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[gtkD.git] / srcgl / lib / Loader.d

/*
 * MODULE: loader.d 
 * 
 * Dynamic Library Loader for DUI
 *
 * Added 2004-12-11 -- John Reimer
 * Updated 2005-02-21: class and symbol names change; versioning modification.
 * Updated 2005-05-04: repairs to support linux
 *
 * Design/implementation of loader module inspired by Kris Bell's ICU.d dynamic 
 * loader -- mango.icu
 *
 * Thanks Kris! see www.dsource.org/projects/mango for more details.
 *
 */
 
module lib.Loader;

//debug = loadLib;
//debug = loadSymbol;

alias void* HANDLE;

version (Windows) 
{
        extern(Windows) 
        {
                HANDLE LoadLibraryA( char* );
                void* GetProcAddress( void*, char* );
        }
        // getSymbol - cross-platform access point
        alias GetProcAddress getSymbol;
}

version (linux)
{
        extern(C)
        {
                
                void* dlopen(char*, int);
                char* dlerror();
                void* dlsym(void*,char*);
                int   dlclose(void*);
        }
//      // getSymbol - cross-platform access point
        alias dlsym getSymbol;
}       

version (Darwin)
{
        private void* getSymbol(void* handle,char* name) {}
}


/* 
 *  ProcLink is used to record the library, function, and function name
 *  that will be loaded by dynamic loader. 
 */

public struct Symbol
{
        char[]  name;           // Name of the exported procedure in dynamic library
        void**  pointer;        // Address of the procedure pointer variable
}

private import lib.paths;

/*
 * Linker : simple class to handle the loading 
 * of the library and exported functions
 */

//alias void function( char[] ) failureFN;

public class Linker
{

        private import std.stdio;
        
        const int RTLD_LAZY = 0x00001;          // Lazy function call binding
        const int RTLD_NOW  = 0x00002;          // Immediate function call binding
        const int RTLD_NOLOAD = 0x00004;    // No object load
        const int RTLD_DEEPBIND = 0x00008;  // 
        const int RTLD_GLOBAL = 0x00100;     // Make object available to whole program

        static char[][][char[]] loadFailures;
        
        /**
         * Gets all the failed loads for a specific library.
         * This is filled in only if the default onFailure method is used durin load
         * returns: An array of the names hat failed to load for a specific library
         *          or null if none was found
         */
        public static char[][] getLoadFailures(char[] libName)
        {
                if ( libName in loadFailures )
                {
                        return loadFailures[libName];
                }
                else
                {
                        return null;
                }
        }
        
        /**
         * Gets all libraries loaded.
         * This is filled in only if the default onFailure method is used durin load
         * returns: An array of the library names
         */
        public static char[][] getLoadLibraries()
        {
                return loadFailures.keys;
        }
        
        /**
         * Checks if any symbol failed to load
         * Returns: true is ALL symbols loaded
         */
        public static bool isPerfectLoad()
        {
                return loadFailures.keys.length == 0;
        }
        
        public static void dumpFailedLoads()
        {
                foreach ( char[] lib ; Linker.getLoadLibraries() )
                {
                        foreach ( char[] symbol ; Linker.getLoadFailures(lib) )
                        {
                                writefln("failed (%s) %s", lib, symbol);
                        }
                }
        }
        
        private HANDLE  handle;
        private HANDLE alternateHandle;
        
        private char[]  libraryName;
        private char[]  alternateLibraryName;

        // private bool continueOnFail = false;
        
        alias void function( char[] libraryName, char[] symbolName, char[] message=null) failureFN;
        
        private failureFN onLoadFailure;

        // -----------------------------------------------------

        this( char[] libraryName, char[] alternateLibraryName=null )
        {
                this(libraryName, alternateLibraryName, &(Linker.defaultFail));
        }
        
        // ---------------------------------------

        this (char[] libraryName, char[] alternateLibraryName, failureFN fn )
        {
                this.libraryName = libraryName;
                this.alternateLibraryName = alternateLibraryName;
                onLoadFailure = fn;

                version(Windows)
                {
                        handle = LoadLibraryA( this.libraryName ~ "\0" );
                        if ( alternateLibraryName !is null )
                        {
                                alternateHandle = LoadLibraryA( this.alternateLibraryName ~ "\0" );
                        }
                } 
                version(linux)
                {
                        handle = dlopen( (this.libraryName ~ "\0").ptr, RTLD_NOW);
                        if ( alternateLibraryName !is null )
                        {
                                alternateHandle = dlopen( (this.alternateLibraryName ~ "\0").ptr, RTLD_NOW);
                        }
                        // clear the error buffer
                        dlerror();
                }
                version(Darwin)
                {
                }
                else 
                {}
                        
                if (handle is null)
                {
                        throw new Exception("Library load failed: " ~ libraryName);
                }
                else
                {
                        writefln("Loaded lib = %s", libraryName);
                }

        }

        // ----------------------------------------
        
        ~this()
        {
                version(Windows) 
                {
                        // FreeLibrary(handle);
                }
                version(linux)
                {
                        // Linux version
                }
                version(Darwin)
                {
                }
                else
                {}
        }

        /**
         * Default on load fail.
         * Logs the symbols that failed to load
         */
        static void defaultFail( char[] libraryName, char[] symbolName, char[] message=null )
        {       
                //writefln("failed to load (%s): %s",libraryName , message );
                
                if ( !(libraryName in loadFailures) )
                {
                        char[][] cc;
                        loadFailures[libraryName] = cc;
                }
                
                loadFailures[libraryName] ~= symbolName.dup;    // need dup?
                
                //throw new Exception("Function failed to load from library: " ~ libraryName);
        }       

        /**
         * Loads all the simbols for this library
         * symbols: All the simbol names to be loaded
         */
        void link( inout Symbol[] symbols )
        {
                foreach( Symbol link; symbols ) 
                {
                        *link.pointer = getSymbol(handle, (link.name~"\0").ptr);
                        debug(loadSymbol) writefln("Loaded...", libraryName, " ", link.name);
                        if (*link.pointer is null)
                        {
                                // if gthread try on glib
                                if ( alternateHandle !is null )
                                {
                                        *link.pointer = getSymbol(alternateHandle, (link.name~"\0").ptr);
                                        writefln("Loader.Linker.link trying alternate lib <<<<<<<<< %s", link.name);
                                }
                                if (*link.pointer is null)
                                {
                                        onLoadFailure( libraryName, link.name );
                                }
                        }
                }
        }

}