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 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

 /* This Source Code Form is subject to the terms of the Mozilla Public

  * License, v. 2.0. If a copy of the MPL was not distributed with this

  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

 #ifndef prlink_h___

 #define prlink_h___

 /*

 ** API to static and dynamic linking.

 */

 #include "prtypes.h"

 PR_BEGIN_EXTERN_C

 typedef struct PRLibrary PRLibrary;

 typedef struct PRStaticLinkTable {

     const char *name;

     void (*fp)(void);

 } PRStaticLinkTable;

 /*

 ** Change the default library path to the given string. The string is

 ** copied. This call will fail if it runs out of memory.

 **

 ** The string provided as 'path' is copied. The caller can do whatever is

 ** convenient with the argument when the function is complete.

 */

 NSPR_API(PRStatus) PR_SetLibraryPath(const char *path);

 /*

 ** Return a character string which contains the path used to search for

 ** dynamically loadable libraries.

 **

 ** The returned value is basically a copy of a PR_SetLibraryPath().

 ** The storage is allocated by the runtime and becomes the responsibilty

 ** of the caller.

 */

 NSPR_API(char*) PR_GetLibraryPath(void);

 /*

 ** Given a directory name "dir" and a library name "lib" construct a full

 ** path name that will refer to the actual dynamically loaded

 ** library. This does not test for existance of said file, it just

 ** constructs the full filename. The name constructed is system dependent

 ** and prepared for PR_LoadLibrary. The result must be free'd when the

 ** caller is done with it.

 **

 ** The storage for the result is allocated by the runtime and becomes the

 ** responsibility of the caller.

 */

 NSPR_API(char*) PR_GetLibraryName(const char *dir, const char *lib);

 /*

 **

 ** Free the memory allocated, for the caller, by PR_GetLibraryName

 */

 NSPR_API(void) PR_FreeLibraryName(char *mem);

 /*

 ** Given a library "name" try to load the library. The argument "name"

 ** is a machine-dependent name for the library, such as the full pathname

 ** returned by PR_GetLibraryName.  If the library is already loaded,

 ** this function will avoid loading the library twice.

 **

 ** If the library is loaded successfully, then a pointer to the PRLibrary

 ** structure representing the library is returned.  Otherwise, NULL is

 ** returned.

 **

 ** This increments the reference count of the library.

 */

 NSPR_API(PRLibrary*) PR_LoadLibrary(const char *name);

 /*

 ** Each operating system has its preferred way of specifying

 ** a file in the file system.  Most operating systems use

 ** a pathname.  Mac OS Classic, on the other hand, uses the FSSpec

 ** structure to specify a file. PRLibSpec allows NSPR clients

 ** to use the type of file specification that is most efficient

 ** for a particular platform.

 **

 ** On some operating systems such as Mac OS Classic, a shared library

 ** may contain code fragments that can be individually loaded.

 ** PRLibSpec also allows NSPR clients to identify a code fragment

 ** in a library, if code fragments are supported by the OS.

 ** A code fragment can be specified by name or by an integer index.

 **

 ** Right now PRLibSpec supports four types of library specification:

 ** a pathname in the native character encoding, a Mac code fragment

 ** by name, a Mac code fragment by index, and a UTF-16 pathname.

 */

 typedef enum PRLibSpecType {

     PR_LibSpec_Pathname,

     PR_LibSpec_MacNamedFragment,   /* obsolete (for Mac OS Classic) */

     PR_LibSpec_MacIndexedFragment, /* obsolete (for Mac OS Classic) */

     PR_LibSpec_PathnameU           /* supported only on Win32 */ 

 } PRLibSpecType;

 struct FSSpec; /* Mac OS Classic FSSpec */

 typedef struct PRLibSpec {

     PRLibSpecType type;

     union {

         /* if type is PR_LibSpec_Pathname */

         const char *pathname;

         /* if type is PR_LibSpec_MacNamedFragment */

         struct {

             const struct FSSpec *fsspec;

             const char *name;

         } mac_named_fragment;      /* obsolete (for Mac OS Classic) */

         /* if type is PR_LibSpec_MacIndexedFragment */

         struct {

             const struct FSSpec *fsspec;

             PRUint32 index;

         } mac_indexed_fragment;    /* obsolete (for Mac OS Classic) */

         /* if type is PR_LibSpec_PathnameU */

         const PRUnichar *pathname_u; /* supported only on Win32 */

     } value;

