From 2c401de4f4ce03a7d17c727101f6d506abd80514 Mon Sep 17 00:00:00 2001 From: David Chisnall Date: Sun, 27 Dec 2009 13:54:51 +0000 Subject: [PATCH] Added GSBlocks header. This defines two macros: DEFINE_BLOCK_TYPE() defines a new block type. CALL_BLOCK() calls a block. These use the compiler's native support for blocks if it exists, but otherwise implement the lower-level version. Note that the structure defined by the fall-back versions is NOT a complete definition of the block layout, and copies of this structure should never be instantiated. This does not allow non-blocks-aware compiles (like GCC) to create blocks, but it does allow them to use blocks. This means that we can implement things like NSArray's -enumerateObjectsUsingBlock: without breaking GCC compatibility. To do so, you'd first need to declare a block type in the header, like this: DEFINE_BLOCK_TYPE(GSEnumeratorBlock, void, id, NSUInteger, BOOL*); Then declare the method like this: - (void)enumerateObjectsUsingBlock: (GSEnumeratorBlock)aBlock; Finally, implement it like this: - (void)enumerateObjectsUsingBlock: (GSEnumeratorBlock)aBlock { NSUInteger count = 0; BOOL shouldStop = NO; for (obj in self) { CALL_BLOCK(aBlock, obj, count++, &shouldStop); if (shouldStop) { return; } } } If you compile this with clang -fblocks then it will work using Clang's native support for blocks. If you compile it with GCC or clang without -fblocks then it will use the other version. Note that this example uses fast enumeration, so will only compile with clang. A proper GNUstep implementation should have some fall-back code for primitive compilers that don't support this either. git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/base/trunk@29169 72102866-910b-0410-8b05-ffd578937521 --- ChangeLog | 4 +++ Headers/Additions/GNUstepBase/GSBlocks.h | 32 ++++++++++++++++++++++++ 2 files changed, 36 insertions(+) create mode 100644 Headers/Additions/GNUstepBase/GSBlocks.h diff --git a/ChangeLog b/ChangeLog index 4bf985c49..704639f26 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,7 @@ +2009-12-27 David Chisnall + + * Headers/Additions/GNUstepBase/GSBlocks.h: Added block macros. + 2009-12-23 Wolfgang Lux * Source/NSUndoManager.m (_canCoalesceUndoWithTarget:selector:object): diff --git a/Headers/Additions/GNUstepBase/GSBlocks.h b/Headers/Additions/GNUstepBase/GSBlocks.h new file mode 100644 index 000000000..a9532771b --- /dev/null +++ b/Headers/Additions/GNUstepBase/GSBlocks.h @@ -0,0 +1,32 @@ + +/* Define the has_feature pseudo-macro for GCC. */ +#ifndef __has_feature +#define __has_feature(x) 0 +#endif + +#if __has_feature(blocks) +/** + * Defines a block type. Will work whether or not the compiler natively + * supports blocks. + */ +#define DEFINE_BLOCK_TYPE(name, retTy, argTys, ...) \ +typedef retTy(^name)(argTys, ## __VA_ARGS__) +/** + * Calls a block. Works irrespective of whether the compiler supports blocks. + */ +#define CALL_BLOCK(block, args, ...) \ + block(args, ## __VA_ARGS__) +/* Fall-back versions for when the compiler doesn't have native blocks support. + */ +#else +#define DEFINE_BLOCK_TYPE(name, retTy, argTys, ...) \ + typedef struct {\ + void *isa;\ + int flags;\ + int reserved;\ + retTy (*invoke)(void*, argTys, ## __VA_ARGS__);\ + } *name +#define CALL_BLOCK(block, args, ...) \ + block->invoke(block, args, ## __VA_ARGS__) +#endif +