llvm/lldb/include/lldb/Symbol/ObjectContainer.h

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

#ifndef liblldb_ObjectContainer_h_
#define liblldb_ObjectContainer_h_

// C Includes
// C++ Includes
// Other libraries and framework includes
// Project includes

#include "lldb/lldb-private.h"
#include "lldb/Core/DataExtractor.h"
#include "lldb/Host/FileSpec.h"
#include "lldb/Core/ModuleChild.h"
#include "lldb/Core/PluginInterface.h"
#include "lldb/Host/Endian.h"

namespace lldb_private {

//----------------------------------------------------------------------
/// @class ObjectContainer ObjectContainer.h "lldb/Symbol/ObjectContainer.h"
/// @brief A plug-in interface definition class for object containers.
///
/// Object containers contain object files from one or more
/// architectures, and also can contain one or more named objects.
///
/// Typical object containers are static libraries (.a files) that
/// contain multiple named object files, and universal files that contain
/// multiple architectures.
//----------------------------------------------------------------------
class ObjectContainer :
    public PluginInterface,
    public ModuleChild
{
public:
    //------------------------------------------------------------------
    /// Construct with a parent module, offset, and header data.
    ///
    /// Object files belong to modules and a valid module must be
    /// supplied upon construction. The at an offset within a file for
    /// objects that contain more than one architecture or object.
    //------------------------------------------------------------------
    ObjectContainer (const lldb::ModuleSP &module_sp,
                     const FileSpec *file,
                     lldb::offset_t file_offset,
                     lldb::offset_t length,
                     lldb::DataBufferSP& data_sp,
                     lldb::offset_t data_offset) :
        ModuleChild (module_sp),
        m_file (),  // This file can be different than the module's file spec
        m_offset (file_offset),
        m_length (length),
        m_data ()
    {
        if (file)
            m_file = *file;
        if (data_sp)
            m_data.SetData (data_sp, data_offset, length);
    }

    //------------------------------------------------------------------
    /// Destructor.
    ///
    /// The destructor is virtual since this class is designed to be
    /// inherited from by the plug-in instance.
    //------------------------------------------------------------------
    virtual
    ~ObjectContainer()
    {
    }

    //------------------------------------------------------------------
    /// Dump a description of this object to a Stream.
    ///
    /// Dump a description of the current contents of this object
    /// to the supplied stream \a s. The dumping should include the
    /// section list if it has been parsed, and the symbol table
    /// if it has been parsed.
    ///
    /// @param[in] s
    ///     The stream to which to dump the object descripton.
    //------------------------------------------------------------------
    virtual void
    Dump (Stream *s) const = 0;

    //------------------------------------------------------------------
    /// Gets the architecture given an index.
    ///
    /// Copies the architecture specification for index \a idx.
    ///
    /// @param[in] idx
    ///     The architecture index to extract.
    ///
    /// @param[out] arch
    ///     A architecture object that will be filled in if \a idx is a
    ///     architecture valid index.
    ///
    /// @return
    ///     Returns \b true if \a idx is valid and \a arch has been
    ///     filled in, \b false otherwise.
    ///
    /// @see ObjectContainer::GetNumArchitectures() const
    //------------------------------------------------------------------
    virtual bool
    GetArchitectureAtIndex (uint32_t idx, ArchSpec& arch) const
    {
        return false;
    }

    //------------------------------------------------------------------
    /// Returns the offset into a file at which this object resides.
    ///
    /// Some files contain many object files, and this function allows
    /// access to an object's offset within the file.
    ///
    /// @return
    ///     The offset in bytes into the file. Defaults to zero for
    ///     simple object files that a represented by an entire file.
    //------------------------------------------------------------------
    virtual lldb::addr_t
    GetOffset () const
    { return m_offset; }

    virtual lldb::addr_t
    GetByteSize () const
    { return m_length; }

    //------------------------------------------------------------------
    /// Get the number of objects within this object file (archives).
    ///
    /// @return
    ///     Zero for object files that are not archives, or the number
    ///     of objects contained in the archive.
    //------------------------------------------------------------------
    virtual size_t
    GetNumObjects () const
    { return 0; }

    //------------------------------------------------------------------
    /// Get the number of architectures in this object file.
    ///
    /// The default implementation returns 1 as for object files that
    /// contain a single architecture. ObjectContainer instances that
    /// contain more than one architecture should override this function
    /// and return an appropriate value.
    ///
    /// @return
    ///     The number of architectures contained in this object file.
    //------------------------------------------------------------------
    virtual size_t
    GetNumArchitectures () const
    { return 0; }

    //------------------------------------------------------------------
    /// Attempts to parse the object header.
    ///
    /// This function is used as a test to see if a given plug-in
    /// instance can parse the header data already contained in
    /// ObjectContainer::m_data. If an object file parser does not
    /// recognize that magic bytes in a header, false should be returned
    /// and the next plug-in can attempt to parse an object file.
    ///
    /// @return
    ///     Returns \b true if the header was parsed succesfully, \b
    ///     false otherwise.
    //------------------------------------------------------------------
    virtual bool
    ParseHeader () = 0;

    //------------------------------------------------------------------
    /// Selects an architecture in an object file.
    ///
    /// Object files that contain a single architecture should verify
    /// that the specified \a arch matches the architecture in in
    /// object file and return \b true or \b false accordingly.
    ///
    /// Object files that contain more than one architecture should
    /// attempt to select that architecture, and if successful, clear
    /// out any previous state from any previously selected architecture
    /// and prepare to return information for the new architecture.
    ///
    /// @return
    ///     Returns a pointer to the object file of the requested \a
    ///     arch and optional \a name. Returns NULL of no such object
    ///     file exists in the container.
    //------------------------------------------------------------------
    virtual lldb::ObjectFileSP
    GetObjectFile (const FileSpec *file) = 0;

    virtual bool
    ObjectAtIndexIsContainer (uint32_t object_idx)
    {
        return false;
    }

    virtual ObjectFile *
    GetObjectFileAtIndex (uint32_t object_idx)
    {
        return NULL;
    }

    virtual ObjectContainer *
    GetObjectContainerAtIndex (uint32_t object_idx)
    {
        return NULL;
    }

    virtual const char *
    GetObjectNameAtIndex (uint32_t object_idx) const
    {
        return NULL;
    }

protected:
    //------------------------------------------------------------------
    // Member variables.
    //------------------------------------------------------------------
    FileSpec m_file; ///< The file that represents this container objects (which can be different from the module's file).
    lldb::addr_t m_offset; ///< The offset in bytes into the file, or the address in memory
    lldb::addr_t m_length; ///< The size in bytes if known (can be zero).
    DataExtractor m_data; ///< The data for this object file so things can be parsed lazily.

private:
    DISALLOW_COPY_AND_ASSIGN (ObjectContainer);
};

} // namespace lldb_private

#endif  // liblldb_ObjectContainer_h_