main,bind,_examples: use absolute package imports and make configurable

This CL fixes an issue with the way python import statements are generated using an realtive current directory approach that is no longer compatible with python3. The default behavior has been updated to default to a dot-relative absolute package import for "go" and compiled extension, and a configuration option has been exposed from the CLI flags down to the bind package.
A refactor of configuration options was added to avoid further expanding the number of arguments being passed through the system.

Fixes #239

Author: justinfx

_examples/package/mypkg/mypkg.go

@@ -0,0 +1,10 @@
+// Copyright 2015 The go-python Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// mypkg is a nested package.
+package mypkg
+
+func SayHello() string {
+	return "Hello"
+}

_examples/package/mypkg/test.py

@@ -0,0 +1,12 @@
+# Copyright 2015 The go-python Authors.  All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+## py2/py3 compat
+from __future__ import absolute_import, print_function
+
+import mypkg.mypkg
+
+print("mypkg.mypkg.SayHello()...")
+print(mypkg.mypkg.SayHello())
+print("OK")

bind/bind.go

@@ -12,6 +12,22 @@ import (
 	"os"
 )
 
+// BindCfg is a configuration used during binding generation
+type BindCfg struct {
+	// output directory for bindings
+	OutputDir string
+	// name of output package (otherwise name of first package is used)
+	Name string
+	// code string to run in the go main() function in the cgo library
+	Main string
+	// the full command args as a string, without path to exe
+	Cmd string
+	// path to python interpreter
+	VM string
+	// package prefix used when generating python import statements
+	PkgPrefix string
+}
+
 // ErrorList is a list of errors
 type ErrorList []error
 

bind/gen.go

@@ -229,15 +229,15 @@ import os,sys,inspect,collections
 cwd = os.getcwd()
 currentdir = os.path.dirname(os.path.abspath(inspect.getfile(inspect.currentframe())))
 os.chdir(currentdir)
-import _%[1]s
+%[6]s
 os.chdir(cwd)
 
 # to use this code in your end-user python file, import it as follows:
 # from %[1]s import %[3]s
 # and then refer to everything using %[3]s. prefix
 # packages imported by this package listed below:
 
-%[6]s
+%[7]s
 
 `
 
@@ -249,14 +249,15 @@ os.chdir(cwd)
 # File is generated by gopy. Do not edit.
 # %[2]s
 
-import _%[1]s, collections
+import collections
+%[6]s
 
 # to use this code in your end-user python file, import it as follows:
 # from %[1]s import %[3]s
 # and then refer to everything using %[3]s. prefix
 # packages imported by this package listed below:
 
-%[6]s
+%[7]s
 
 `
 
@@ -463,15 +464,11 @@ var NoMake = false
 // and wrapper .py file(s) that are loaded as the interface to the package with shadow
 // python-side classes
 // mode = gen, build, pkg, exe
-func GenPyBind(mode BuildMode, odir, outname, cmdstr, vm, mainstr, libext, extragccargs string, lang int) error {
+func GenPyBind(mode BuildMode, libext, extragccargs string, lang int, cfg *BindCfg) error {
 	gen := &pyGen{
 		mode:         mode,
-		odir:         odir,
-		pypkgname:    outname,
-		outname:      outname,
-		cmdstr:       cmdstr,
-		vm:           vm,
-		mainstr:      mainstr,
+		pypkgname:    cfg.Name,
+		cfg:          cfg,
 		libext:       libext,
 		extraGccArgs: extragccargs,
 		lang:         lang,
@@ -497,22 +494,17 @@ type pyGen struct {
 	err    ErrorList
 	pkgmap map[string]struct{} // map of package paths
 
