dispatch/dispatch.py

##########################################################################
#
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"""Generate DLL/SO dispatching functions.
""" 


# Adjust path
import os.path
import sys
sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..'))


import specs.stdapi as stdapi


def function_pointer_type(function):
    return 'PFN_' + function.name.upper()


def function_pointer_value(function):
    return '_' + function.name + '_ptr'


class Dispatcher:

    def header(self):
        pass

    def dispatchModule(self, module):
        for function in module.functions:
            self.dispatchFunction(module, function)
        
        # define standard name aliases for convenience, but only when not
        # tracing, as that would cause symbol clashing with the tracing
        # functions
        print '#ifdef RETRACE'
        for function in module.functions:
            print '#define %s _%s' % (function.name, function.name)
        print '#endif /* RETRACE */'
        print

    def dispatchFunction(self, module, function):
        ptype = function_pointer_type(function)
        pvalue = function_pointer_value(function)
        print 'typedef ' + function.prototype('* %s' % ptype) + ';'
        print 'static %s %s = NULL;' % (ptype, pvalue)
        print
        print 'static inline ' + function.prototype('_' + function.name) + ' {'
        print '    const char *_name = "%s";' % function.name
        if function.type is stdapi.Void:
            ret = ''
        else:
            ret = 'return '
        self.invokeGetProcAddress(module, function)
        print '    %s%s(%s);' % (ret, pvalue, ', '.join([str(arg.name) for arg in function.args]))
        print '}'
        print

    def getProcAddressName(self, module, function):
        raise NotImplementedError

    def invokeGetProcAddress(self, module, function):
        ptype = function_pointer_type(function)
        pvalue = function_pointer_value(function)
        getProcAddressName = self.getProcAddressName(module, function)
        print '    if (!%s) {' % (pvalue,)
        print '        %s = (%s)%s(_name);' % (pvalue, ptype, getProcAddressName)
        print '        if (!%s) {' % (pvalue,)
        self.failFunction(function)
        print '        }'
        print '    }'

    def failFunction(self, function):
        if function.type is stdapi.Void or function.fail is not None:
            print r'            os::log("warning: ignoring call to unavailable function %s\n", _name);'
            if function.type is stdapi.Void:
                assert function.fail is None
                print '            return;' 
            else:
                assert function.fail is not None
                print '            return %s;' % function.fail
        else:
            print r'            os::log("error: unavailable function %s\n", _name);'
            print r'            os::abort();'