/*

 * Copyright (c) 1997, 2017, 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_CLASSFILE_CLASSLOADER_HPP

#define SHARE_VM_CLASSFILE_CLASSLOADER_HPP

#include "runtime/orderAccess.hpp"

#include "runtime/perfData.hpp"

#include "utilities/exceptions.hpp"

#include "utilities/macros.hpp"

// The VM class loader.

#include <sys/stat.h>

// Name of boot "modules" image

#define  MODULES_IMAGE_NAME "modules"

// Class path entry (directory or zip file)

class JImageFile;

class ClassFileStream;

class PackageEntry;

class ClassPathEntry : public CHeapObj<mtClass> {

private:

  ClassPathEntry* volatile _next;

public:

  // Next entry in class path

  ClassPathEntry* next() const { return OrderAccess::load_acquire(&_next); }

  virtual ~ClassPathEntry() {}

  void set_next(ClassPathEntry* next) {

    // may have unlocked readers, so ensure visibility.

    OrderAccess::release_store(&_next, next);

  }

  virtual bool is_modules_image() const = 0;

  virtual bool is_jar_file() const = 0;

  virtual const char* name() const = 0;

  virtual JImageFile* jimage() const = 0;

  // Constructor

  ClassPathEntry() : _next(NULL) {}

  // 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, TRAPS) = 0;

  // Debugging

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

};

class ClassPathDirEntry: public ClassPathEntry {

 private:

  const char* _dir;           // Name of directory

 public:

  bool is_modules_image() const { return false; }

  bool is_jar_file() const { return false;  }

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

  JImageFile* jimage() const { return NULL; }

  ClassPathDirEntry(const char* dir);

  virtual ~ClassPathDirEntry() {}

  ClassFileStream* open_stream(const char* name, TRAPS);

  // Debugging

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

};

// 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 {

 enum {

   _unknown = 0,

   _yes     = 1,

   _no      = 2

 };

 private:

  jzfile* _zip;              // The zip archive

  const char*   _zip_name;   // Name of zip archive

  bool _is_boot_append;      // entry coming from -Xbootclasspath/a

  u1 _multi_versioned;       // indicates if the jar file has multi-versioned entries.

                             // It can have value of "_unknown", "_yes", or "_no"

 public:

  bool is_modules_image() const { return false; }

  bool is_jar_file() const { return true;  }

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

  JImageFile* jimage() const { return NULL; }

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

  virtual ~ClassPathZipEntry();

  u1* open_entry(const char* name, jint* filesize, bool nul_terminate, TRAPS);

  u1* open_versioned_entry(const char* name, jint* filesize, TRAPS) NOT_CDS_RETURN_(NULL);

  ClassFileStream* open_stream(const char* name, TRAPS);

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

  bool is_multiple_versioned(TRAPS) NOT_CDS_RETURN_(false);

  // Debugging

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

};

// For java image files

class ClassPathImageEntry: public ClassPathEntry {

private:

  JImageFile* _jimage;

  const char* _name;

public:

  bool is_modules_image() const;

  bool is_jar_file() const { return false; }

  bool is_open() const { return _jimage != NULL; }

  const char* name() const { return _name == NULL ? "" : _name; }

  JImageFile* jimage() const { return _jimage; }

  ClassPathImageEntry(JImageFile* jimage, const char* name);

  virtual ~ClassPathImageEntry();

  ClassFileStream* open_stream(const char* name, TRAPS);

  // Debugging

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

};

// ModuleClassPathList contains a linked list of ClassPathEntry's

// that have been specified for a specific module.  Currently,

// the only way to specify a module/path pair is via the --patch-module

// command line option.

class ModuleClassPathList : public CHeapObj<mtClass> {

private:

  Symbol* _module_name;

  // First and last entries of class path entries for a specific module

  ClassPathEntry* _module_first_entry;

  ClassPathEntry* _module_last_entry;

public:

  Symbol* module_name() const { return _module_name; }

  ClassPathEntry* module_first_entry() const { return _module_first_entry; }

  ModuleClassPathList(Symbol* module_name);

