/*

 * 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.

 *

 *

 */

// The VM class loader.

#include <sys/stat.h>

// Meta-index (optional, to be able to skip opening boot classpath jar files)

class MetaIndex: public CHeapObj {

 private:

  char** _meta_package_names;

  int    _num_meta_package_names;

 public:

  MetaIndex(char** meta_package_names, int num_meta_package_names);

  ~MetaIndex();

  bool may_contain(const char* class_name);

};

// Class path entry (directory or zip file)

class ClassPathEntry: public CHeapObj {

 private:

  ClassPathEntry* _next;

 public:

  // Next entry in class path

  ClassPathEntry* next()              { return _next; }

  void set_next(ClassPathEntry* next) {

    // may have unlocked readers, so write atomically.

    OrderAccess::release_store_ptr(&_next, next);

  }

  virtual bool is_jar_file() = 0;

  virtual const char* name() = 0;

  virtual bool is_lazy();

  // Constructor

  ClassPathEntry();

  // Attempt to locate file_name through this class path entry.

  // Returns a class file parsing stream if successfull.

  virtual ClassFileStream* open_stream(const char* name) = 0;

  // Debugging

  NOT_PRODUCT(virtual void compile_the_world(Handle loader, TRAPS) = 0;)

  NOT_PRODUCT(virtual bool is_rt_jar() = 0;)

};

class ClassPathDirEntry: public ClassPathEntry {

 private:

  char* _dir;           // Name of directory

 public:

  bool is_jar_file()  { return false;  }

  const char* name()  { return _dir; }

  ClassPathDirEntry(char* dir);

  ClassFileStream* open_stream(const char* name);

  // Debugging

  NOT_PRODUCT(void compile_the_world(Handle loader, TRAPS);)

  NOT_PRODUCT(bool is_rt_jar();)

};

// Type definitions for zip file and zip file entry

typedef void* jzfile;

typedef struct {

  char *name;                   /* entry name */

  jlong time;                   /* modification time */

  jlong size;                   /* size of uncompressed data */

  jlong csize;                  /* size of compressed data (zero if uncompressed) */

  jint crc;                     /* crc of uncompressed data */

  char *comment;                /* optional zip file comment */

  jbyte *extra;                 /* optional extra data */

  jlong pos;                    /* position of LOC header (if negative) or data */

} jzentry;

class ClassPathZipEntry: public ClassPathEntry {

 private:

  jzfile* _zip;        // The zip archive

  char*   _zip_name;   // Name of zip archive

 public:

  bool is_jar_file()  { return true;  }

  const char* name()  { return _zip_name; }

  ClassPathZipEntry(jzfile* zip, const char* zip_name);

  ~ClassPathZipEntry();

  ClassFileStream* open_stream(const char* name);

  void contents_do(void f(const char* name, void* context), void* context);

  // Debugging

  NOT_PRODUCT(void compile_the_world(Handle loader, TRAPS);)

  NOT_PRODUCT(void compile_the_world12(Handle loader, TRAPS);) // JDK 1.2 version

  NOT_PRODUCT(void compile_the_world13(Handle loader, TRAPS);) // JDK 1.3 version

  NOT_PRODUCT(bool is_rt_jar();)

  NOT_PRODUCT(bool is_rt_jar12();)

  NOT_PRODUCT(bool is_rt_jar13();)

};

// For lazier loading of boot class path entries

class LazyClassPathEntry: public ClassPathEntry {

 private:

  char* _path; // dir or file

  struct stat _st;

  MetaIndex* _meta_index;

  volatile ClassPathEntry* _resolved_entry;

  ClassPathEntry* resolve_entry();

 public:

  bool is_jar_file();

  const char* name()  { return _path; }

  LazyClassPathEntry(char* path, struct stat st);

  ClassFileStream* open_stream(const char* name);

  void set_meta_index(MetaIndex* meta_index) { _meta_index = meta_index; }

  virtual bool is_lazy();

  // Debugging

  NOT_PRODUCT(void compile_the_world(Handle loader, TRAPS);)

  NOT_PRODUCT(bool is_rt_jar();)

};

class PackageHashtable;

class PackageInfo;

class HashtableBucket;

class ClassLoader: AllStatic {

 public:

  enum SomeConstants {

    package_hash_table_size = 31  // Number of buckets

  };

 private:

  friend class LazyClassPathEntry;