-	mode      BuildMode // mode: gen, build, pkg, exe
-	odir      string    // output directory
-	pypkgname string    // python package name, for pkg and exe build modes (--name arg there), else = outname
-	// all global functions in goPreamble are accessed by: pypkgname.FuncName, e.g., IncRef, DecRef
-	outname      string // output (package) name -- for specific current go package
-	cmdstr       string // overall command (embedded in generated files)
-	vm           string // python interpreter
-	mainstr      string // main function code string
+	mode         BuildMode // mode: gen, build, pkg, exe
+	pypkgname    string
+	cfg          *BindCfg
 	libext       string
 	extraGccArgs string
 	lang         int // c-python api version (2,3)
 }
 
 func (g *pyGen) gen() error {
 	g.pkg = nil
-	err := os.MkdirAll(g.odir, 0755)
+	err := os.MkdirAll(g.cfg.OutputDir, 0755)
 	if err != nil {
 		return fmt.Errorf("gopy: could not create output directory: %v", err)
 	}
@@ -549,14 +541,14 @@ func (g *pyGen) genPre() {
 	if !NoMake {
 		g.genMakefile()
 	}
-	oinit, err := os.Create(filepath.Join(g.odir, "__init__.py"))
+	oinit, err := os.Create(filepath.Join(g.cfg.OutputDir, "__init__.py"))
 	g.err.Add(err)
 	err = oinit.Close()
 	g.err.Add(err)
 }
 
 func (g *pyGen) genPrintOut(outfn string, pr *printer) {
-	of, err := os.Create(filepath.Join(g.odir, outfn))
+	of, err := os.Create(filepath.Join(g.cfg.OutputDir, outfn))
 	g.err.Add(err)
 	_, err = io.Copy(of, pr)
 	g.err.Add(err)
@@ -565,10 +557,10 @@ func (g *pyGen) genPrintOut(outfn string, pr *printer) {
 }
 
 func (g *pyGen) genOut() {
-	g.pybuild.Printf("\nmod.generate(open('%v.c', 'w'))\n\n", g.outname)
+	g.pybuild.Printf("\nmod.generate(open('%v.c', 'w'))\n\n", g.cfg.Name)
 	g.gofile.Printf("\n\n")
 	g.genLeaksPostamble()
-	g.genPrintOut(g.outname+".go", g.gofile)
+	g.genPrintOut(g.cfg.Name+".go", g.gofile)
 	g.genPrintOut("patch-leaks.go", g.leakfile)
 	g.genPrintOut("build.py", g.pybuild)
 	if !NoMake {
@@ -585,7 +577,7 @@ func (g *pyGen) genPkgWrapOut() {
 		if g.mode == ModeGen || g.mode == ModeBuild {
 			impstr += fmt.Sprintf("import %s\n", im)
 		} else {
-			impstr += fmt.Sprintf("from %s import %s\n", g.outname, im)
+			impstr += fmt.Sprintf("from %s import %s\n", g.cfg.Name, im)
 		}
 	}
 	b := g.pywrap.buf.Bytes()
@@ -615,7 +607,7 @@ func (g *pyGen) genGoPreamble() {
 		pkgimport += fmt.Sprintf("\n\t%q", pi)
 	}
 	libcfg := func() string {
-		pycfg, err := GetPythonConfig(g.vm)
+		pycfg, err := GetPythonConfig(g.cfg.VM)
 		if err != nil {
 			panic(err)
 		}
@@ -629,29 +621,30 @@ func (g *pyGen) genGoPreamble() {
 		return pkgcfg
 	}()
 
-	if g.mode == ModeExe && g.mainstr == "" {
-		g.mainstr = "GoPyMainRun()" // default is just to run main
+	if g.mode == ModeExe && g.cfg.Main == "" {
+		g.cfg.Main = "GoPyMainRun()" // default is just to run main
 	}
 	exeprec := ""
 	exeprego := ""
 	if g.mode == ModeExe {
-		exeprec = fmt.Sprintf(goExePreambleC, g.outname)
+		exeprec = fmt.Sprintf(goExePreambleC, g.cfg.Name)
 		exeprego = goExePreambleGo
 	}
-	g.gofile.Printf(goPreamble, g.outname, g.cmdstr, libcfg, GoHandle, CGoHandle, pkgimport, g.mainstr, exeprec, exeprego)
-	g.gofile.Printf("\n// --- generated code for package: %[1]s below: ---\n\n", g.outname)
+	g.gofile.Printf(goPreamble, g.cfg.Name, g.cfg.Cmd, libcfg, GoHandle, CGoHandle,
+		pkgimport, g.cfg.Main, exeprec, exeprego)
+	g.gofile.Printf("\n// --- generated code for package: %[1]s below: ---\n\n", g.cfg.Name)
 }
 
