Documentation
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Index ¶
- func BlockSigName(objcType string, m *typemap.Mapper) string
- func EmitBSDPackage(w io.Writer) error
- func EmitBlocks(w io.Writer, framework *macosplatformmetadata.FrameworkMeta, m *typemap.Mapper, ...) error
- func EmitBridge(outDir string, framework *macosplatformmetadata.FrameworkMeta, ...) error
- func EmitBridgeHeader(w io.Writer, framework *macosplatformmetadata.FrameworkMeta, m *typemap.Mapper, ...) error
- func EmitBridgeImpl(w io.Writer, framework *macosplatformmetadata.FrameworkMeta, m *typemap.Mapper, ...) error
- func EmitClass(w io.Writer, name string, cls macosplatformmetadata.Class, ...) error
- func EmitClassInterfaces(w io.Writer, pkgName string, framework *macosplatformmetadata.FrameworkMeta, ...) error
- func EmitClasses(outDir string, framework *macosplatformmetadata.FrameworkMeta, ...) error
- func EmitEnums(w io.Writer, framework *macosplatformmetadata.FrameworkMeta) error
- func EmitExterns(w io.Writer, pkgName string, framework *macosplatformmetadata.FrameworkMeta, ...) error
- func EmitFoundationVariadicWrappers(w io.Writer, pkgName string) error
- func EmitFunctions(w io.Writer, pkgName, packageName string, ...) error
- func EmitGeneratedBridgesImpl(outDir, packageName string) error
- func EmitProtocolImpls(outDir string, framework *macosplatformmetadata.FrameworkMeta, ...) error
- func EmitProtocolProxies(w io.Writer, pkgName, packageName string, ...) error
- func EmitProtocols(w io.Writer, pkgName string, framework *macosplatformmetadata.FrameworkMeta, ...) error
- func EmitRuntimeBlocksGo(w io.Writer, sigs []BlockSignatureModel, pkg string) error
- func EmitRuntimeBlocksTrampolineHeader(w io.Writer, sigs []BlockSignatureModel) error
- func EmitRuntimeBlocksTrampolineImpl(w io.Writer, sigs []BlockSignatureModel) error
- func EmitRuntimeCallbacksGo(w io.Writer, sigs []MethodSigModel, pkg string) error
- func EmitRuntimeCallbacksTrampolineHeader(w io.Writer, sigs []MethodSigModel) error
- func EmitRuntimeCallbacksTrampolineImpl(w io.Writer, sigs []MethodSigModel) error
- func EmitStructs(w io.Writer, framework *macosplatformmetadata.FrameworkMeta, m *typemap.Mapper, ...) (typemap.ImportSet, error)
- func EmitSubclassFactories(outDir string, framework *macosplatformmetadata.FrameworkMeta, ...) error
- func EnumsNeedImports(framework *macosplatformmetadata.FrameworkMeta) (needsFmt, needsStrings bool)
- type BlockSigArg
- type BlockSignatureModel
- type MethodSigArg
- type MethodSigModel
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func BlockSigName ¶
BlockSigName returns the canonical C-safe name for an ObjC block type string. Two ObjC block types that share the same primitive C representation produce the same name (e.g. "void (^)(id)" and "void (^)(NSError *)" both → "void_ptr"). Returns "" when the block type cannot be parsed.
func EmitBSDPackage ¶
EmitBSDPackage writes the static bsd support package source. The type mapper resolves POSIX/BSD C structs (see typemap's bsdStructTypes) to bsd.TypeName references, so the package must exist alongside the generated C library packages. Because the libraries output tree is wiped on every run, the package is re-emitted by the generator rather than hand-crafted.
func EmitBlocks ¶
func EmitBlocks(w io.Writer, framework *macosplatformmetadata.FrameworkMeta, m *typemap.Mapper, knownClasses map[string]bool) error
EmitBlocks writes named Go func types for each unique ObjC block signature collected by the scanner.
func EmitBridge ¶
func EmitBridge(outDir string, framework *macosplatformmetadata.FrameworkMeta, m *typemap.Mapper, knownClasses map[string]bool) error
Bridge generates the C bridge header (.h) and ObjC implementation (.m) for a framework, writing both into outDir/bridge/, plus a thin shim .m file in outDir (the package root) that #includes the bridge implementation so that CGo auto-compiles it. (CGo only auto-compiles .m files in the package root, not in subdirectories.)