  // Performance counters

  static PerfCounter* _perf_accumulated_time;

  static PerfCounter* _perf_classes_inited;

  static PerfCounter* _perf_class_init_time;

  static PerfCounter* _perf_class_init_selftime;

  static PerfCounter* _perf_classes_verified;

  static PerfCounter* _perf_class_verify_time;

  static PerfCounter* _perf_class_verify_selftime;

  static PerfCounter* _perf_classes_linked;

  static PerfCounter* _perf_class_link_time;

  static PerfCounter* _perf_class_link_selftime;

  static PerfCounter* _perf_class_parse_time;

  static PerfCounter* _perf_class_parse_selftime;

  static PerfCounter* _perf_sys_class_lookup_time;

  static PerfCounter* _perf_shared_classload_time;

  static PerfCounter* _perf_sys_classload_time;

  static PerfCounter* _perf_app_classload_time;

  static PerfCounter* _perf_app_classload_selftime;

  static PerfCounter* _perf_app_classload_count;

  static PerfCounter* _perf_define_appclasses;

  static PerfCounter* _perf_define_appclass_time;

  static PerfCounter* _perf_define_appclass_selftime;

  static PerfCounter* _perf_app_classfile_bytes_read;

  static PerfCounter* _perf_sys_classfile_bytes_read;

  static PerfCounter* _sync_systemLoaderLockContentionRate;

  static PerfCounter* _sync_nonSystemLoaderLockContentionRate;

  static PerfCounter* _sync_JVMFindLoadedClassLockFreeCounter;

  static PerfCounter* _sync_JVMDefineClassLockFreeCounter;

  static PerfCounter* _sync_JNIDefineClassLockFreeCounter;

  static PerfCounter* _unsafe_defineClassCallCounter;

  static PerfCounter* _isUnsyncloadClass;

  static PerfCounter* _load_instance_class_failCounter;

  // First entry in linked list of ClassPathEntry instances

  static ClassPathEntry* _first_entry;

  // Last entry in linked list of ClassPathEntry instances

  static ClassPathEntry* _last_entry;

  // Hash table used to keep track of loaded packages

  static PackageHashtable* _package_hash_table;

  static const char* _shared_archive;

  // Hash function

  static unsigned int hash(const char *s, int n);

  // Returns the package file name corresponding to the specified package

  // or class name, or null if not found.

  static PackageInfo* lookup_package(const char *pkgname);

  // Adds a new package entry for the specified class or package name and

  // corresponding directory or jar file name.

  static bool add_package(const char *pkgname, int classpath_index, TRAPS);

  // Initialization

  static void setup_meta_index();

  static void setup_bootstrap_search_path();

  static void load_zip_library();

  static void create_class_path_entry(char *path, struct stat st, ClassPathEntry **new_entry, bool lazy);

  // Canonicalizes path names, so strcmp will work properly. This is mainly

  // to avoid confusing the zip library

  static bool get_canonical_path(char* orig, char* out, int len);

 public:

  // Used by the kernel jvm.

  static void update_class_path_entry_list(const char *path,

                                           bool check_for_duplicates);

  static void print_bootclasspath();

  // Timing

  static PerfCounter* perf_accumulated_time()         { return _perf_accumulated_time; }

  static PerfCounter* perf_classes_inited()           { return _perf_classes_inited; }

  static PerfCounter* perf_class_init_time()          { return _perf_class_init_time; }

  static PerfCounter* perf_class_init_selftime()      { return _perf_class_init_selftime; }

  static PerfCounter* perf_classes_verified()         { return _perf_classes_verified; }

  static PerfCounter* perf_class_verify_time()        { return _perf_class_verify_time; }

  static PerfCounter* perf_class_verify_selftime()    { return _perf_class_verify_selftime; }

  static PerfCounter* perf_classes_linked()           { return _perf_classes_linked; }

  static PerfCounter* perf_class_link_time()          { return _perf_class_link_time; }

  static PerfCounter* perf_class_link_selftime()      { return _perf_class_link_selftime; }

  static PerfCounter* perf_class_parse_time()         { return _perf_class_parse_time; }

  static PerfCounter* perf_class_parse_selftime()     { return _perf_class_parse_selftime; }

  static PerfCounter* perf_sys_class_lookup_time()    { return _perf_sys_class_lookup_time; }

  static PerfCounter* perf_shared_classload_time()    { return _perf_shared_classload_time; }

