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C API supports optional output args 

you can do stuff like

	int x;
	vips_min( fred, &min, "x", &x, NULL );

to get the x pos of the minimum
This commit is contained in:
John Cupitt 2011-09-05 18:16:32 +01:00
parent 18e2468c26
commit ad016c53a2
3 changed files with 206 additions and 110 deletions
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1
ChangeLog
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@ -7,6 +7,7 @@
- CLI supports optional output args
- in im_vips2tiff, enable YCbCr compression for jpeg write
- VipsMin stops search early if it can
- C API supports optional output args
10/8/11 started 7.26.3
- don't use G_VALUE_COLLECT_INIT(), many platforms do not have a glib this

10
TODO
View File

@ -1,13 +1,3 @@
- C interface needs to look for optional output args in final psss, eg.
vips_min( im, &min,
"x", &xpos,
"y", &ypos,
NULL );
- is our C API too awkward? we'll need
if( !(c = vips_add( a, b )) ||

305
libvips/iofuncs/operation.c
View File

@ -227,9 +227,52 @@ vips_operation_new( const char *name )
return( operation );
}
/* Some systems do not have va_copy() ... this might work (it does on MSVC),
* apparently.
*
* FIXME ... this should be in configure.in
*/
#ifndef va_copy
#define va_copy(d,s) ((d) = (s))
#endif
#define VIPS_OPERATION_COLLECT_SET( PSPEC, ARG_CLASS, AP ) \
if( (ARG_CLASS->flags & VIPS_ARGUMENT_INPUT) ) { \
GValue value = { 0, }; \
gchar *error = NULL; \
\
/* Input args are given inline, eg. ("factor", 12.0) \
* and must be collected. \
*/ \
g_value_init( &value, G_PARAM_SPEC_VALUE_TYPE( PSPEC ) ); \
G_VALUE_COLLECT( &value, AP, 0, &error ); \
\
/* Don't bother with the error message. \
*/ \
if( error ) { \
VIPS_DEBUG_MSG( "VIPS_OPERATION_COLLECT_SET: err\n" ); \
g_free( error ); \
}
#define VIPS_OPERATION_COLLECT_GET( PSPEC, ARG_CLASS, AP ) \
g_value_unset( &value ); \
} \
else if( (ARG_CLASS->flags & VIPS_ARGUMENT_OUTPUT) ) { \
void **arg; \
\
/* Output args are a pointer to where to send the \
* result. \
*/ \
arg = va_arg( AP, void ** );
#define VIPS_OPERATION_COLLECT_END \
}
static int
vips_operation_set_valist_required( VipsOperation *operation, va_list ap )
{
VIPS_DEBUG_MSG( "vips_operation_set_valist_required:\n" );
/* Set required input arguments. Can't use vips_argument_map here
* :-( because passing va_list by reference is not portable.
*/
@ -238,30 +281,8 @@ vips_operation_set_valist_required( VipsOperation *operation, va_list ap )
g_assert( argument_instance );
if( (argument_class->flags & VIPS_ARGUMENT_REQUIRED) &&
(argument_class->flags & VIPS_ARGUMENT_INPUT) &&
!argument_instance->assigned ) {
GValue value = { 0 };
char *msg = NULL;
/* It'd be nice to use G_VALUE_COLLECT_INIT(), but
* that's only available in very recent glib.
*/
g_value_init( &value,
G_PARAM_SPEC_VALUE_TYPE( pspec ) );
G_VALUE_COLLECT( &value, ap, 0, &msg );
if( msg ) {
VipsObjectClass *class =
VIPS_OBJECT_GET_CLASS( operation );
vips_error( class->description,
"%s", _( msg ) );
g_value_unset( &value );
g_free( msg );
return( -1 );
}
if( (argument_class->flags & VIPS_ARGUMENT_REQUIRED) ) {
VIPS_OPERATION_COLLECT_SET( pspec, argument_class, ap );
#ifdef VIPS_DEBUG
{
@ -276,23 +297,15 @@ vips_operation_set_valist_required( VipsOperation *operation, va_list ap )
g_object_set_property( G_OBJECT( operation ),
g_param_spec_get_name( pspec ), &value );
g_value_unset( &value );
}
else if( (argument_class->flags & VIPS_ARGUMENT_REQUIRED) &&
(argument_class->flags & VIPS_ARGUMENT_OUTPUT) &&
!argument_instance->assigned ) {
void *arg;
/* Output args are all pointers to places to write
* results. Skip here, we use these during the output
* phase.
*/
arg = va_arg( ap, void * );
VIPS_OPERATION_COLLECT_GET( pspec, argument_class, ap );
#ifdef VIPS_DEBUG
printf( "\tskipping arg %p for %s\n",
arg, g_param_spec_get_name( pspec ) );
#endif /*VIPS_DEBUG */
VIPS_OPERATION_COLLECT_END
}
} VIPS_ARGUMENT_FOR_ALL_END
@ -309,14 +322,16 @@ vips_operation_set_valist_optional( VipsOperation *operation, va_list ap )
char *name;