Why we generate C bridge functions rather than calling ObjC methods directly:
CGo only understands C calling conventions — it cannot express Objective-C message sends ([object method]) at all. The ObjC methods already exist on macOS, compiled into the framework dylibs, but the only way Go can invoke them is through a plain C function. Each generated bridge function:
- Accepts CGo-compatible parameters (void* for ObjC objects, scalar types)
- Casts them back to ObjC types and sends the message
- Retains the result with [retain] before returning (see memory model below)
- Returns a C-compatible value
No method logic is reimplemented; the bridge is purely a calling-convention adapter. The alternative — using objc_msgSend directly — is fragile: the cast of the function pointer varies by return type and architecture. The generated wrapper approach is far more robust.
Memory model for returned ObjC objects (non-ARC):
All bridge .m files are compiled with -fno-objc-arc. In non-ARC code, __bridge_retained is a no-op (equivalent to __bridge). Returned ObjC objects would be autoreleased by the @autoreleasepool block and freed before the Go caller could use them. To match Go's finalizer model, every bridge function that returns an ObjC object calls [_result retain] before returning. The Go wrapper calls runtime.Track to register a CFRelease finalizer, which releases that +1 retain when the Go GC collects the wrapper.
Why some methods are skipped (marked Unavailable in metadata):
A small number of SDK classes mark their -init and +new methods with __attribute__((unavailable)) / NS_UNAVAILABLE. This is a hard Clang compile-time error, not a runtime version guard. These are factory-only classes (e.g. NSCollectionLayoutDimension, WKWebExtensionAction) where Apple's design explicitly forbids bare initialisation; callers must use the class factory methods. Generating call sites for unavailable methods would produce code that does not compile. Skipping them honours the SDK's explicit design intent.
func EmitBridgeHeader ¶
func EmitBridgeHeader(w io.Writer, framework *macosplatformmetadata.FrameworkMeta, m *typemap.Mapper, knownClasses map[string]bool) error
BridgeHeader writes the C bridge header (.h) to w.
func EmitBridgeImpl ¶
func EmitBridgeImpl(w io.Writer, framework *macosplatformmetadata.FrameworkMeta, m *typemap.Mapper, knownClasses map[string]bool, headerName string) error
BridgeImpl writes the ObjC bridge implementation (.m) to w.
func EmitClass ¶
func EmitClass(w io.Writer, name string, cls macosplatformmetadata.Class, framework *macosplatformmetadata.FrameworkMeta, m *typemap.Mapper, knownClasses map[string]bool, allClasses map[string]macosplatformmetadata.Class, packageName string) error
WriteClass writes a single ObjC class as a Go source file using struct embedding for inheritance. Root classes (no superclass or unknown superclass) retain a plain `ptr unsafe.Pointer` field. Non-root classes embed their immediate superclass by value; Go's method promotion gives access to all ancestor methods.
func EmitClassInterfaces ¶
func EmitClassInterfaces(w io.Writer, pkgName string, framework *macosplatformmetadata.FrameworkMeta, m *typemap.Mapper, knownClasses map[string]bool, allClasses map[string]macosplatformmetadata.Class) error
EmitClassInterfaces writes one [ClassName]able interface per concrete ObjC class, modelled on the Kiota [Type]able pattern. Each interface lists all instance methods with identical signatures to those emitted on *ClassName, enabling mock implementations for testing and polymorphic acceptance of compatible types.
Generic classes (e.g. NSArray[T]) are skipped in this pass — their interface signatures require type parameters that complicate the embedding chain.
func EmitClasses ¶
func EmitClasses(outDir string, framework *macosplatformmetadata.FrameworkMeta, m *typemap.Mapper, knownClasses map[string]bool, allClasses map[string]macosplatformmetadata.Class, packageName string) error
Classes writes one Go source file per ObjC class into outDir. allClasses is the combined class map from all frameworks, used for building cross-framework embedding chains and constructors.
func EmitEnums ¶
func EmitEnums(w io.Writer, framework *macosplatformmetadata.FrameworkMeta) error
Enums writes all enum types and their constants to w.
func EmitExterns ¶
func EmitExterns(w io.Writer, pkgName string, framework *macosplatformmetadata.FrameworkMeta, m *typemap.Mapper, knownClasses map[string]bool) error
Externs writes a complete _externs.go file for the framework's extern symbols.
func EmitFoundationVariadicWrappers ¶
EmitFoundationVariadicWrappers writes convenience variadic constructors for the most commonly used Foundation collection classes (NSArray, NSMutableArray, NSSet, NSMutableSet, NSDictionary, NSMutableDictionary). The underlying ObjC nil-terminated variadics (+arrayWithObjects:, +dictionaryWithObjectsAndKeys:, etc.) are not bridgeable via CGo; these wrappers use either:
- A pure-Go path via existing non-variadic bridged methods (NSArray, NSSet),
- An embedded C helper (non-variadic wrapper) per the CGo pattern for functions that have no suitable non-variadic ObjC equivalent (NSDictionary).
