//===-- AppleObjCClassDescriptorV2.cpp -----------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "AppleObjCClassDescriptorV2.h"

using namespace lldb;
using namespace lldb_private;

bool
ClassDescriptorV2::Read_objc_class (Process* process, std::unique_ptr<objc_class_t> &objc_class) const
{
    objc_class.reset(new objc_class_t);
    
    bool ret = objc_class->Read (process, m_objc_class_ptr);
    
    if (!ret)
        objc_class.reset();
    
    return ret;
}

bool
ClassDescriptorV2::objc_class_t::Read(Process *process, lldb::addr_t addr)
{
    size_t ptr_size = process->GetAddressByteSize();
    
    size_t objc_class_size = ptr_size   // uintptr_t isa;
    + ptr_size   // Class superclass;
    + ptr_size   // void *cache;
    + ptr_size   // IMP *vtable;
    + ptr_size;  // uintptr_t data_NEVER_USE;
    
    DataBufferHeap objc_class_buf (objc_class_size, '\0');
    Error error;
    
    process->ReadMemory(addr, objc_class_buf.GetBytes(), objc_class_size, error);
    if (error.Fail())
    {
        return false;
    }
    
    DataExtractor extractor(objc_class_buf.GetBytes(), objc_class_size, process->GetByteOrder(), process->GetAddressByteSize());
    
    lldb::offset_t cursor = 0;
    
    m_isa           = extractor.GetAddress_unchecked(&cursor);   // uintptr_t isa;
    m_superclass    = extractor.GetAddress_unchecked(&cursor);   // Class superclass;
    m_cache_ptr     = extractor.GetAddress_unchecked(&cursor);   // void *cache;
    m_vtable_ptr    = extractor.GetAddress_unchecked(&cursor);   // IMP *vtable;
    lldb::addr_t data_NEVER_USE = extractor.GetAddress_unchecked(&cursor);   // uintptr_t data_NEVER_USE;
    
    m_flags         = (uint8_t)(data_NEVER_USE & (lldb::addr_t)3);
    m_data_ptr      = data_NEVER_USE & ~(lldb::addr_t)3;
    
    return true;
}

bool
ClassDescriptorV2::class_rw_t::Read(Process *process, lldb::addr_t addr)
{
    size_t ptr_size = process->GetAddressByteSize();
    
    size_t size = sizeof(uint32_t)  // uint32_t flags;
    + sizeof(uint32_t)  // uint32_t version;
    + ptr_size          // const class_ro_t *ro;
    + ptr_size          // union { method_list_t **method_lists; method_list_t *method_list; };
    + ptr_size          // struct chained_property_list *properties;
    + ptr_size          // const protocol_list_t **protocols;
    + ptr_size          // Class firstSubclass;
    + ptr_size;         // Class nextSiblingClass;
    
    DataBufferHeap buffer (size, '\0');
    Error error;
    
    process->ReadMemory(addr, buffer.GetBytes(), size, error);
    if (error.Fail())
    {
        return false;
    }
    
    DataExtractor extractor(buffer.GetBytes(), size, process->GetByteOrder(), process->GetAddressByteSize());
    
    lldb::offset_t cursor = 0;
    
    m_flags             = extractor.GetU32_unchecked(&cursor);
    m_version           = extractor.GetU32_unchecked(&cursor);
    m_ro_ptr            = extractor.GetAddress_unchecked(&cursor);
    m_method_list_ptr   = extractor.GetAddress_unchecked(&cursor);
    m_properties_ptr    = extractor.GetAddress_unchecked(&cursor);
    m_firstSubclass     = extractor.GetAddress_unchecked(&cursor);
    m_nextSiblingClass  = extractor.GetAddress_unchecked(&cursor);
    
    return true;
}

bool
ClassDescriptorV2::class_ro_t::Read(Process *process, lldb::addr_t addr)
{
    size_t ptr_size = process->GetAddressByteSize();
    
    size_t size = sizeof(uint32_t)             // uint32_t flags;
    + sizeof(uint32_t)                         // uint32_t instanceStart;
    + sizeof(uint32_t)                         // uint32_t instanceSize;
    + (ptr_size == 8 ? sizeof(uint32_t) : 0)   // uint32_t reserved; // __LP64__ only
    + ptr_size                                 // const uint8_t *ivarLayout;
    + ptr_size                                 // const char *name;
    + ptr_size                                 // const method_list_t *baseMethods;
    + ptr_size                                 // const protocol_list_t *baseProtocols;
    + ptr_size                                 // const ivar_list_t *ivars;
    + ptr_size                                 // const uint8_t *weakIvarLayout;
    + ptr_size;                                // const property_list_t *baseProperties;
    
    DataBufferHeap buffer (size, '\0');
    Error error;
    
    process->ReadMemory(addr, buffer.GetBytes(), size, error);
    if (error.Fail())
    {
        return false;
    }
    