  ~ModuleClassPathList();

  void add_to_list(ClassPathEntry* new_entry);

};

class SharedPathsMiscInfo;

class ClassLoader: AllStatic {

 public:

  enum ClassLoaderType {

    BOOT_LOADER = 1,      /* boot loader */

    PLATFORM_LOADER  = 2, /* PlatformClassLoader */

    APP_LOADER  = 3       /* AppClassLoader */

  };

 protected:

  // 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;

  // The boot class path consists of 3 ordered pieces:

  //  1. the module/path pairs specified to --patch-module

  //    --patch-module=<module>=<file>(<pathsep><file>)*

  //  2. the base piece

  //    [jimage | build with exploded modules]

  //  3. boot loader append path

  //    [-Xbootclasspath/a]; [jvmti appended entries]

  //

  // The boot loader must obey this order when attempting

  // to load a class.

  // 1. Contains the module/path pairs specified to --patch-module

  static GrowableArray<ModuleClassPathList*>* _patch_mod_entries;

  // 2. the base piece

  //    Contains the ClassPathEntry of the modular java runtime image.

  //    If no java runtime image is present, this indicates a

  //    build with exploded modules is being used instead.

  static ClassPathEntry* _jrt_entry;

  static GrowableArray<ModuleClassPathList*>* _exploded_entries;

  enum { EXPLODED_ENTRY_SIZE = 80 }; // Initial number of exploded modules

  // 3. the boot loader's append path

  //    [-Xbootclasspath/a]; [jvmti appended entries]

  //    Note: boot loader append path does not support named modules.

  static ClassPathEntry* _first_append_entry;

  // Last entry in linked list of appended ClassPathEntry instances

  static ClassPathEntry* _last_append_entry;

  // Array of module names associated with the boot class loader

  CDS_ONLY(static GrowableArray<char*>* _boot_modules_array;)

  // Array of module names associated with the platform class loader

  CDS_ONLY(static GrowableArray<char*>* _platform_modules_array;)

  // Info used by CDS

  CDS_ONLY(static SharedPathsMiscInfo * _shared_paths_misc_info;)

  CDS_ONLY(static ClassPathEntry* _app_classpath_entries;)

  CDS_ONLY(static ClassPathEntry* _last_app_classpath_entry;)

  CDS_ONLY(static void setup_app_search_path(const char *class_path);)

  static void add_to_app_classpath_entries(const char* path,

                                           ClassPathEntry* entry,

                                           bool check_for_duplicates);

 public:

  CDS_ONLY(static ClassPathEntry* app_classpath_entries() {return _app_classpath_entries;})

 protected:

  // Initialization:

  //   - setup the boot loader's system class path

  //   - setup the boot loader's patch mod entries, if present

  //   - create the ModuleEntry for java.base

  static void setup_bootstrap_search_path();

  static void setup_boot_search_path(const char *class_path);

  static void setup_patch_mod_entries();

  static void create_javabase();

  static void load_zip_library();

  static void load_jimage_library();

  static ClassPathEntry* create_class_path_entry(const char *path, const struct stat* st,

                                                 bool throw_exception,

                                                 bool is_boot_append, TRAPS);

 public:

  // If the package for the fully qualified class name is in the boot

  // loader's package entry table then add_package() sets the classpath_index

  // field so that get_system_package() will know to return a non-null value

  // for the package's location.  And, so that the package will be added to

  // the list of packages returned by get_system_packages().

  // For packages whose classes are loaded from the boot loader class path, the

  // classpath_index indicates which entry on the boot loader class path.

  static bool add_package(const char *fullq_class_name, s2 classpath_index, TRAPS);

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

  // to avoid confusing the zip library

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

  static const char* file_name_for_class_name(const char* class_name,

                                              int class_name_len);

  static PackageEntry* get_package_entry(const char* class_name, ClassLoaderData* loader_data, TRAPS);

 public:

  static jboolean decompress(void *in, u8 inSize, void *out, u8 outSize, char **pmsg);

  static int crc32(int crc, const char* buf, int len);

  static bool update_class_path_entry_list(const char *path,

                                           bool check_for_duplicates,

                                           bool is_boot_append,

                                           bool throw_exception=true);

