/*

 * Copyright 1997-2007 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 *

 */

// 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_verify_time;

  static PerfCounter* _perf_classes_linked;

  static PerfCounter* _perf_class_link_time;

  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

  // 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

};