The generated file is written only for the Foundation framework.
func EmitFunctions ¶
func EmitFunctions(w io.Writer, pkgName, packageName string, framework *macosplatformmetadata.FrameworkMeta, m *typemap.Mapper, knownClasses map[string]bool) error
Functions writes a complete _functions.go file for the framework's plain C functions.
func EmitGeneratedBridgesImpl ¶
EmitGeneratedBridgesImpl writes {packageName}_impl.m at outDir — a CGo-compiled aggregate that #includes all *_subclass.m and *_impl.m files from bridge/. Without this file the ObjC symbols defined in those bridge files would not be linked. If no generated bridge files exist the file is not written.
func EmitProtocolImpls ¶
func EmitProtocolImpls(outDir string, framework *macosplatformmetadata.FrameworkMeta, m *typemap.Mapper) error
EmitProtocolImpls writes per-protocol callback files for all protocols in framework.
For each protocol NSFooDelegate it writes:
- outDir/NSFooDelegate_protocol_callback.go — NSFooDelegateCallbacks struct + NewNSFooDelegateProtocolCallback
- outDir/bridge/NSFooDelegate_protocol_callback.h
- outDir/bridge/NSFooDelegate_protocol_callback.m
func EmitProtocolProxies ¶
func EmitProtocolProxies(w io.Writer, pkgName, packageName string, framework *macosplatformmetadata.FrameworkMeta, m *typemap.Mapper, knownClasses map[string]bool, allClasses map[string]macosplatformmetadata.Class) error
ProtocolProxies writes a Go source file containing concrete id<Protocol> wrapper types for each ObjC protocol in the framework that appears in a return position.
The name reflects the ObjC id<Protocol> concept: each type is named <GoProtoName>IDProtocol (e.g. VZVirtualMachineDelegateIDProtocol for id<VZVirtualMachineDelegate>). The type:
- Embeds foundation.NSObject, satisfying cgo.Object and NSObjectProtocol
- Exports a New<Name> constructor that registers a GC finalizer via cgo.Track
- Implements all non-variadic protocol methods via CGo bridge calls that cast the receiver to id<Protocol> and dispatch dynamically
func EmitProtocols ¶
func EmitProtocols(w io.Writer, pkgName string, framework *macosplatformmetadata.FrameworkMeta, m *typemap.Mapper, knownClasses map[string]bool, knownProtocols map[string]string, allClasses map[string]macosplatformmetadata.Class) error
Protocols writes a complete _protocols.go file with Go interface definitions for all ObjC protocols in the framework.
func EmitRuntimeBlocksGo ¶
func EmitRuntimeBlocksGo(w io.Writer, sigs []BlockSignatureModel, pkg string) error
EmitRuntimeBlocksGo writes the generated runtime/blocks_generated.go file. This file contains //export goCallBlock_* callbacks and MakeBlock_* factories.
func EmitRuntimeBlocksTrampolineHeader ¶
func EmitRuntimeBlocksTrampolineHeader(w io.Writer, sigs []BlockSignatureModel) error
EmitRuntimeBlocksTrampolineHeader writes runtime/block_trampolines_generated.h.
func EmitRuntimeBlocksTrampolineImpl ¶
func EmitRuntimeBlocksTrampolineImpl(w io.Writer, sigs []BlockSignatureModel) error
EmitRuntimeBlocksTrampolineImpl writes runtime/block_trampolines_generated.m.
func EmitRuntimeCallbacksGo ¶
func EmitRuntimeCallbacksGo(w io.Writer, sigs []MethodSigModel, pkg string) error
EmitRuntimeCallbacksGo writes callbacks_generated.go for the bindings/runtime/callbacks package.
func EmitRuntimeCallbacksTrampolineHeader ¶
func EmitRuntimeCallbacksTrampolineHeader(w io.Writer, sigs []MethodSigModel) error
EmitRuntimeCallbacksTrampolineHeader writes method_trampolines_generated.h.
func EmitRuntimeCallbacksTrampolineImpl ¶
func EmitRuntimeCallbacksTrampolineImpl(w io.Writer, sigs []MethodSigModel) error
EmitRuntimeCallbacksTrampolineImpl writes method_trampolines_generated.m.
