468 lines
12 KiB
C++
468 lines
12 KiB
C++
// natClassLoader.cc - Implementation of java.lang.ClassLoader native methods.
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/* Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation
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This file is part of libgcj.
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This software is copyrighted work licensed under the terms of the
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Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
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details. */
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/* Author: Kresten Krab Thorup <krab@gnu.org> */
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#include <config.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <gcj/cni.h>
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#include <jvm.h>
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#include <execution.h>
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#include <java-threads.h>
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#include <java-interp.h>
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#include <java/lang/Character.h>
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#include <java/lang/Thread.h>
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#include <java/lang/ClassLoader.h>
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#include <gnu/gcj/runtime/VMClassLoader.h>
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#include <java/lang/InternalError.h>
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#include <java/lang/IllegalAccessError.h>
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#include <java/lang/LinkageError.h>
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#include <java/lang/NoClassDefFoundError.h>
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#include <java/lang/ClassNotFoundException.h>
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#include <java/lang/ClassCircularityError.h>
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#include <java/lang/IncompatibleClassChangeError.h>
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#include <java/lang/ClassFormatError.h>
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#include <java/lang/VirtualMachineError.h>
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#include <java/lang/VMClassLoader.h>
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#include <java/lang/reflect/Modifier.h>
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#include <java/lang/Runtime.h>
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#include <java/lang/StringBuffer.h>
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#include <java/io/Serializable.h>
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#include <java/lang/Cloneable.h>
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//
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// A single class can have many "initiating" class loaders,
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// and a single "defining" class loader. The Defining
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// class loader is what is returned from Class.getClassLoader()
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// and is used when loading dependent classes during resolution.
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// The set of initiating class loaders are used to ensure
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// safety of linking, and is maintained in the hash table
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// "initiated_classes". A defining classloader is by definition also
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// initiating, so we only store classes in this table if they have more
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// than one class loader associated.
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//
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// Size of local hash table.
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#define HASH_LEN 1013
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// Hash function for Utf8Consts.
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#define HASH_UTF(Utf) ((Utf)->hash16() % HASH_LEN)
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struct _Jv_LoaderInfo
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{
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_Jv_LoaderInfo *next;
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java::lang::Class *klass;
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java::lang::ClassLoader *loader;
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};
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static _Jv_LoaderInfo *initiated_classes[HASH_LEN];
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static jclass loaded_classes[HASH_LEN];
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// This is the root of a linked list of classes
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static jclass stack_head;
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jclass
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_Jv_FindClassInCache (_Jv_Utf8Const *name, java::lang::ClassLoader *loader)
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{
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JvSynchronize sync (&java::lang::Class::class$);
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jint hash = HASH_UTF (name);
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if (loader && loader == java::lang::ClassLoader::getSystemClassLoader())
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loader = NULL;
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// first, if LOADER is a defining loader, then it is also initiating
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jclass klass;
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for (klass = loaded_classes[hash]; klass; klass = klass->next)
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{
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if (loader == klass->loader && _Jv_equalUtf8Consts (name, klass->name))
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break;
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}
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// otherwise, it may be that the class in question was defined
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// by some other loader, but that the loading was initiated by
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// the loader in question.
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if (!klass)
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{
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_Jv_LoaderInfo *info;
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for (info = initiated_classes[hash]; info; info = info->next)
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{
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if (loader == info->loader
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&& _Jv_equalUtf8Consts (name, info->klass->name))
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{
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klass = info->klass;
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break;
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}
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}
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}
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return klass;
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}
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void
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_Jv_UnregisterClass (jclass the_class)
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{
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JvSynchronize sync (&java::lang::Class::class$);
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jint hash = HASH_UTF(the_class->name);
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jclass *klass = &(loaded_classes[hash]);
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for ( ; *klass; klass = &((*klass)->next))
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{
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if (*klass == the_class)
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{
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*klass = (*klass)->next;
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break;
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}
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}
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_Jv_LoaderInfo **info = &(initiated_classes[hash]);
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for ( ; ; info = &((*info)->next))
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{
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while (*info && (*info)->klass == the_class)
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{
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_Jv_LoaderInfo *old = *info;
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*info = (*info)->next;
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_Jv_Free (old);
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}
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if (*info == NULL)
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break;
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}
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}
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void
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_Jv_RegisterInitiatingLoader (jclass klass, java::lang::ClassLoader *loader)
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{
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if (loader && loader == java::lang::ClassLoader::getSystemClassLoader())
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loader = NULL;
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// This information can't be visible to the GC.