VIPS_DEBUG_MSG( "vips_operation_set_valist_optional:\n" );
name = va_arg( ap, char * );
while( name ) {
GValue value = { 0, };
GParamSpec *pspec;
gchar *error = NULL;
VipsArgumentClass *argument_class;
VIPS_DEBUG_MSG( "\tname = '%s' (%p)\n", name, name );
if( !(pspec = g_object_class_find_property(
G_OBJECT_CLASS( class ), name )) ) {
vips_error( VIPS_OBJECT_CLASS( class )->description,
@ -325,28 +340,18 @@ vips_operation_set_valist_optional( VipsOperation *operation, va_list ap )
return( -1 );
}
g_value_init( &value, G_PARAM_SPEC_VALUE_TYPE( pspec ) );
G_VALUE_COLLECT( &value, ap, 0, &error );
if( error ) {
vips_error( VIPS_OBJECT_CLASS( class )->description,
"%s", _( error ) );
g_value_unset( &value );
g_free( error );
return( -1 );
}
/* Only set input args, Output args are read from the
* finished object after build.
*/
argument_class = (VipsArgumentClass *)
vips__argument_table_lookup( argument_table, pspec );
if( argument_class &&
(argument_class->flags & VIPS_ARGUMENT_INPUT) )
if( argument_class ) {
VIPS_OPERATION_COLLECT_SET( pspec, argument_class, ap );
g_object_set_property( G_OBJECT( operation ),
name, &value );
g_value_unset( &value );
VIPS_OPERATION_COLLECT_GET( pspec, argument_class, ap );
VIPS_OPERATION_COLLECT_END
}
name = va_arg( ap, char * );
}
@ -354,35 +359,20 @@ vips_operation_set_valist_optional( VipsOperation *operation, va_list ap )
return( 0 );
}
static void
vips_operation_get_valist( VipsOperation *operation, va_list ap )
static int
vips_operation_get_valist_required( VipsOperation *operation, va_list ap )
{
VIPS_DEBUG_MSG( "vips_operation_get_valist_required:\n" );
/* Extract output arguments. Can't use vips_argument_map here
* :-( because passing va_list by reference is not portable.
*/
VIPS_ARGUMENT_FOR_ALL( operation,
pspec, argument_class, argument_instance ) {
if( (argument_class->flags & VIPS_ARGUMENT_REQUIRED) &&
(argument_class->flags & VIPS_ARGUMENT_INPUT) ) {
GValue value = { 0 };
char *msg = NULL;
if( (argument_class->flags & VIPS_ARGUMENT_REQUIRED) ) {
VIPS_OPERATION_COLLECT_SET( pspec, argument_class, ap );
/* Collect the arg from valist to eat it up, but don't
* do anything with it.
*
* It'd be nice to use G_VALUE_COLLECT_INIT(), but
* that's only available in very recent glib.
*/
g_value_init( &value,
G_PARAM_SPEC_VALUE_TYPE( pspec ) );
G_VALUE_COLLECT( &value, ap, 0, &msg );
g_value_unset( &value );
}
else if( (argument_class->flags & VIPS_ARGUMENT_REQUIRED) &&
(argument_class->flags & VIPS_ARGUMENT_OUTPUT) ) {
void **arg;
arg = va_arg( ap, void ** );
VIPS_OPERATION_COLLECT_GET( pspec, argument_class, ap );
if( !argument_instance->assigned )
continue;
@ -405,8 +395,113 @@ vips_operation_get_valist( VipsOperation *operation, va_list ap )
object = *((GObject **) arg);
g_object_unref( object );
}
VIPS_OPERATION_COLLECT_END
}
} VIPS_ARGUMENT_FOR_ALL_END
return( 0 );
}
static int
vips_operation_get_valist_optional( VipsOperation *operation, va_list ap )
{
VipsOperationClass *class =
VIPS_OPERATION_GET_CLASS( operation );
VipsArgumentTable *argument_table =
VIPS_OBJECT_CLASS( class )->argument_table;
char *name;
VIPS_DEBUG_MSG( "vips_operation_get_valist_optional:\n" );
name = va_arg( ap, char * );
while( name ) {
GParamSpec *pspec;
VipsArgumentClass *argument_class;
VIPS_DEBUG_MSG( "\tname = '%s' (%p)\n", name, name );
if( !(pspec = g_object_class_find_property(
G_OBJECT_CLASS( class ), name )) ) {
vips_error( VIPS_OBJECT_CLASS( class )->description,
_( "class `%s' has no property named `%s'\n" ),
G_OBJECT_TYPE_NAME( operation ), name );
return( -1 );
}
argument_class = (VipsArgumentClass *)
vips__argument_table_lookup( argument_table, pspec );
if( argument_class ) {
VIPS_OPERATION_COLLECT_SET( pspec, argument_class, ap );
g_object_set_property( G_OBJECT( operation ),
name, &value );
VIPS_OPERATION_COLLECT_GET( pspec, argument_class, ap );
#ifdef VIPS_DEBUG
printf( "\twriting %s to %p\n",
g_param_spec_get_name( pspec ), arg );
#endif /*VIPS_DEBUG */
g_object_get( G_OBJECT( operation ),
g_param_spec_get_name( pspec ), arg, NULL );
