images: 针对cgo生成一些图片

images/Makefile

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+# Copyright 2017 <chaishushan{AT}gmail.com>. All rights reserved.
+# Use of this source code is governed by a Apache
+# license that can be found in the LICENSE file.
+
+UML_FILES=$(wildcard ./*.plantuml)
+UML_SVG_FILES=$(patsubst %.plantuml,%.uml.svg,$(UML_FILES))
+UML_PNG_FILES=$(patsubst %.plantuml,%.uml.png,$(UML_FILES))
+
+DOT_FILES=$(wildcard ./*.dot)
+DOT_PNG_FILES=$(patsubst %.dot,%.dot.png,$(DOT_FILES))
+
+default: $(UML_PNG_FILES) $(DOT_PNG_FILES)
+	@echo "ok"
+
+logo:
+	convert logo-2018-01.png -resize 300x65 logo.png
+	@echo "ok"
+
+clean:
+	-rm *.dot.png
+	-rm *.uml.png
+	-rm *.uml.svg
+
+%.uml.svg: %.plantuml
+	cat $< | docker run --rm -i chai2010/ibox:plantuml >  $@
+
+%.uml.png: %.plantuml
+	cat $< | docker run --rm -i chai2010/ibox:plantuml -tpng >  $@
+
+%.dot.png: %.dot
+	dot -Tpng -o $@ $<

images/ch2-call-c-sum-v1.plantuml

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+' Copyright 2017 <chaishushan{AT}gmail.com>. All rights reserved.
+' Use of this source code is governed by a Apache
+' license that can be found in the LICENSE file.
+
+@startuml
+
+title C.sum(2, 3)
+
+|main.go|
+:func main() {
+	C.sum(2, 3))
+};
+
+|#AntiqueWhite|main.cgo1.go|
+:func main() {
+	_Cfunc_sum(2, 3))
+};
+
+|#AntiqueWhite|_cgo_types.go|
+:func _Cfunc_sum(2, 3) double {
+	_cgo_runtime_cgocall(...)
+	return
+};
+
+|runtime.cgocall|
+:_cgo_runtime_cgocall(...);
+
+fork
+
+|#AntiqueWhite|main.cgo2.c|
+: double _cgo_xxx_Cfunc_sum(2, 3) {
+	return sum(2, 3)
+};
+
+|#AntiqueWhite|_cgo_export.c|
+:sum(2, 3);
+
+endfork
+
+|runtime.cgocall|
+:_cgo_runtime_cgocall(...);
+
+|main.go|
+stop
+
+@enduml

images/ch2-call-c-sum-v2.plantuml

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+' Copyright 2017 <chaishushan{AT}gmail.com>. All rights reserved.
+' Use of this source code is governed by a Apache
+' license that can be found in the LICENSE file.
+
+@startuml
+
+title c call go func
+
+|_testmain.c|
+:int main() {
+	extern int sum(int a, int b)
+	sum(1, 2)
+	return 0
+};
+-[#green,dashed]->
+
+fork
+
+|#AntiqueWhite|_cgo_export.c|
+:int sum(int p0, int p1) {
+	struct { int p0, p1, r0; } a
+	_cgo_ctxt = _cgo_wait_runtime_init_done()
+	crosscall2(_cgoexp_xxx_sum, &a, 16, _cgo_ctxt)
+	_cgo_release_context(_cgo_ctxt)
+	return a.r0
+};
+
+|runtime/cgo/*.asm|
+:TEXT crosscall2(SB),NOSPLIT,$0;
+
+fork
+
+|#AntiqueWhite|_cgo_types.go|
+:func _cgoexp_xxx_sum(a unsafe.Pointer, n int32, ctxt uintptr) {
+	fn := _cgoexpwrap_xxx_sum
+	_cgo_runtime_cgocallback(
+		_cgoexpwrap_xxx_sum,
+		...
+	)
+};
+
+|#AntiqueWhite|_cgo_types.go|
+:func _cgoexpwrap_xxx_sum(p0, p1) r0 {
+	return sum(p0, p1)
+};
+
+|main.go|
+://export sum
+func sum(a, b C.int) C.int {
+	return a + b
+};
+
+endfork
+
+|runtime/cgo/*.asm|
+:TEXT crosscall2(SB),NOSPLIT,$0;
+
+endfork
+
+|_testmain.c|
+stop
+
+@enduml