  static PerfCounter* perf_sys_classload_time()       { return _perf_sys_classload_time; }

  static PerfCounter* perf_app_classload_time()       { return _perf_app_classload_time; }

  static PerfCounter* perf_app_classload_selftime()   { return _perf_app_classload_selftime; }

  static PerfCounter* perf_app_classload_count()      { return _perf_app_classload_count; }

  static PerfCounter* perf_define_appclasses()        { return _perf_define_appclasses; }

  static PerfCounter* perf_define_appclass_time()     { return _perf_define_appclass_time; }

  static PerfCounter* perf_define_appclass_selftime() { return _perf_define_appclass_selftime; }

  static PerfCounter* perf_app_classfile_bytes_read() { return _perf_app_classfile_bytes_read; }

  static PerfCounter* perf_sys_classfile_bytes_read() { return _perf_sys_classfile_bytes_read; }

  // Record how often system loader lock object is contended

  static PerfCounter* sync_systemLoaderLockContentionRate() {

    return _sync_systemLoaderLockContentionRate;

  }

  // Record how often non system loader lock object is contended

  static PerfCounter* sync_nonSystemLoaderLockContentionRate() {

    return _sync_nonSystemLoaderLockContentionRate;

  }

  // Record how many calls to JVM_FindLoadedClass w/o holding a lock

  static PerfCounter* sync_JVMFindLoadedClassLockFreeCounter() {

    return _sync_JVMFindLoadedClassLockFreeCounter;

  }

  // Record how many calls to JVM_DefineClass w/o holding a lock

  static PerfCounter* sync_JVMDefineClassLockFreeCounter() {

    return _sync_JVMDefineClassLockFreeCounter;

  }

  // Record how many calls to jni_DefineClass w/o holding a lock

  static PerfCounter* sync_JNIDefineClassLockFreeCounter() {

    return _sync_JNIDefineClassLockFreeCounter;

  }

  // Record how many calls to Unsafe_DefineClass

  static PerfCounter* unsafe_defineClassCallCounter() {

    return _unsafe_defineClassCallCounter;

  }

  // Record how many times SystemDictionary::load_instance_class call

  // fails with linkageError when Unsyncloadclass flag is set.

  static PerfCounter* load_instance_class_failCounter() {

    return _load_instance_class_failCounter;

  }

  // Load individual .class file

  static instanceKlassHandle load_classfile(symbolHandle h_name, TRAPS);

  // If the specified package has been loaded by the system, then returns

  // the name of the directory or ZIP file that the package was loaded from.

  // Returns null if the package was not loaded.

  // Note: The specified name can either be the name of a class or package.

  // If a package name is specified, then it must be "/"-separator and also

  // end with a trailing "/".

  static oop get_system_package(const char* name, TRAPS);

  // Returns an array of Java strings representing all of the currently

  // loaded system packages.

  // Note: The package names returned are "/"-separated and end with a

  // trailing "/".

  static objArrayOop get_system_packages(TRAPS);

  // Initialization

  static void initialize();

  static void create_package_info_table();

  static void create_package_info_table(HashtableBucket *t, int length,

                                        int number_of_entries);

  static int compute_Object_vtable();

  static ClassPathEntry* classpath_entry(int n) {

    ClassPathEntry* e = ClassLoader::_first_entry;

    while (--n >= 0) {

      assert(e != NULL, "Not that many classpath entries.");

      e = e->next();

    }

    return e;

  }

  // Sharing dump and restore

  static void copy_package_info_buckets(char** top, char* end);

  static void copy_package_info_table(char** top, char* end);

  // VM monitoring and management support

  static jlong classloader_time_ms();

  static jlong class_method_total_size();

  static jlong class_init_count();

  static jlong class_init_time_ms();

  static jlong class_verify_time_ms();

  static jlong class_link_count();

  static jlong class_link_time_ms();

  // indicates if class path already contains a entry (exact match by name)

  static bool contains_entry(ClassPathEntry* entry);

  // adds a class path list

  static void add_to_list(ClassPathEntry* new_entry);

  // creates a class path zip entry (returns NULL if JAR file cannot be opened)

  static ClassPathZipEntry* create_class_path_zip_entry(const char *apath);

  // Debugging

  static void verify()              PRODUCT_RETURN;

  // Force compilation of all methods in all classes in bootstrap class path (stress test)

#ifndef PRODUCT

 private:

  static int _compile_the_world_counter;

 public:

  static void compile_the_world();

  static void compile_the_world_in(char* name, Handle loader, TRAPS);

  static int  compile_the_world_counter() { return _compile_the_world_counter; }

#endif //PRODUCT

};

// PerfClassTraceTime is used to measure time for class loading related events.