/* If the pspec is an object, that will up the ref
* count. We want to hand over the ref, so we have to
* knock it down again.
*/
if( G_IS_PARAM_SPEC_OBJECT( pspec ) ) {
GObject *object;
object = *((GObject **) arg);
g_object_unref( object );
}
VIPS_OPERATION_COLLECT_END
}
name = va_arg( ap, char * );
}
return( 0 );
}
static int
vips_call_required_optional( VipsOperation *operation,
va_list required, va_list optional )
{
int result;
va_list a;
va_list b;
/* We need to be able to walk required and optional twice. On x64 gcc,
* vips_operation_set_valist_required() etc. will destructively alter
* the pass-in va_list. We make a copy and walk that instead.
*/
va_copy( a, required );
va_copy( b, optional );
result = vips_operation_set_valist_required( operation, a ) ||
vips_operation_set_valist_optional( operation, b ) ||
vips_object_build( VIPS_OBJECT( operation ) );
va_end( a );
va_end( b );
if( result )
return( -1 );
/* Walk args again, writing output.
*/
va_copy( a, required );
va_copy( b, optional );
result = vips_operation_get_valist_required( operation, required ) ||
vips_operation_get_valist_optional( operation, optional );
va_end( a );
va_end( b );
return( result );
}
int
@ -414,8 +509,8 @@ vips_call( const char *operation_name, ... )
{
VipsOperation *operation;
int result;
va_list ap;
va_list required;
va_list optional;
VIPS_DEBUG_MSG( "vips_call: starting for %s ...\n", operation_name );
@ -427,13 +522,37 @@ vips_call( const char *operation_name, ... )
vips_object_print( VIPS_OBJECT( operation ) );
#endif /*VIPS_DEBUG*/
va_start( ap, operation_name );
result = vips_operation_set_valist_required( operation, ap ) ||
vips_operation_set_valist_optional( operation, ap ) ||
vips_object_build( VIPS_OBJECT( operation ) );
va_end( ap );
/* We have to break the va_list into separate required and optional
* components.
*
* Note the start, grab the required, then copy and reuse.
*/
va_start( required, operation_name );
/* Build failed: junk args and back out.
va_copy( optional, required );
VIPS_ARGUMENT_FOR_ALL( operation,
pspec, argument_class, argument_instance ) {
g_assert( argument_instance );
if( (argument_class->flags & VIPS_ARGUMENT_REQUIRED) ) {
VIPS_OPERATION_COLLECT_SET( pspec, argument_class,
optional );
VIPS_OPERATION_COLLECT_GET( pspec, argument_class,
optional );
VIPS_OPERATION_COLLECT_END
}
} VIPS_ARGUMENT_FOR_ALL_END
result = vips_call_required_optional( operation, required, optional );
va_end( required );
va_end( optional );
/* Failed: junk args and back out.
*/
if( result ) {
vips_argument_dispose_all( VIPS_OBJECT( operation ) );
@ -442,12 +561,6 @@ vips_call( const char *operation_name, ... )
return( -1 );
}
/* Walk args again writing output.
*/
va_start( ap, operation_name );
vips_operation_get_valist( operation, ap );
va_end( ap );
/* The operation we have built should now have been reffed by one of
* its arguments or have finished its work. Either way, we can unref.
*/
@ -464,7 +577,7 @@ vips_call_split( const char *operation_name, va_list optional, ... )
va_list required;
VIPS_DEBUG_MSG( "vips_call_split: starting for %s ...\n",
operation_name );
operation_name );
if( !(operation = vips_operation_new( operation_name ) ) )
return( -1 );
@ -475,9 +588,7 @@ vips_call_split( const char *operation_name, va_list optional, ... )
#endif /*VIPS_DEBUG*/
va_start( required, optional );
result = vips_operation_set_valist_required( operation, required ) ||
vips_operation_set_valist_optional( operation, optional ) ||
vips_object_build( VIPS_OBJECT( operation ) );
result = vips_call_required_optional( operation, required, optional );
va_end( required );
/* Build failed: junk args and back out.
@ -489,12 +600,6 @@ vips_call_split( const char *operation_name, va_list optional, ... )
return( -1 );
}
/* Walk args again writing output.
*/
va_start( required, optional );
vips_operation_get_valist( operation, required );
va_end( required );
/* The operation we have built should now have been reffed by one of
* its arguments or have finished its work. Either way, we can unref.
*/