 } PRLibSpec;

 /*

 ** The following bit flags may be or'd together and passed

 ** as the 'flags' argument to PR_LoadLibraryWithFlags.

 ** Flags not supported by the underlying OS are ignored.

 */

 #define PR_LD_LAZY   0x1  /* equivalent to RTLD_LAZY on Unix */

 #define PR_LD_NOW    0x2  /* equivalent to RTLD_NOW on Unix */

 #define PR_LD_GLOBAL 0x4  /* equivalent to RTLD_GLOBAL on Unix */

 #define PR_LD_LOCAL  0x8  /* equivalent to RTLD_LOCAL on Unix */

 /* The following is equivalent to LOAD_WITH_ALTERED_SEARCH_PATH on Windows */

 #define PR_LD_ALT_SEARCH_PATH  0x10  

 /*                0x8000     reserved for NSPR internal use */

 /*

 ** Load the specified library, in the manner specified by 'flags'.

 */

 NSPR_API(PRLibrary *)

 PR_LoadLibraryWithFlags(

     PRLibSpec libSpec,    /* the shared library */

     PRIntn flags          /* flags that affect the loading */

 );

 /*

 ** Unload a previously loaded library. If the library was a static

 ** library then the static link table will no longer be referenced. The

 ** associated PRLibrary object is freed.

 **

 ** PR_FAILURE is returned if the library cannot be unloaded.

 **

 ** This function decrements the reference count of the library.

 */

 NSPR_API(PRStatus) PR_UnloadLibrary(PRLibrary *lib);

 /*

 ** Given the name of a procedure, return the address of the function that

 ** implements the procedure, or NULL if no such function can be

 ** found. This does not find symbols in the main program (the ".exe");

 ** use PR_LoadStaticLibrary to register symbols in the main program.

 **

 ** This function does not modify the reference count of the library.

 */

 NSPR_API(void*) PR_FindSymbol(PRLibrary *lib, const char *name);

 /*

 ** Similar to PR_FindSymbol, except that the return value is a pointer to

 ** a function, and not a pointer to void. Casting between a data pointer

 ** and a function pointer is not portable according to the C standard.

 ** Any function pointer can be cast to any other function pointer.

 **

 ** This function does not modify the reference count of the library.

 */

 typedef void (*PRFuncPtr)(void);

 NSPR_API(PRFuncPtr) PR_FindFunctionSymbol(PRLibrary *lib, const char *name);

 /*

 ** Finds a symbol in one of the currently loaded libraries. Given the

 ** name of a procedure, return the address of the function that

 ** implements the procedure, and return the library that contains that

 ** symbol, or NULL if no such function can be found. This does not find

 ** symbols in the main program (the ".exe"); use PR_AddStaticLibrary to

 ** register symbols in the main program.  

 **

 ** This increments the reference count of the library.

 */

 NSPR_API(void*) PR_FindSymbolAndLibrary(const char *name,

 						      PRLibrary* *lib);

 /*

 ** Similar to PR_FindSymbolAndLibrary, except that the return value is

 ** a pointer to a function, and not a pointer to void. Casting between a

 ** data pointer and a function pointer is not portable according to the C

 ** standard. Any function pointer can be cast to any other function pointer.

 **

 ** This increments the reference count of the library.

 */

 NSPR_API(PRFuncPtr) PR_FindFunctionSymbolAndLibrary(const char *name,

 						      PRLibrary* *lib);

 /*

 ** Register a static link table with the runtime under the name

 ** "name". The symbols present in the static link table will be made

 ** available to PR_FindSymbol. If "name" is null then the symbols will be

 ** made available to the library which represents the executable. The

 ** tables are not copied.

 **

 ** Returns the library object if successful, null otherwise.

 **

 ** This increments the reference count of the library.

 */

 NSPR_API(PRLibrary*) PR_LoadStaticLibrary(

     const char *name, const PRStaticLinkTable *table);

 /*

 ** Return the pathname of the file that the library "name" was loaded

 ** from. "addr" is the address of a function defined in the library.

 **

 ** The caller is responsible for freeing the result with PR_Free.

 */

 NSPR_API(char *) PR_GetLibraryFilePathname(const char *name, PRFuncPtr addr);

 PR_END_EXTERN_C

 #endif /* prlink_h___ */