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_Jv_LoaderInfo *info
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= (_Jv_LoaderInfo *) _Jv_Malloc (sizeof(_Jv_LoaderInfo));
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jint hash = HASH_UTF(klass->name);
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JvSynchronize sync (&java::lang::Class::class$);
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info->loader = loader;
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info->klass = klass;
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info->next = initiated_classes[hash];
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initiated_classes[hash] = info;
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}
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// This function is called many times during startup, before main() is
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// run. At that point in time we know for certain we are running
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// single-threaded, so we don't need to lock when adding classes to the
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// class chain. At all other times, the caller should synchronize on
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// Class::class$.
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void
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_Jv_RegisterClasses (const jclass *classes)
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{
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for (; *classes; ++classes)
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{
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jclass klass = *classes;
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(*_Jv_RegisterClassHook) (klass);
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}
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}
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// This is a version of _Jv_RegisterClasses that takes a count.
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void
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_Jv_RegisterClasses_Counted (const jclass * classes, size_t count)
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{
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size_t i;
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for (i = 0; i < count; i++)
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{
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jclass klass = classes[i];
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(*_Jv_RegisterClassHook) (klass);
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}
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}
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void
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_Jv_RegisterClassHookDefault (jclass klass)
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{
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jint hash = HASH_UTF (klass->name);
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// The BC ABI makes this check unnecessary: we always resolve all
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// data references via the appropriate class loader, so the kludge
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// that required this check has gone.
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// If the class is already registered, don't re-register it.
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jclass check_class = klass->next;
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while (check_class != NULL)
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{
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if (check_class == klass)
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{
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// If you get this, it means you have the same class in two
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// different libraries.
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#define TEXT "Duplicate class registration: "
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// We size-limit MESSAGE so that you can't trash the stack.
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char message[200];
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strcpy (message, TEXT);
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strncpy (message + sizeof (TEXT) - 1, klass->name->chars(),
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sizeof (message) - sizeof (TEXT));
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message[sizeof (message) - 1] = '\0';
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if (! gcj::runtimeInitialized)
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JvFail (message);
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else
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{
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java::lang::String *str = JvNewStringLatin1 (message);
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throw new java::lang::VirtualMachineError (str);
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}
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}
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check_class = check_class->next;
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}
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// FIXME: this is really bogus!
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if (! klass->engine)
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klass->engine = &_Jv_soleCompiledEngine;
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klass->next = loaded_classes[hash];
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loaded_classes[hash] = klass;
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}
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// A pointer to a function that actually registers a class.
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// Normally _Jv_RegisterClassHookDefault, but could be some other function
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// that registers the class in e.g. a ClassLoader-local table.
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// Should synchronize on Class:class$ while setting/restore this variable.
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void (*_Jv_RegisterClassHook) (jclass cl) = _Jv_RegisterClassHookDefault;
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void
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_Jv_RegisterClass (jclass klass)
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{
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jclass classes[2];
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classes[0] = klass;
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classes[1] = NULL;
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_Jv_RegisterClasses (classes);
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}
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jclass
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_Jv_FindClass (_Jv_Utf8Const *name, java::lang::ClassLoader *loader)
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{
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jclass klass = _Jv_FindClassInCache (name, loader);
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if (! klass)
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{
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jstring sname = name->toString();
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java::lang::ClassLoader *sys
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= java::lang::ClassLoader::getSystemClassLoader ();
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if (loader)
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{
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// Load using a user-defined loader, jvmspec 5.3.2
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klass = loader->loadClass(sname, false);
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// If "loader" delegated the loadClass operation to another
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// loader, explicitly register that it is also an initiating
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// loader of the given class.
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java::lang::ClassLoader *delegate = (loader == sys
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? NULL
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: loader);
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if (klass && klass->getClassLoaderInternal () != delegate)
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_Jv_RegisterInitiatingLoader (klass, loader);
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}
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else
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{
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// Load using the bootstrap loader jvmspec 5.3.1.
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klass = sys->loadClass (sname, false);
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// Register that we're an initiating loader.
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if (klass)
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_Jv_RegisterInitiatingLoader (klass, 0);
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}
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}
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else
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{
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// we need classes to be in the hash while
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// we're loading, so that they can refer to themselves.
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_Jv_Linker::wait_for_state (klass, JV_STATE_LOADED);
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}
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return klass;
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}
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jclass
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_Jv_NewClass (_Jv_Utf8Const *name, jclass superclass,
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java::lang::ClassLoader *loader)
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{
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jclass ret = (jclass) _Jv_AllocObject (&java::lang::Class::class$);
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ret->name = name;
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ret->superclass = superclass;
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ret->loader = loader;
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_Jv_RegisterClass (ret);
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return ret;
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}
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static _Jv_IDispatchTable *array_idt = NULL;
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static jshort array_depth = 0;
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static jclass *array_ancestors = NULL;
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// Create a class representing an array of ELEMENT and store a pointer to it
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// in element->arrayclass. LOADER is the ClassLoader which _initiated_ the
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// instantiation of this array. ARRAY_VTABLE is the vtable to use for the new
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// array class. This parameter is optional.
