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hotspot/src/share/vm/classfile/classLoader.hpp

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+/*
+ * 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
+  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_verify_time() { return _perf_class_verify_time; }
+  static PerfCounter* perf_classes_linked()    { return _perf_classes_linked; }
+  static PerfCounter* perf_class_link_time() { return _perf_class_link_time; }
+
+  // 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
+};