// This class tracks cumulative time and exclusive time for specific event types.

// During the execution of one event, other event types (e.g. class loading and

// resolution) as well as recursive calls of the same event type could happen.

// Only one elapsed timer (cumulative) and one thread-local self timer (exclusive)

// (i.e. only one event type) are active at a time even multiple PerfClassTraceTime

// instances have been created as multiple events are happening.

class PerfClassTraceTime {

  public:

    enum {

       CLASS_LOAD   = 0,

       PARSE_CLASS  = 1,

       CLASS_LINK   = 2,

       CLASS_VERIFY = 3,

       CLASS_CLINIT = 4,

       DEFINE_CLASS = 5,

       EVENT_TYPE_COUNT = 6

    };

  protected:

    // _t tracks time from initialization to destruction of this timer instance

    // including time for all other event types, and recursive calls of this type.

    // When a timer is called recursively, the elapsedTimer _t would not be used.

    elapsedTimer     _t;

    PerfLongCounter* _timep;

    PerfLongCounter* _selftimep;

    PerfLongCounter* _eventp;

    // pointer to thread-local recursion counter and timer array

    // The thread_local timers track cumulative time for specific event types

    // exclusive of time for other event types, but including recursive calls

    // of the same type.

    int*             _recursion_counters;

    elapsedTimer*    _timers;

    int              _event_type;

    int              _prev_active_event;

  public:

    inline PerfClassTraceTime(PerfLongCounter* timep,     /* counter incremented with inclusive time */

                              PerfLongCounter* selftimep, /* counter incremented with exclusive time */

                              PerfLongCounter* eventp,    /* event counter */

                              int* recursion_counters,    /* thread-local recursion counter array */

                              elapsedTimer* timers,       /* thread-local timer array */

                              int type                    /* event type */ ) :

        _timep(timep), _selftimep(selftimep), _eventp(eventp), _recursion_counters(recursion_counters), _timers(timers), _event_type(type) {

      initialize();

    }

    inline PerfClassTraceTime(PerfLongCounter* timep,     /* counter incremented with inclusive time */

                              elapsedTimer* timers,       /* thread-local timer array */

                              int type                    /* event type */ ) :

        _timep(timep), _selftimep(NULL), _eventp(NULL), _recursion_counters(NULL), _timers(timers), _event_type(type) {

      initialize();

    }

    void initialize() {

      if (!UsePerfData) return;

      if (_eventp != NULL) {

        // increment the event counter

        _eventp->inc();

      }

      // stop the current active thread-local timer to measure inclusive time

      _prev_active_event = -1;

      for (int i=0; i < EVENT_TYPE_COUNT; i++) {

         if (_timers[i].is_active()) {

           assert(_prev_active_event == -1, "should have only one active timer");

           _prev_active_event = i;

           _timers[i].stop();

         }

      }

      if (_recursion_counters == NULL || (_recursion_counters[_event_type])++ == 0) {

        // start the inclusive timer if not recursively called

        _t.start();

      }

      // start thread-local timer of the given event type

      if (!_timers[_event_type].is_active()) {

        _timers[_event_type].start();

      }

    }

    inline void suspend() { _t.stop(); _timers[_event_type].stop(); }

    inline void resume()  { _t.start(); _timers[_event_type].start(); }

    ~PerfClassTraceTime() {

      if (!UsePerfData) return;

      // stop the thread-local timer as the event completes

      // and resume the thread-local timer of the event next on the stack

      _timers[_event_type].stop();

      jlong selftime = _timers[_event_type].ticks();

      if (_prev_active_event >= 0) {

        _timers[_prev_active_event].start();

      }

      if (_recursion_counters != NULL && --(_recursion_counters[_event_type]) > 0) return;

      // increment the counters only on the leaf call

      _t.stop();

      _timep->inc(_t.ticks());

      if (_selftimep != NULL) {

        _selftimep->inc(selftime);

      }

      // add all class loading related event selftime to the accumulated time counter

      ClassLoader::perf_accumulated_time()->inc(selftime);

      // reset the timer

      _timers[_event_type].reset();

    }

};