 func (g *pyGen) genLeaksPreamble() {
-	g.leakfile.Printf(patchLeaksPreamble, g.outname, g.cmdstr)
+	g.leakfile.Printf(patchLeaksPreamble, g.cfg.Name, g.cfg.Cmd)
 }
 
 func (g *pyGen) genLeaksPostamble() {
 	g.leakfile.Printf(patchLeaksPostamble)
 }
 
 func (g *pyGen) genPyBuildPreamble() {
-	g.pybuild.Printf(PyBuildPreamble, g.outname, g.cmdstr)
+	g.pybuild.Printf(PyBuildPreamble, g.cfg.Name, g.cfg.Cmd)
 }
 
 func (g *pyGen) genPyWrapPreamble() {
@@ -666,14 +659,34 @@ func (g *pyGen) genPyWrapPreamble() {
 	}
 
 	// import other packages for other types that we might use
-	impstr := ""
+	var impstr, impgenstr string
+	impgenNames := []string{"_" + g.cfg.Name, "go"}
 	switch {
 	case g.pkg.Name() == "go":
-		impstr += fmt.Sprintf(GoPkgDefs, g.outname)
+		if g.cfg.PkgPrefix != "" {
+			impgenstr += fmt.Sprintf("from %s import %s\n", g.cfg.PkgPrefix, "_"+g.cfg.Name)
+		} else {
+			impgenstr += fmt.Sprintf("import %s\n", "_"+g.cfg.Name)
+		}
+		impstr += fmt.Sprintf(GoPkgDefs, g.cfg.Name)
 	case g.mode == ModeGen || g.mode == ModeBuild:
-		impstr += fmt.Sprintf("import go\n")
+		if g.cfg.PkgPrefix != "" {
+			for _, name := range impgenNames {
+				impgenstr += fmt.Sprintf("from %s import %s\n", g.cfg.PkgPrefix, name)
+			}
+		} else {
+			for _, name := range impgenNames {
+				impgenstr += fmt.Sprintf("import %s\n", name)
+			}
+		}
 	default:
-		impstr += fmt.Sprintf("from %s import go\n", g.outname)
+		pkg := "." + g.cfg.Name
+		if g.cfg.PkgPrefix != "" {
+			pkg = g.cfg.PkgPrefix + pkg
+		}
+		for _, name := range impgenNames {
+			impgenstr += fmt.Sprintf("from %s import %s\n", pkg, name)
+		}
 	}
 	imps := g.pkg.pkg.Imports()
 	for _, im := range imps {
@@ -685,9 +698,9 @@ func (g *pyGen) genPyWrapPreamble() {
 	impstr += importHereKeyString
 
 	if g.mode == ModeExe {
-		g.pywrap.Printf(PyWrapExePreamble, g.outname, g.cmdstr, n, pkgimport, pkgDoc, impstr)
+		g.pywrap.Printf(PyWrapExePreamble, g.cfg.Name, g.cfg.Cmd, n, pkgimport, pkgDoc, impgenstr, impstr)
 	} else {
-		g.pywrap.Printf(PyWrapPreamble, g.outname, g.cmdstr, n, pkgimport, pkgDoc, impstr)
+		g.pywrap.Printf(PyWrapPreamble, g.cfg.Name, g.cfg.Cmd, n, pkgimport, pkgDoc, impgenstr, impstr)
 	}
 }
 
@@ -708,18 +721,18 @@ func CmdStrToMakefile(cmdstr string) string {
 }
 
 func (g *pyGen) genMakefile() {
-	gencmd := strings.Replace(g.cmdstr, "gopy build", "gopy gen", 1)
+	gencmd := strings.Replace(g.cfg.Cmd, "gopy build", "gopy gen", 1)
 	gencmd = CmdStrToMakefile(gencmd)
 