  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;

  }

  // Modular java runtime image is present vs. a build with exploded modules

  static bool has_jrt_entry() { return (_jrt_entry != NULL); }

  static ClassPathEntry* get_jrt_entry() { return _jrt_entry; }

  // Add a module's exploded directory to the boot loader's exploded module build list

  static void add_to_exploded_build_list(Symbol* module_name, TRAPS);

  // Attempt load of individual class from either the patched or exploded modules build lists

  static ClassFileStream* search_module_entries(const GrowableArray<ModuleClassPathList*>* const module_list,

                                                const char* const class_name,

                                                const char* const file_name, TRAPS);

  // Load individual .class file

  static InstanceKlass* load_class(Symbol* class_name, bool search_append_only, 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 classLoader_init2(TRAPS);

  CDS_ONLY(static void initialize_shared_path();)

  static int compute_Object_vtable();

  static ClassPathEntry* classpath_entry(int n) {

    assert(n >= 0, "sanity");

    if (n == 0) {

      assert(has_jrt_entry(), "No class path entry at 0 for exploded module builds");

      return ClassLoader::_jrt_entry;

    } else {

      // The java runtime image is always the first entry

      // in the FileMapInfo::_classpath_entry_table. Even though

      // the _jrt_entry is not included in the _first_append_entry

      // linked list, it must be accounted for when comparing the

      // class path vs. the shared archive class path.

      ClassPathEntry* e = ClassLoader::_first_append_entry;

      while (--n >= 1) {

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

        e = e->next();

      }

      return e;

    }

  }

  static bool is_in_patch_mod_entries(Symbol* module_name);

#if INCLUDE_CDS

  // Sharing dump and restore

  // Helper function used by CDS code to get the number of boot classpath

  // entries during shared classpath setup time.

  static int num_boot_classpath_entries() {

    assert(DumpSharedSpaces, "Should only be called at CDS dump time");

    assert(has_jrt_entry(), "must have a java runtime image");

    int num_entries = 1; // count the runtime image

    ClassPathEntry* e = ClassLoader::_first_append_entry;

    while (e != NULL) {

      num_entries ++;

      e = e->next();

    }

    return num_entries;

  }

  static ClassPathEntry* get_next_boot_classpath_entry(ClassPathEntry* e) {

    if (e == ClassLoader::_jrt_entry) {

      return ClassLoader::_first_append_entry;

    } else {

      return e->next();

    }

  }

  // Helper function used by CDS code to get the number of app classpath

  // entries during shared classpath setup time.

  static int num_app_classpath_entries() {

    assert(DumpSharedSpaces, "Should only be called at CDS dump time");

    int num_entries = 0;

    ClassPathEntry* e= ClassLoader::_app_classpath_entries;

    while (e != NULL) {

      num_entries ++;

      e = e->next();

    }

    return num_entries;

  }

  static void  check_shared_classpath(const char *path);

  static void  finalize_shared_paths_misc_info();

  static int   get_shared_paths_misc_info_size();

  static void* get_shared_paths_misc_info();

  static bool  check_shared_paths_misc_info(void* info, int size);

  static void  exit_with_path_failure(const char* error, const char* message);

  static void record_result(InstanceKlass* ik, const ClassFileStream* stream);

#endif

  static JImageLocationRef jimage_find_resource(JImageFile* jf, const char* module_name,

                                                const char* file_name, jlong &size);

  static void  trace_class_path(const char* msg, const char* name = NULL);

  // 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_append_entry(const char* name);

  // adds a class path to the boot append entries

  static void add_to_boot_append_entries(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, bool is_boot_append);

  static bool string_ends_with(const char* str, const char* str_to_find);

  // obtain package name from a fully qualified class name

  // *bad_class_name is set to true if there's a problem with parsing class_name, to

  // distinguish from a class_name with no package name, as both cases have a NULL return value

  static const char* package_from_name(const char* const class_name, bool* bad_class_name = NULL);