images/ch2-cgo-generated-files.dot

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+// Copyright 2018 <chaishushan{AT}gmail.com>. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+digraph G {
+	subgraph cluster_cgo_package_main {
+		label = "package main";
+
+		nocgo_x[label="nocgo_x.go", style=filled, color=gray];
+		hello_go[label="hello.go", style=filled, color=orangered4];
+		main_go[label="main.go", style=filled, color=darkgreen];
+		nocgo_1[label="nocgo_1.go", style=filled, color=gray];
+	}
+
+	subgraph cluster_cgo_generated_files {
+		label = "cgo: generated fileds";
+
+		main_cgo2_c[label="main.cgo2.c", style=filled, color=green];
+		main_cgo1_go[label="main.cgo1.go", style=filled, color=green];
+
+		hello_cgo2_c[label="hello.cgo2.c", style=filled, color=red];
+		hello_cgo1_go[label="hello.cgo1.go", style=filled, color=red];
+
+		_cgo_gotypes_go[label="_cgo_gotypes.go", shape=box, style=filled, color=dodgerblue];
+		_cgo_export_h[label="_cgo_export.h", shape=box, style=filled, color=dodgerblue];
+		_cgo_export_c[label="_cgo_export.c", shape=box, style=filled, color=dodgerblue];
+
+		main_go -> main_cgo1_go -> _cgo_gotypes_go;
+		main_go -> main_cgo2_c -> _cgo_gotypes_go;
+
+		hello_go -> hello_cgo1_go -> _cgo_gotypes_go;
+		hello_go -> hello_cgo2_c -> _cgo_gotypes_go;
+
+		_cgo_gotypes_go -> _cgo_export_h;
+		_cgo_gotypes_go -> _cgo_export_c;
+	}
+}

images/ch2-int32-to-char-ptr.plantuml

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+' Copyright 2017 <chaishushan{AT}gmail.com>. All rights reserved.
+' Use of this source code is governed by a Apache
+' license that can be found in the LICENSE file.
+
+@startuml
+
+title int32 <=> *C.char
+
+participant int32
+participant uintptr
+participant unsafe.Pointer as unsafe_Pointer
+participant "~*C.char" as c_char_ptr
+
+== Go ==
+
+int32 -> uintptr: int32 to uintptr
+uintptr -> unsafe_Pointer: uintptr to unsafe.Pointer
+
+== CGO ==
+
+unsafe_Pointer -> c_char_ptr: unsafe.Pointer to *C.char
+c_char_ptr -> unsafe_Pointer: ~*C.char to unsafe.Pointer
+
+== Go ==
+
+unsafe_Pointer -> uintptr: unsafe.Pointer to uintptr
+uintptr -> int32: uintptr to int32
+
+@enduml