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void
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_Jv_NewArrayClass (jclass element, java::lang::ClassLoader *loader,
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_Jv_VTable *array_vtable)
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{
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JvSynchronize sync (element);
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_Jv_Utf8Const *array_name;
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int len;
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if (element->arrayclass)
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return;
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if (element->isPrimitive())
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{
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if (element == JvPrimClass (void))
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throw new java::lang::ClassNotFoundException ();
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len = 3;
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}
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else
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len = element->name->len() + 5;
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{
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char signature[len];
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int index = 0;
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signature[index++] = '[';
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// Compute name of array class.
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if (element->isPrimitive())
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{
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signature[index++] = (char) element->method_count;
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}
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else
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{
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size_t length = element->name->len();
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const char *const name = element->name->chars();
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if (name[0] != '[')
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signature[index++] = 'L';
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memcpy (&signature[index], name, length);
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index += length;
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if (name[0] != '[')
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signature[index++] = ';';
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}
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array_name = _Jv_makeUtf8Const (signature, index);
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}
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// Create new array class.
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jclass array_class = _Jv_NewClass (array_name, &java::lang::Object::class$,
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element->loader);
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// Note that `vtable_method_count' doesn't include the initial
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// gc_descr slot.
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JvAssert (java::lang::Object::class$.vtable_method_count
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== NUM_OBJECT_METHODS);
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int dm_count = java::lang::Object::class$.vtable_method_count;
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// Create a new vtable by copying Object's vtable.
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_Jv_VTable *vtable;
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if (array_vtable)
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vtable = array_vtable;
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else
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vtable = _Jv_VTable::new_vtable (dm_count);
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vtable->clas = array_class;
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vtable->gc_descr = java::lang::Object::class$.vtable->gc_descr;
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for (int i = 0; i < dm_count; ++i)
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vtable->set_method (i, java::lang::Object::class$.vtable->get_method (i));
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array_class->vtable = vtable;
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array_class->vtable_method_count
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= java::lang::Object::class$.vtable_method_count;
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// Stash the pointer to the element type.
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array_class->methods = (_Jv_Method *) element;
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// Register our interfaces.
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static jclass interfaces[] =
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{
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&java::lang::Cloneable::class$,
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&java::io::Serializable::class$
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};
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array_class->interfaces = interfaces;
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array_class->interface_count = sizeof interfaces / sizeof interfaces[0];
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// Since all array classes have the same interface dispatch table, we can
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// cache one and reuse it. It is not necessary to synchronize this.
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if (!array_idt)
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{
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_Jv_Linker::wait_for_state(array_class, JV_STATE_PREPARED);
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array_idt = array_class->idt;
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array_depth = array_class->depth;
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array_ancestors = array_class->ancestors;
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}
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else
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{
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array_class->idt = array_idt;
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array_class->depth = array_depth;
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array_class->ancestors = array_ancestors;
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}
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using namespace java::lang::reflect;
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{
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// Array classes are "abstract final" and inherit accessibility
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// from element type, per vmspec 5.3.3.2
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_Jv_ushort accflags = (Modifier::FINAL | Modifier::ABSTRACT
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| (element->accflags
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& (Modifier::PUBLIC | Modifier::PROTECTED
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| Modifier::PRIVATE)));
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array_class->accflags = accflags;
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}
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// An array class has no visible instance fields. "length" is invisible to
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// reflection.
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// Say this class is initialized and ready to go!
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array_class->state = JV_STATE_DONE;
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// vmspec, section 5.3.3 describes this
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if (element->loader != loader)
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_Jv_RegisterInitiatingLoader (array_class, loader);
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element->arrayclass = array_class;
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}
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// These two functions form a stack of classes. When a class is loaded
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// it is pushed onto the stack by the class loader; this is so that
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// StackTrace can quickly determine which classes have been loaded.
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jclass
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_Jv_PopClass (void)
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{
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JvSynchronize sync (&java::lang::Class::class$);
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if (stack_head)
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{
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jclass tmp = stack_head;
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stack_head = tmp->chain;
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return tmp;
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}
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return NULL;
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}
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void
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_Jv_PushClass (jclass k)
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{
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JvSynchronize sync (&java::lang::Class::class$);
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jclass tmp = stack_head;
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stack_head = k;
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k->chain = tmp;
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}
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