n < _len && _str[n] != _delim) n++;

    CmdLine line(&(_str[_cursor]), n - _cursor, false);

    _cursor = n + 1;

    // The default copy constructor of CmdLine is used to return a CmdLine

    // instance to the caller.

    return line;

  }

};

// Iterator class to iterate over diagnostic command arguments

class DCmdArgIter : public ResourceObj {

  const char* _buffer;

  size_t      _len;

  size_t      _cursor;

  const char* _key_addr;

  size_t      _key_len;

  const char* _value_addr;

  size_t      _value_len;

  char        _delim;

public:

  DCmdArgIter(const char* buf, size_t len, char delim) {

    _buffer = buf;

    _len = len;

    _delim = delim;

    _cursor = 0;

  }

  bool next(TRAPS);

  const char* key_addr() { return _key_addr; }

  size_t key_length() { return _key_len; }

  const char* value_addr() { return _value_addr; }

  size_t value_length() { return _value_len; }

};

// A DCmdInfo instance provides a description of a diagnostic command. It is

// used to export the description to the JMX interface of the framework.

class DCmdInfo : public ResourceObj {

protected:

  const char* _name;

  const char* _description;

  const char* _impact;

  int         _num_arguments;

  bool        _is_enabled;

public:

  DCmdInfo(const char* name,

          const char* description,

          const char* impact,

          int num_arguments,

          bool enabled) {

    this->_name = name;

    this->_description = description;

    this->_impact = impact;

    this->_num_arguments = num_arguments;

    this->_is_enabled = enabled;

  }

  const char* name() const { return _name; }

  const char* description() const { return _description; }

  const char* impact() const { return _impact; }

  int num_arguments() const { return _num_arguments; }

  bool is_enabled() const { return _is_enabled; }

  static bool by_name(void* name, DCmdInfo* info);

};

// A DCmdArgumentInfo instance provides a description of a diagnostic command

// argument. It is used to export the description to the JMX interface of the

// framework.

class DCmdArgumentInfo : public ResourceObj {

protected:

  const char* _name;

  const char* _description;

  const char* _type;

  const char* _default_string;

  bool        _mandatory;

  bool        _option;

  int         _position;

public:

  DCmdArgumentInfo(const char* name, const char* description, const char* type,

                   const char* default_string, bool mandatory, bool option) {

    this->_name = name;

    this->_description = description;

    this->_type = type;

    this->_default_string = default_string;

    this->_option = option;

    this->_mandatory = mandatory;

    this->_option = option;

    this->_position = -1;

  }

  DCmdArgumentInfo(const char* name, const char* description, const char* type,

                   const char* default_string, bool mandatory, bool option,

                   int position) {

    this->_name = name;

    this->_description = description;

    this->_type = type;

    this->_default_string = default_string;

    this->_option = option;

    this->_mandatory = mandatory;

    this->_option = option;

    this->_position = position;

  }

  const char* name() const { return _name; }

  const char* description() const { return _description; }

  const char* type() const { return _type; }

  const char* default_string() const { return _default_string; }

  bool is_mandatory() const { return _mandatory; }

  bool is_option() const { return _option; }

  int position() const { return _position; }

};

// The DCmdParser class can be used to create an argument parser for a

// diagnostic command. It is not mandatory to use it to parse arguments.

class DCmdParser {

private:

  GenDCmdArgument* _options;

  GenDCmdArgument* _arguments_list;

  char             _delim;

public:

  DCmdParser() {

    _options = NULL;

    _arguments_list = NULL;

  }

  void add_dcmd_option(GenDCmdArgument* arg);

  void add_dcmd_argument(GenDCmdArgument* arg);

  GenDCmdArgument* lookup_dcmd_option(const char* name, size_t len);

  GenDCmdArgument* arguments_list() { return _arguments_list; };

  void check(TRAPS);

  void parse(CmdLine* line, char delim, TRAPS);

  void print_help(outputStream* out, const char* cmd_name);

  void reset(TRAPS);

  void cleanup();

  int num_arguments();

  GrowableArray<const char*>* argument_name_array();

  GrowableArray<DCmdArgumentInfo*>* argument_info_array();

};

// The DCmd class is the parent class of all diagnostic commands

// Diagnostic command instances should not be instantiated directly but

// created using the associated factory. The factory can be retrieved with

// the DCmdFactory::getFactory() method.

// A diagnostic command instance can either be allocated in the resource Area

// or in the C-heap. Allocation in the resource area is recommended when the

// current thread is the only one which will access the diagnostic command

// instance. Allocation in the C-heap is required when the diagnostic command

// is accessed by several threads (for instance to perform asynchronous

// execution).