images/ch2-qsort-v2.plantuml

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+' Copyright 2017 <chaishushan{AT}gmail.com>. All rights reserved.
+' Use of this source code is governed by a Apache
+' license that can be found in the LICENSE file.
+
+@startuml
+
+title qsort
+
+participant go
+participant c
+
+[--> go: qsort
+activate go
+
+go -> go
+activate go #DarkSalmon
+note left
+	go_qsort_compare_info.elemsize = sv.Type().Elem().Size()
+	go_qsort_compare_info.fn = fn
+end note
+
+deactivate go
+
+go -> c: C.qsort_proxy(cmp=go_qsort_compare)
+activate c
+note right
+void qsort_proxy(
+	void* base, size_t num, size_t size,
+	int (*compare)(const void* a, const void* b)
+) {
+	go_qsort_compare_save_base(base);
+	qsort(base, num, size, compare);
+}
+end note
+
+' begin
+	c -> c: C.go_qsort_compare_save_base
+	activate c #DarkSalmon
+	note right: callback go func
+
+	go <- c: go_qsort_compare_save_base
+	activate go #DarkSalmon
+	note left
+		//export go_qsort_compare_save_base
+		func go_qsort_compare_save_base(base unsafe.Pointer) {
+			go_qsort_compare_info.base = uintptr(base)
+		}
+		var go_qsort_compare_info struct {
+			base     uintptr
+			elemsize uintptr
+			fn       func(a, b int) int
+			sync.RWMutex
+		}
+	end note
+
+	go -> c: go_qsort_compare_save_base done
+	deactivate go
+
+	deactivate c
+' end
+
+loop
+	c -> c: C.go_qsort_compare
+	activate c #DarkSalmon
+	note right: callback go func
+
+	c -> go: go_qsort_compare
+	activate go #DarkSalmon
+	note left
+		//export go_qsort_compare_save_base
+		func go_qsort_compare_save_base(base unsafe.Pointer) {
+			go_qsort_compare_info.base = uintptr(base)
+		}
+	end note
+
+	go -> c: go_qsort_compare done
+	deactivate go
+
+	deactivate c
+end
+
+go <- c: C.qsort_proxy done
+deactivate c
+
+[<-- go: done
+deactivate go
+
+@enduml

images/ch2-x-ptr-to-y-ptr.plantuml

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+' Copyright 2017 <chaishushan{AT}gmail.com>. All rights reserved.
+' Use of this source code is governed by a Apache
+' license that can be found in the LICENSE file.
+
+@startuml
+
+title *X <=> *Y
+
+participant "~*X" as x_ptr
+participant unsafe.Pointer as unsafe_Pointer
+participant "~*Y" as y_ptr
+
+== *X => *Y ==
+
+x_ptr -> unsafe_Pointer: ~*X to unsafe.Pointer
+unsafe_Pointer -> y_ptr: unsafe.Pointer to *Y
+
+== *Y => *X ==
+
+y_ptr -> unsafe_Pointer: ~*Y to unsafe.Pointer
+unsafe_Pointer -> x_ptr: unsafe.Pointer to *X
+
+@enduml

images/ch2-x-slice-to-y-slice.plantuml

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+' Copyright 2017 <chaishushan{AT}gmail.com>. All rights reserved.
+' Use of this source code is governed by a Apache
+' license that can be found in the LICENSE file.
+
+
+'var p []X
+'var q []Y // q = p
+
+'pHdr := (*reflect.SliceHeader)(unsafe.Pointer(&p))
+'qHdr := (*reflect.SliceHeader)(unsafe.Pointer(&q))
+
+'pHdr.Data = qHdr.Data
+'pHdr.Len = qHdr.Len * unsafe.Sizeof(q[0]) / unsafe.Sizeof(p[0])
+'pHdr.Cap = qHdr.Cap * unsafe.Sizeof(q[0]) / unsafe.Sizeof(p[0])
+
+
+@startuml
+
+title []X <=> []Y
+
+participant "var x []X\nvar y []Y" as slice
+participant "var px *SliceHeader\nvar py *SliceHeader" as slice_header
+
+== []X and []Y to *reflect.SliceHeader  ==
+
+slice -> slice_header: px := (*reflect.SliceHeader)(unsafe.Pointer(&x))\npy := (*reflect.SliceHeader)(unsafe.Pointer(&y))
+
+== copy *px to *py ==
+
+slice_header -> slice_header: ~*py = *px
+
+== y changed by *py ==
+
+slice -> slice: y = x
+
+@enduml