func EmitStructs ¶
func EmitStructs(w io.Writer, framework *macosplatformmetadata.FrameworkMeta, m *typemap.Mapper, knownClasses map[string]bool) (typemap.ImportSet, error)
Structs writes all C struct type definitions and struct typedef aliases to w. It returns a map of Go package alias → import path for any cross-framework imports required by struct fields (e.g. corefoundation for CF-typed fields).
func EmitSubclassFactories ¶
func EmitSubclassFactories(outDir string, framework *macosplatformmetadata.FrameworkMeta, m *typemap.Mapper, superIndex map[string]bool, allClasses map[string]macosplatformmetadata.Class) error
EmitSubclassFactories writes per-class subclass factory files for all classes in framework that appear in superIndex (i.e. classes that Apple itself subclasses).
For each eligible class NSFoo it writes:
- outDir/NSFoo_subclass.go — NSFooOverrides struct + NewNSFooSubclass factory
- outDir/bridge/NSFoo_subclass.h — C declarations
- outDir/bridge/NSFoo_subclass.m — ObjC alloc+class_addMethod+BindCallback
func EnumsNeedImports ¶
func EnumsNeedImports(framework *macosplatformmetadata.FrameworkMeta) (needsFmt, needsStrings bool)
EnumsNeedImports reports which stdlib imports the enum file will need.
Types ¶
type BlockSigArg ¶
type BlockSigArg struct {
CType string // C type in the trampoline: "void *", "int64_t", "bool"
CGOType string // CGo type in the //export function: "unsafe.Pointer", "C.int64_t"
GoType string // Go type in MakeBlock factory: "unsafe.Pointer", "int64", "bool"
}
BlockSigArg describes a single argument in a BlockSignatureModel.
type BlockSignatureModel ¶
type BlockSignatureModel struct {
Name string // canonical C-safe name: "void_ptr_ptr", "int64_ptr_ptr"
IsVoidRet bool // true when block returns void
RetC string // C return type: "int64_t", "bool", "" for void
RetCGo string // CGo type in //export: "C.int64_t", "C.bool", "" for void
RetGo string // Go return type: "int64", "bool", "" for void
Args []BlockSigArg
}
BlockSignatureModel describes a unique primitive-typed block signature. Two ObjC block types that differ only in ObjC object types (e.g. id vs NSString *) produce the same BlockSignatureModel because they share the same C/Go representation.
func BlockSigFromObjC ¶
func BlockSigFromObjC(objcType string, m *typemap.Mapper) (BlockSignatureModel, bool)
BlockSigFromObjC builds a BlockSignatureModel from an ObjC block type string. Returns the zero value and false if the type cannot be parsed.
func CollectBlockSignaturesFromFrameworks ¶
func CollectBlockSignaturesFromFrameworks(frameworks []*macosplatformmetadata.FrameworkMeta, m *typemap.Mapper) []BlockSignatureModel
CollectBlockSignaturesFromFrameworks scans all methods/protocols/extensions in the provided list of framework metas and returns the deduplicated, sorted set of BlockSignatures that need Go trampolines.
type MethodSigArg ¶
type MethodSigArg struct {
CType string // C type in the trampoline: "void *", "int64_t", "bool"
CGOType string // CGo type in the //export function
GoType string // Go type in the callback func
Enc string // ObjC type encoding character(s)
}
MethodSigArg describes one explicit argument (not self or _cmd).
type MethodSigModel ¶
type MethodSigModel struct {
Name string // "void_ptr_ptr" — retToken[_argToken...] (no self token)
IsVoidRet bool
CReturnType string // C return type: "void", "int64_t", "bool"
CGoReturnType string // CGo type: "C.int64_t", "C.bool", "" for void
GoReturnType string // Go return type: "int64", "bool", "" for void
Params []MethodSigArg
ObjCEnc string // ObjC type encoding for class_addMethod: "v@:@"
}
MethodSigModel describes a unique primitive-typed IMP method signature. Two ObjC methods that differ only in ObjC object types share the same MethodSigModel because they use the same C/Go representation.
Unlike block signatures, self (id) is always implicit — it is NOT reflected in the Name tokens. The Go callback ALWAYS receives self as its first arg.
func CollectMethodSigsFromFrameworks ¶
func CollectMethodSigsFromFrameworks(frameworks []*macosplatformmetadata.FrameworkMeta, m *typemap.Mapper) []MethodSigModel
CollectMethodSigsFromFrameworks scans all class and protocol methods in frameworks and returns the deduplicated, sorted set of MethodSigs that need IMP trampolines. Methods with struct-by-value arguments/returns are excluded (not IMP-safe).
Source Files