Eliot Miranda uploaded a new version of FFI-Kernel to project FFI: http://source.squeak.org/FFI/FFI-Kernel.terf-eem.187.mcz
==================== Summary ====================
Name: FFI-Kernel.terf-eem.187 Author: eem Time: 2 August 2021, 11:15:30.36735 am UUID: 54737d19-448d-4377-859b-be958a51dec6 Ancestors: FFI-Kernel-eem.186
Performance: - cache an ExternalStructure class's externalType in a class inst var. - directly allocate an ExternalStructure[Type] using self byteSize rather than deferring to the externalType.
Minor: avoid variable shadowing warnings in compileStructureSpec:withAccessors:, compileTypeAliasSpec:withAccessors:, & maybeCompileAccessor:withSelector:.
=============== Diff against FFI-Kernel-eem.186 ===============
Item was changed: ----- Method: ExternalArrayType>>contentType (in category 'external data') ----- contentType "^ <ExternalType>" + "We are an array of things. Our content type is encoded in the compiledSpec's headerWord. The super implementation of #typeName can figure that out." + self flag: #contentVsContainer. "mt: For n-dimensional containers, we might have to adapt this." + ^ contentType ifNil: [contentType := ExternalType typeNamed: super typeName ]! - ^ contentType!
Item was changed: ExternalObject subclass: #ExternalStructure instanceVariableNames: '' classVariableNames: '' poolDictionaries: 'ExternalTypePool FFIConstants' category: 'FFI-Kernel'! ExternalStructure class + instanceVariableNames: 'compiledSpec byteAlignment externalType'! - instanceVariableNames: 'compiledSpec byteAlignment'!
!ExternalStructure commentStamp: 'eem 6/26/2019 15:26' prior: 0! An ExternalStructure is for representing external data that is - either a structure composed of different fields (a struct of C language) - or an alias for another type (like a typedef of C language)
It reserves enough bytes of data for representing all the fields.
The data is stored into the handle instance variable which can be of two different types: - ExternalAddress If the handle is an external address then the object described does not reside in the Smalltalk object memory. - ByteArray If the handle is a byte array then the object described resides in Smalltalk memory.
Instance Variables (class side) byteAlignment: <Integer> compiledSpec: <WordArray>
byteAlignment - the required alignment for the structure
compiledSpec - the bit-field definiton of the structure in the ExternalType encoding understood by the VM's FFI call marshalling machinery.
A specific structure is defined by subclassing ExternalStructure and specifying its #fields via a class side method. For example if we define a subclass: ExternalStructure subclass: #StructExample instanceVariableNames: '' classVariableNames: '' poolDictionaries: '' category: 'garbage'. Then declare the fields like this: StructExample class compile: 'fields ^#( (name ''char*'') (color ''ulong'') )' classified: 'garbage'.
It means that this type is composed of two different fields: - a string (accessed thru the field #name) - and an unsigned 32bit integer (accessed thru the field #color). It represents the following C type: struct StructExample {char *name; uint32_t color; };
The accessors for those fields can be generated automatically like this: StructExample defineFields. As can be verified in a Browser: StructExample browse. We see that name and color fields are stored sequentially in different zones of data.
The total size of the structure can be verified with: StructExample byteSize = (Smalltalk wordSize + 4).
An ExternalStructure can also be used for defining an alias. The fields definition must contain only 2 elements: an eventual accessor (or nil) and the type. For example, We can define a machine dependent 'unsigned long' like this: ExternalStructure subclass: #UnsignedLong instanceVariableNames: '' classVariableNames: '' poolDictionaries: '' category: 'garbage'. Then set the fields like this: UnsignedLong class compile: 'fields ^(Smalltalk wordSize=4 or: [Smalltalk platformName=''Win64'']) ifTrue: [#(nil ''ulong'')] ifFalse: [#(nil ''ulonglong'')]' classified: 'garbage'. And verify the size on current platform: UnsignedLong byteSize. Then, the class names 'UnsignedLong' and 'StructExamples' acts as a type specification. They can be used for composing other types, and for defining prototype of external functions:
LibraryExample>>initMyStruct: aStructExample name: name color: anInteger <cdecl: void 'init_my_struct'( StructExample * char * UnsignedLong )> self externalCallFailed
! ExternalStructure class + instanceVariableNames: 'compiledSpec byteAlignment externalType'! - instanceVariableNames: 'compiledSpec byteAlignment'!
Item was changed: ----- Method: ExternalStructure class>>allocate (in category 'instance creation') ----- allocate + ^ self fromHandle: (ByteArray new: self byteSize)! - - ^self externalType allocate!