-	pycfg, err := GetPythonConfig(g.vm)
+	pycfg, err := GetPythonConfig(g.cfg.VM)
 	if err != nil {
 		panic(err)
 	}
 
 	if g.mode == ModeExe {
-		g.makefile.Printf(MakefileExeTemplate, g.outname, g.cmdstr, gencmd, g.vm, g.libext, pycfg.CFlags, pycfg.LdFlags)
+		g.makefile.Printf(MakefileExeTemplate, g.cfg.Name, g.cfg.Cmd, gencmd, g.cfg.VM, g.libext, pycfg.CFlags, pycfg.LdFlags)
 	} else {
-		g.makefile.Printf(MakefileTemplate, g.outname, g.cmdstr, gencmd, g.vm, g.libext, g.extraGccArgs, pycfg.CFlags, pycfg.LdFlags)
+		g.makefile.Printf(MakefileTemplate, g.cfg.Name, g.cfg.Cmd, gencmd, g.cfg.VM, g.libext, g.extraGccArgs, pycfg.CFlags, pycfg.LdFlags)
 	}
 }
 

bind/gen_func.go

@@ -240,7 +240,7 @@ func (g *pyGen) genFuncBody(sym *symbol, fsym *Func) {
 		}
 	}
 
-	pkgname := g.outname
+	pkgname := g.cfg.Name
 
 	_, gdoc, _ := extractPythonName(fsym.GoName(), fsym.Doc())
 	ifchandle, gdoc := isIfaceHandle(gdoc)

bind/gen_map.go

@@ -61,7 +61,7 @@ class %[2]s(%[5]sGoClass):
 }
 
 func (g *pyGen) genMapInit(slc *symbol, extTypes, pyWrapOnly bool, mpob *Map) {
-	pkgname := g.outname
+	pkgname := g.cfg.Name
 	slNm := slc.id
 	qNm := pkgname + "." + slNm
 	typ := slc.GoType().Underlying().(*types.Map)

bind/gen_slice.go

@@ -62,7 +62,7 @@ class %[2]s(%[5]sGoClass):
 func (g *pyGen) genSliceInit(slc *symbol, extTypes, pyWrapOnly bool, slob *Slice) {
 	pkgname := slc.gopkg.Name()
 	slNm := slc.id
-	qNm := g.outname + "." + slNm // this is only for referring to the _ .go package!
+	qNm := g.cfg.Name + "." + slNm // this is only for referring to the _ .go package!
 	var esym *symbol
 	if typ, ok := slc.GoType().Underlying().(*types.Slice); ok {
 		esym = current.symtype(typ.Elem())

bind/gen_struct.go

@@ -36,7 +36,7 @@ class %[1]s(%[4]s):
 }
 
 func (g *pyGen) genStructInit(s *Struct) {
-	pkgname := g.outname
+	pkgname := g.cfg.Name
 	qNm := s.GoName()
 	// strNm := s.obj.Name()
 
@@ -176,7 +176,7 @@ func (g *pyGen) genStructMembers(s *Struct) {
 }
 
 func (g *pyGen) genStructMemberGetter(s *Struct, i int, f types.Object) {
-	pkgname := g.outname
+	pkgname := g.cfg.Name
 	ft := f.Type()
 	ret := current.symtype(ft)
 	if ret == nil {
@@ -217,7 +217,7 @@ func (g *pyGen) genStructMemberGetter(s *Struct, i int, f types.Object) {
 }
 
 func (g *pyGen) genStructMemberSetter(s *Struct, i int, f types.Object) {
-	pkgname := g.outname
+	pkgname := g.cfg.Name
 	ft := f.Type()
 	ret := current.symtype(ft)
 	if ret == nil {

bind/gen_varconst.go

@@ -34,7 +34,7 @@ func (g *pyGen) genVar(v *Var) {
 
 func (g *pyGen) genVarGetter(v *Var) {
 	gopkg := g.pkg.Name()
-	pkgname := g.outname
+	pkgname := g.cfg.Name
 	cgoFn := v.Name() // plain name is the getter
 	qCgoFn := gopkg + "_" + cgoFn
 	qFn := "_" + pkgname + "." + qCgoFn
@@ -74,7 +74,7 @@ func (g *pyGen) genVarGetter(v *Var) {
 
 func (g *pyGen) genVarSetter(v *Var) {
 	gopkg := g.pkg.Name()
-	pkgname := g.outname
+	pkgname := g.cfg.Name
 	cgoFn := fmt.Sprintf("Set_%s", v.Name())
 	qCgoFn := gopkg + "_" + cgoFn
 	qFn := "_" + pkgname + "." + qCgoFn