    DataExtractor extractor(buffer.GetBytes(), size, process->GetByteOrder(), process->GetAddressByteSize());
    
    lldb::offset_t cursor = 0;
    
    m_flags             = extractor.GetU32_unchecked(&cursor);
    m_instanceStart     = extractor.GetU32_unchecked(&cursor);
    m_instanceSize      = extractor.GetU32_unchecked(&cursor);
    if (ptr_size == 8)
        m_reserved      = extractor.GetU32_unchecked(&cursor);
    else
        m_reserved      = 0;
    m_ivarLayout_ptr     = extractor.GetAddress_unchecked(&cursor);
    m_name_ptr           = extractor.GetAddress_unchecked(&cursor);
    m_baseMethods_ptr    = extractor.GetAddress_unchecked(&cursor);
    m_baseProtocols_ptr  = extractor.GetAddress_unchecked(&cursor);
    m_ivars_ptr          = extractor.GetAddress_unchecked(&cursor);
    m_weakIvarLayout_ptr = extractor.GetAddress_unchecked(&cursor);
    m_baseProperties_ptr = extractor.GetAddress_unchecked(&cursor);
    
    DataBufferHeap name_buf(1024, '\0');
    
    process->ReadCStringFromMemory(m_name_ptr, (char*)name_buf.GetBytes(), name_buf.GetByteSize(), error);
    
    if (error.Fail())
    {
        return false;
    }
    
    m_name.assign((char*)name_buf.GetBytes());
    
    return true;
}

bool
ClassDescriptorV2::Read_class_row (Process* process, const objc_class_t &objc_class, std::unique_ptr<class_ro_t> &class_ro, std::unique_ptr<class_rw_t> &class_rw) const
{
    class_ro.reset();
    class_rw.reset();
    
    Error error;
    uint32_t class_row_t_flags = process->ReadUnsignedIntegerFromMemory(objc_class.m_data_ptr, sizeof(uint32_t), 0, error);
    if (!error.Success())
        return false;
    
    if (class_row_t_flags & RW_REALIZED)
    {
        class_rw.reset(new class_rw_t);
        
        if (!class_rw->Read(process, objc_class.m_data_ptr))
        {
            class_rw.reset();
            return false;
        }
        
        class_ro.reset(new class_ro_t);
        
        if (!class_ro->Read(process, class_rw->m_ro_ptr))
        {
            class_rw.reset();
            class_ro.reset();
            return false;
        }
    }
    else
    {
        class_ro.reset(new class_ro_t);
        
        if (!class_ro->Read(process, objc_class.m_data_ptr))
        {
            class_ro.reset();
            return false;
        }
    }
    
    return true;
}

bool
ClassDescriptorV2::method_list_t::Read(Process *process, lldb::addr_t addr)
{
    size_t size = sizeof(uint32_t)  // uint32_t entsize_NEVER_USE;
    + sizeof(uint32_t); // uint32_t count;
    
    DataBufferHeap buffer (size, '\0');
    Error error;
    
    process->ReadMemory(addr, buffer.GetBytes(), size, error);
    if (error.Fail())
    {
        return false;
    }
    
    DataExtractor extractor(buffer.GetBytes(), size, process->GetByteOrder(), process->GetAddressByteSize());
    
    lldb::offset_t cursor = 0;
    
    m_entsize   = extractor.GetU32_unchecked(&cursor) & ~(uint32_t)3;
    m_count     = extractor.GetU32_unchecked(&cursor);
    m_first_ptr  = addr + cursor;
    
    return true;
}

bool
ClassDescriptorV2::method_t::Read(Process *process, lldb::addr_t addr)
{
    size_t size = GetSize(process);
    
    DataBufferHeap buffer (size, '\0');
    Error error;
    
    process->ReadMemory(addr, buffer.GetBytes(), size, error);
    if (error.Fail())
    {
        return false;
    }
    
    DataExtractor extractor(buffer.GetBytes(), size, process->GetByteOrder(), process->GetAddressByteSize());
    
    lldb::offset_t cursor = 0;
    
    m_name_ptr   = extractor.GetAddress_unchecked(&cursor);
    m_types_ptr  = extractor.GetAddress_unchecked(&cursor);
    m_imp_ptr    = extractor.GetAddress_unchecked(&cursor);
    
    const size_t buffer_size = 1024;
    size_t count;
    
    DataBufferHeap string_buf(buffer_size, 0);
    
    count = process->ReadCStringFromMemory(m_name_ptr, (char*)string_buf.GetBytes(), buffer_size, error);
    m_name.assign((char*)string_buf.GetBytes(), count);
    
    count = process->ReadCStringFromMemory(m_types_ptr, (char*)string_buf.GetBytes(), buffer_size, error);
    m_types.assign((char*)string_buf.GetBytes(), count);
    
    return true;
}

bool
ClassDescriptorV2::ivar_list_t::Read(Process *process, lldb::addr_t addr)
{
    size_t size = sizeof(uint32_t)  // uint32_t entsize;
    + sizeof(uint32_t); // uint32_t count;
    