Item was changed: ----- Method: ExternalStructure class>>compileStructureSpec:withAccessors: (in category 'field definition - support') ----- compileStructureSpec: specArray withAccessors: aSymbol "Compile a type specification for the FFI calls. Return the newly compiled spec. Eventually generate the field accessors according to following rules: - aSymbol = #always always generate the accessors - aSymbol = #never never generate the accessors - aSymbol = #generated only generate the auto-generated accessors - aSymbol = #absent only generate the absent accessors" | newByteAlignment byteOffset typeSpec newCompiledSpec | byteOffset := 0. newByteAlignment := self minStructureAlignment. typeSpec := WriteStream on: (WordArray new: 10). typeSpec nextPut: FFIFlagStructure. + specArray do: + [:spec | | fieldName fieldTypeName fieldType typeSize fieldAlignment | - specArray do: [:spec | - | fieldName fieldTypeName externalType typeSize fieldAlignment | fieldName := spec first. fieldTypeName := spec second. + fieldType := (ExternalType typeNamed: fieldTypeName) ifNil: [self errorTypeNotFound: spec second]. + typeSize := fieldType byteSize. + fieldAlignment := (fieldType byteAlignment max: self minFieldAlignment) min: self maxFieldAlignment. - externalType := (ExternalType typeNamed: fieldTypeName) - ifNil: [self errorTypeNotFound: spec second]. - typeSize := externalType byteSize. - fieldAlignment := (externalType byteAlignment - max: self minFieldAlignment) - min: self maxFieldAlignment. byteOffset := byteOffset alignedTo: fieldAlignment. newByteAlignment := newByteAlignment max: fieldAlignment. + spec size > 2 ifTrue: "extra size" + [spec third < typeSize - spec size > 2 ifTrue: ["extra size" - spec third < typeSize ifTrue: [^ self error: 'Explicit type size is less than expected']. + typeSize := spec third]. + (fieldName notNil and: [self shouldGenerate: fieldName policy: aSymbol]) ifTrue: + [self generateStructureFieldAccessorsFor: fieldName startingAt: byteOffset + 1 type: fieldType]. + typeSpec nextPutAll: (fieldType embeddedSpecWithSize: typeSize). + byteOffset := byteOffset + typeSize]. - typeSize := spec third. - ]. - (fieldName notNil and: [self shouldGenerate: fieldName policy: aSymbol]) ifTrue: [ - self generateStructureFieldAccessorsFor: fieldName startingAt: byteOffset + 1 type: externalType. - ]. - typeSpec nextPutAll: (externalType embeddedSpecWithSize: typeSize). - byteOffset := byteOffset + typeSize. - ]. newByteAlignment := newByteAlignment min: self maxStructureAlignment. byteOffset := byteOffset alignedTo: newByteAlignment. newCompiledSpec := typeSpec contents. newCompiledSpec at: 1 put: (byteOffset bitOr: FFIFlagStructure). self setCompiledSpec: newCompiledSpec + byteAlignment: newByteAlignment! - byteAlignment: newByteAlignment.!
Item was changed: ----- Method: ExternalStructure class>>compileTypeAliasSpec:withAccessors: (in category 'field definition - support') ----- compileTypeAliasSpec: spec withAccessors: aSymbol "Define all the fields in the receiver. Return the newly compiled spec." + | fieldName fieldTypeName fieldType | - | fieldName fieldTypeName externalType | fieldName := spec first. fieldTypeName := spec second. + fieldType := (ExternalType typeNamed: fieldTypeName) ifNil: [self errorTypeNotFound: spec second]. + (fieldName notNil and: [self shouldGenerate: fieldName policy: aSymbol]) ifTrue: + [self generateTypeAliasAccessorsFor: fieldName type: fieldType]. + fieldType isPointerType + ifTrue: "Special case. Typedef for a pointer type, e.g., typedef char* LPSTR in Win32 API. Mark it as both structure and pointer. Note that #isPointerType will only answer true for the in-image pointer type, not the non-pointer alias for the pointer." + [self - externalType := (ExternalType typeNamed: fieldTypeName) - ifNil: [self errorTypeNotFound: spec second]. - (fieldName notNil and:[self shouldGenerate: fieldName policy: aSymbol]) ifTrue:[ - self generateTypeAliasAccessorsFor: fieldName type: externalType]. - externalType isPointerType - ifTrue: ["Special case. Typedef for a pointer type, e.g., typedef char* LPSTR in Win32 API. Mark it as both structure and pointer. Note that #isPointerType will only answer true for the in-image pointer type, not the non-pointer alias for the pointer." - self setCompiledSpec: (WordArray with: ExternalType pointerAliasSpec) byteAlignment: ExternalType pointerAliasAlignment] + ifFalse: "Usual case. Typedef for another struct type or atomic type. Just re-use compiled spec and extras from the aliased type." + [self - ifFalse: ["Usual case. Typedef for another struct type or atomic type. Just re-use compiled spec and extras from the aliased type." - self flag: #isTypeAlias; + setCompiledSpec: fieldType compiledSpec + byteAlignment: fieldType byteAlignment]! - setCompiledSpec: externalType compiledSpec - byteAlignment: externalType byteAlignment].!
Item was changed: ----- Method: ExternalStructure class>>externalType (in category 'external type') ----- externalType "Return an external type describing the receiver as a structure" + ^externalType ifNil: [externalType := ExternalType structTypeNamed: self name]! - ^ExternalType structTypeNamed: self name!
Item was changed: ----- Method: ExternalStructure class>>maybeCompileAccessor:withSelector: (in category 'field definition - support') ----- maybeCompileAccessor: aString withSelector: selector "Only compile if category or source changed." + | theCategory ref | + theCategory := #'*autogenerated - accessing'. - | category ref | - category := #'*autogenerated - accessing'. ((ref := MethodReference class: self selector: selector) isValid + and: [ref sourceString = aString]) ifTrue: + [ref category ~= theCategory ifTrue: + [self organization classify: selector under: theCategory]. + ^self]. + self compile: aString classified: theCategory! - and: [ref category = category] - and: [ref sourceString = aString]) - ifTrue: [^ self]. - self compile: aString classified: category.!
Item was added: + ----- Method: ExternalStructureType>>allocate (in category 'external data') ----- + allocate + ^ referentClass fromHandle: (ByteArray new: self byteSize)!