Package com.jogamp.common.os

Class NativeLibrary

  • All Implemented Interfaces:
    DynamicLookupHelper
    public final class NativeLibrary
extends Object
implements DynamicLookupHelper
    Provides low-level, relatively platform-independent access to shared ("native") libraries. The core library routines System.load() and System.loadLibrary() in general provide suitable functionality for applications using native code, but are not flexible enough to support certain kinds of glue code generation and deployment strategies. This class supports direct linking of native libraries to other shared objects not necessarily installed on the system (in particular, via the use of dlopen(RTLD_GLOBAL) on Unix platforms) as well as manual lookup of function names to support e.g. GlueGen's ProcAddressTable glue code generation style without additional supporting code needed in the generated library.

    • Method Detail

      • getSystemEnvLibraryPathVarname

        public static final String getSystemEnvLibraryPathVarname()
        Returns the system's environment variable name used for the dynamic linker to resolve library locations, e.g. - Windows: PATH - MacOS: DYLD_LIBRARY_PATH - Unix: LD_LIBRARY_PATH

      • open

        public static final NativeLibrary open​(String libName,
                                       boolean searchSystemPath,
                                       boolean searchSystemPathFirst,
                                       ClassLoader loader,
                                       boolean global)
                                throws SecurityException
        Opens the given native library, assuming it has the same base name on all platforms.

        The searchSystemPath argument changes the behavior to either use the default system path or not at all.

        Assuming searchSystemPath is true, the searchSystemPathFirst argument changes the behavior to first search the default system path rather than searching it last.

        Parameters:
        libName - library name, with or without prefix and suffix
        searchSystemPath - if true library shall be searched in the system path (default), otherwise false.
        searchSystemPathFirst - if true system path shall be searched first (default), rather than searching it last. if searchSystemPath is false this argument is ignored.
        loader - ClassLoader to locate the library
        global - if true allows system wide access of the loaded library, otherwise access is restricted to the process.
        Returns:
        NativeLibrary instance or null if library could not be loaded.
        Throws:
        SecurityException - if user is not granted access for the named library.
        Since:
        2.4.0

      • open

        public static final NativeLibrary open​(String windowsLibName,
                                       String unixLibName,
                                       String macOSXLibName,
                                       boolean searchSystemPath,
                                       boolean searchSystemPathFirst,
                                       ClassLoader loader,
                                       boolean global)
                                throws SecurityException
        Opens the given native library, assuming it has the given base names (no "lib" prefix or ".dll/.so/.dylib" suffix) on the Windows, Unix and Mac OS X platforms, respectively, and in the context of the specified ClassLoader, which is used to help find the library in the case of e.g. Java Web Start.

        The searchSystemPath argument changes the behavior to either use the default system path or not at all.

        Assuming searchSystemPath is true, the searchSystemPathFirst argument changes the behavior to first search the default system path rather than searching it last.

        Note that we do not currently handle DSO versioning on Unix. Experience with JOAL and OpenAL has shown that it is extremely problematic to rely on a specific .so version (for one thing, ClassLoader.findLibrary on Unix doesn't work with files not ending in .so, for example .so.0), and in general if this dynamic loading facility is used correctly the version number will be irrelevant.
        Parameters:
        windowsLibName - windows library name, with or without prefix and suffix
        unixLibName - unix library name, with or without prefix and suffix
        macOSXLibName - mac-osx library name, with or without prefix and suffix
        searchSystemPath - if true library shall be searched in the system path (default), otherwise false.
        searchSystemPathFirst - if true system path shall be searched first (default), rather than searching it last. if searchSystemPath is false this argument is ignored.
        loader - ClassLoader to locate the library
        global - if true allows system wide access of the loaded library, otherwise access is restricted to the process.
        Returns:
        NativeLibrary instance or null if library could not be loaded.
        Throws:
        SecurityException - if user is not granted access for the named library.

      • dynamicLookupFunctionGlobal

        public final long dynamicLookupFunctionGlobal​(String funcName)
                                       throws SecurityException
        Looks up the given function name in all loaded libraries.
        Throws:
        SecurityException - if user is not granted access for the named library.

      • getLibraryHandle

        public final long getLibraryHandle()
        Retrieves the low-level library handle from this NativeLibrary object. On the Windows platform this is an HMODULE, and on Unix and Mac OS X platforms the void* result of calling dlopen().

      • getLibraryPath

        public final String getLibraryPath()
        Retrieves the path under which this library was opened.

      • close

        public final void close()
                 throws SecurityException
        Closes this native library. Further lookup operations are not allowed after calling this method.
        Throws:
        SecurityException - if user is not granted access for the named library.

      • isValidNativeLibraryName

        public static final String isValidNativeLibraryName​(String libName,
                                                    boolean isLowerCaseAlready)
        Comparison of prefix and suffix of the given libName's basename is performed case insensitive
        Parameters:
        libName - the full path library name with prefix and suffix
        isLowerCaseAlready - indicates if libName is already lower-case
        Returns:
        basename of libName w/o path, ie. /usr/lib/libDrinkBeer.so -> DrinkBeer on Unix systems, but null on Windows.

      • enumerateLibraryPaths

        public static final List<String> enumerateLibraryPaths​(String windowsLibName,
                                                       String unixLibName,
                                                       String macOSXLibName,
                                                       ClassLoader loader)
        Given the base library names (no prefixes/suffixes) for the various platforms, enumerate the possible locations and names of the indicated native library on the system not using the system path.

      • enumerateLibraryPaths

        public static final List<String> enumerateLibraryPaths​(String windowsLibName,
                                                       String unixLibName,
                                                       String macOSXLibName,
                                                       boolean searchSystemPathFirst,
                                                       ClassLoader loader)
        Given the base library names (no prefixes/suffixes) for the various platforms, enumerate the possible locations and names of the indicated native library on the system using the system path.