// To ensure a proper cleanup, it's highly recommended to use a DCmdMark for

// each diagnostic command instance. In case of a C-heap allocated diagnostic

// command instance, the DCmdMark must be created in the context of the last

// thread that will access the instance.

class DCmd : public ResourceObj {

protected:

  outputStream* _output;

  bool          _is_heap_allocated;

public:

  DCmd(outputStream* output, bool heap_allocated) {

    _output = output;

    _is_heap_allocated = heap_allocated;

  }

  static const char* name() { return "No Name";}

  static const char* description() { return "No Help";}

  static const char* disabled_message() { return "Diagnostic command currently disabled"; }

  static const char* impact() { return "Low: No impact"; }

  static int num_arguments() { return 0; }

  outputStream* output() { return _output; }

  bool is_heap_allocated()  { return _is_heap_allocated; }

  virtual void print_help(outputStream* out) { };

  virtual void parse(CmdLine* line, char delim, TRAPS) { }

  virtual void execute(TRAPS) { }

  virtual void reset(TRAPS) { }

  virtual void cleanup() { }

  // support for the JMX interface

  virtual GrowableArray<const char*>* argument_name_array() {

    GrowableArray<const char*>* array = new GrowableArray<const char*>(0);

    return array;

  }

  virtual GrowableArray<DCmdArgumentInfo*>* argument_info_array() {

    GrowableArray<DCmdArgumentInfo*>* array = new GrowableArray<DCmdArgumentInfo*>(0);

    return array;

  }

  // main method to invoke the framework

  static void parse_and_execute(outputStream* out, const char* cmdline,

                                char delim, TRAPS);

};

class DCmdMark : public StackObj {

  DCmd* _ref;

public:

  DCmdMark(DCmd* cmd) { _ref = cmd; }

  ~DCmdMark() {

    if (_ref != NULL) {

      _ref->cleanup();

      if (_ref->is_heap_allocated()) {

        delete _ref;

      }

    }

  }

};

// Diagnostic commands are not directly instantiated but created with a factory.

// Each diagnostic command class has its own factory. The DCmdFactory class also

// manages the status of the diagnostic command (hidden, enabled). A DCmdFactory

// has to be registered to make the diagnostic command available (see

// management.cpp)

class DCmdFactory: public CHeapObj {

private:

  static Mutex*       _dcmdFactory_lock;

  // Pointer to the next factory in the singly-linked list of registered

  // diagnostic commands

  DCmdFactory*        _next;

  // When disabled, a diagnostic command cannot be executed. Any attempt to

  // execute it will result in the printing of the disabled message without

  // instantiating the command.

  bool                _enabled;

  // When hidden, a diagnostic command doesn't appear in the list of commands

  // provided by the 'help' command.

  bool                _hidden;

  int                 _num_arguments;

  static DCmdFactory* _DCmdFactoryList;

public:

  DCmdFactory(int num_arguments, bool enabled, bool hidden) {

    _next = NULL;

    _enabled = enabled;

    _hidden = hidden;

    _num_arguments = num_arguments;

  }

  bool is_enabled() const { return _enabled; }

  void set_enabled(bool b) { _enabled = b; }

  bool is_hidden() const { return _hidden; }

  void set_hidden(bool b) { _hidden = b; }

  int num_arguments() { return _num_arguments; }

  DCmdFactory* next() { return _next; }

  virtual DCmd* create_Cheap_instance(outputStream* output) = 0;

  virtual DCmd* create_resource_instance(outputStream* output) = 0;

  virtual const char* name() const = 0;

  virtual const char* description() const = 0;

  virtual const char* impact() const = 0;

  virtual const char* disabled_message() const = 0;

  // Register a DCmdFactory to make a diagnostic command available.

  // Once registered, a diagnostic command must not be unregistered.

  // To prevent a diagnostic command from being executed, just set the

  // enabled flag to false.

  static int register_DCmdFactory(DCmdFactory* factory);

  static DCmdFactory* factory(const char* cmd, size_t len);

  // Returns a C-heap allocated diagnostic command for the given command line

  static DCmd* create_global_DCmd(CmdLine &line, outputStream* out, TRAPS);

  // Returns a resourceArea allocated diagnostic command for the given command line

  static DCmd* create_local_DCmd(CmdLine &line, outputStream* out, TRAPS);

  static GrowableArray<const char*>* DCmd_list();

  static GrowableArray<DCmdInfo*>* DCmdInfo_list();

  friend class HelpDCmd;

};

// Template to easily create DCmdFactory instances. See management.cpp

// where this template is used to create and register factories.

template <class DCmdClass> class DCmdFactoryImpl : public DCmdFactory {

public:

  DCmdFactoryImpl(bool enabled, bool hidden) :

    DCmdFactory(DCmdClass::num_arguments(), enabled, hidden) { }

  // Returns a C-heap allocated instance

  virtual DCmd* create_Cheap_instance(outputStream* output) {

    return new (ResourceObj::C_HEAP) DCmdClass(output, true);

  }

  // Returns a resourceArea allocated instance

  virtual DCmd* create_resource_instance(outputStream* output) {

    return new DCmdClass(output, false);

  }

  virtual const char* name() const {

    return DCmdClass::name();

  }

  virtual const char* description() const {

    return DCmdClass::description();

  }

  virtual const char* impact() const {

    return DCmdClass::impact();

  }

  virtual const char* disabled_message() const {

     return DCmdClass::disabled_message();

  }

};

#endif // SHARE_VM_SERVICES_DIAGNOSTICFRAMEWORK_HPP