    DataBufferHeap buffer (size, '\0');
    Error error;
    
    process->ReadMemory(addr, buffer.GetBytes(), size, error);
    if (error.Fail())
    {
        return false;
    }
    
    DataExtractor extractor(buffer.GetBytes(), size, process->GetByteOrder(), process->GetAddressByteSize());
    
    lldb::offset_t cursor = 0;
    
    m_entsize   = extractor.GetU32_unchecked(&cursor);
    m_count     = extractor.GetU32_unchecked(&cursor);
    m_first_ptr = addr + cursor;
    
    return true;
}

bool
ClassDescriptorV2::ivar_t::Read(Process *process, lldb::addr_t addr)
{
    size_t size = GetSize(process);
    
    DataBufferHeap buffer (size, '\0');
    Error error;
    
    process->ReadMemory(addr, buffer.GetBytes(), size, error);
    if (error.Fail())
    {
        return false;
    }
    
    DataExtractor extractor(buffer.GetBytes(), size, process->GetByteOrder(), process->GetAddressByteSize());
    
    lldb::offset_t cursor = 0;
    
    m_offset_ptr = extractor.GetAddress_unchecked(&cursor);
    m_name_ptr   = extractor.GetAddress_unchecked(&cursor);
    m_type_ptr   = extractor.GetAddress_unchecked(&cursor);
    m_alignment  = extractor.GetU32_unchecked(&cursor);
    m_size       = extractor.GetU32_unchecked(&cursor);
    
    const size_t buffer_size = 1024;
    size_t count;
    
    DataBufferHeap string_buf(buffer_size, 0);
    
    count = process->ReadCStringFromMemory(m_name_ptr, (char*)string_buf.GetBytes(), buffer_size, error);
    m_name.assign((char*)string_buf.GetBytes(), count);
    
    count = process->ReadCStringFromMemory(m_type_ptr, (char*)string_buf.GetBytes(), buffer_size, error);
    m_type.assign((char*)string_buf.GetBytes(), count);
    
    return true;
}

bool
ClassDescriptorV2::Describe (std::function <void (ObjCLanguageRuntime::ObjCISA)> const &superclass_func,
                             std::function <bool (const char *, const char *)> const &instance_method_func,
                             std::function <bool (const char *, const char *)> const &class_method_func,
                             std::function <bool (const char *, const char *, lldb::addr_t, uint64_t)> const &ivar_func) const
{
    lldb_private::Process *process = m_runtime.GetProcess();
    
    std::unique_ptr<objc_class_t> objc_class;
    std::unique_ptr<class_ro_t> class_ro;
    std::unique_ptr<class_rw_t> class_rw;
    
    if (!Read_objc_class(process, objc_class))
        return 0;
    if (!Read_class_row(process, *objc_class, class_ro, class_rw))
        return 0;
    
    static ConstString NSObject_name("NSObject");
    
    if (m_name != NSObject_name && superclass_func)
        superclass_func(objc_class->m_superclass);
    
    if (instance_method_func)
    {
        std::unique_ptr<method_list_t> base_method_list;
        
        base_method_list.reset(new method_list_t);
        if (!base_method_list->Read(process, class_ro->m_baseMethods_ptr))
            return false;
        
        if (base_method_list->m_entsize != method_t::GetSize(process))
            return false;
        
        std::unique_ptr<method_t> method;
        method.reset(new method_t);
        
        for (uint32_t i = 0, e = base_method_list->m_count; i < e; ++i)
        {
            method->Read(process, base_method_list->m_first_ptr + (i * base_method_list->m_entsize));
            
            if (instance_method_func(method->m_name.c_str(), method->m_types.c_str()))
                break;
        }
    }
    
    if (class_method_func)
    {
        AppleObjCRuntime::ClassDescriptorSP metaclass(GetMetaclass());
        
        // We don't care about the metaclass's superclass, or its class methods.  Its instance methods are
        // our class methods.
        
        if (metaclass) {
            metaclass->Describe(std::function <void (ObjCLanguageRuntime::ObjCISA)> (nullptr),
                                class_method_func,
                                std::function <bool (const char *, const char *)> (nullptr),
                                std::function <bool (const char *, const char *, lldb::addr_t, uint64_t)> (nullptr));
        }
    }
    
    if (ivar_func)
    {
        if (class_ro->m_ivars_ptr != 0)
        {            
            ivar_list_t ivar_list;
            if (!ivar_list.Read(process, class_ro->m_ivars_ptr))
                return false;
            
            if (ivar_list.m_entsize != ivar_t::GetSize(process))
                return false;
            
            ivar_t ivar;
            
            for (uint32_t i = 0, e = ivar_list.m_count; i < e; ++i)
            {
                ivar.Read(process, ivar_list.m_first_ptr + (i * ivar_list.m_entsize));
                
                if (ivar_func(ivar.m_name.c_str(), ivar.m_type.c_str(), ivar.m_offset_ptr, ivar.m_size))
                    break;
            }
        }
    }
    
    return true;
}

ConstString
ClassDescriptorV2::GetClassName ()
{
    if (!m_name)
    {
        lldb_private::Process *process = m_runtime.GetProcess();
        
        if (process)
        {
            std::unique_ptr<objc_class_t> objc_class;
            std::unique_ptr<class_ro_t> class_ro;
            std::unique_ptr<class_rw_t> class_rw;
            
            if (!Read_objc_class(process, objc_class))
                return m_name;
            if (!Read_class_row(process, *objc_class, class_ro, class_rw))
                return m_name;
            
            m_name = ConstString(class_ro->m_name.c_str());
        }
    }
    return m_name;
}

ObjCLanguageRuntime::ClassDescriptorSP
ClassDescriptorV2::GetSuperclass ()
{
    lldb_private::Process *process = m_runtime.GetProcess();
    
    if (!process)
        return ObjCLanguageRuntime::ClassDescriptorSP();
    
    std::unique_ptr<objc_class_t> objc_class;
    
    if (!Read_objc_class(process, objc_class))
        return ObjCLanguageRuntime::ClassDescriptorSP();
    
    return m_runtime.ObjCLanguageRuntime::GetClassDescriptorFromISA(objc_class->m_superclass);
}

ObjCLanguageRuntime::ClassDescriptorSP
ClassDescriptorV2::GetMetaclass () const
{
    lldb_private::Process *process = m_runtime.GetProcess();
    
    if (!process)
        return ObjCLanguageRuntime::ClassDescriptorSP();
    
    std::unique_ptr<objc_class_t> objc_class;
    
    if (!Read_objc_class(process, objc_class))
        return ObjCLanguageRuntime::ClassDescriptorSP();
    
    lldb::addr_t candidate_isa = m_runtime.GetPointerISA(objc_class->m_isa);
    
    return ObjCLanguageRuntime::ClassDescriptorSP(new ClassDescriptorV2(m_runtime, candidate_isa, nullptr));
}

uint64_t
ClassDescriptorV2::GetInstanceSize ()
{
    lldb_private::Process *process = m_runtime.GetProcess();
    
    if (process)
    {
        std::unique_ptr<objc_class_t> objc_class;
        std::unique_ptr<class_ro_t> class_ro;
        std::unique_ptr<class_rw_t> class_rw;
        
        if (!Read_objc_class(process, objc_class))
            return 0;
        if (!Read_class_row(process, *objc_class, class_ro, class_rw))
            return 0;
        
        return class_ro->m_instanceSize;
    }
    
    return 0;
}

ClassDescriptorV2::iVarsStorage::iVarsStorage ():
m_filled(false),
m_ivars(),
m_mutex(Mutex::eMutexTypeRecursive)
{}

size_t
ClassDescriptorV2::iVarsStorage::size ()
{
    return m_ivars.size();
}

ClassDescriptorV2::iVarDescriptor&
ClassDescriptorV2::iVarsStorage::operator[] (size_t idx)
{
    return m_ivars[idx];
}

void
ClassDescriptorV2::iVarsStorage::fill (AppleObjCRuntimeV2& runtime, ClassDescriptorV2& descriptor)
{
    if (m_filled)
        return;
    Mutex::Locker lock(m_mutex);
    m_filled = true;
    ObjCLanguageRuntime::EncodingToTypeSP encoding_to_type_sp(runtime.GetEncodingToType());
    Process* process(runtime.GetProcess());
    if (!encoding_to_type_sp)
        return;
    descriptor.Describe(nullptr,
                        nullptr,
                        nullptr,
                        [this,process,encoding_to_type_sp](const char * name, const char * type, lldb::addr_t offset_ptr, uint64_t size) -> bool {
                 const bool for_expression = false;
                 const bool stop_loop = false;
                 ClangASTType ivar_type = encoding_to_type_sp->RealizeType(type, for_expression);
                 if (ivar_type)
                 {
                     Scalar offset_scalar;
                     Error error;
                     size_t read = process->ReadScalarIntegerFromMemory(offset_ptr, 4, true, offset_scalar, error);
                     if (error.Success() && 4 == read)
                         m_ivars.push_back({ ConstString(name), ivar_type, size, offset_scalar.SInt() });
                 }
                 return stop_loop;
             });
}

void
ClassDescriptorV2::GetIVarInformation ()
{
    m_ivars_storage.fill(m_runtime, *this);
}
