Adds ImportName, ImportAlias

dave · Mar 9, 2018 · 010a36a · 010a36a
1 parent 585b61e
commit 010a36a
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Showing 7 changed files with 519 additions and 46 deletions.
diff --git a/README.md b/README.md
@@ -24,7 +24,7 @@ Output:
 ```go
 package main
 
-import fmt "fmt"
+import "fmt"
 
 func main() {
 	fmt.Println("Hello, world")
@@ -847,7 +847,7 @@ fmt.Printf("%#v", f)
 // Output:
 // package a
 //
-// import unsafe "unsafe"
+// import "unsafe"
 //
 // /*
 // #include <stdio.h>
@@ -919,7 +919,7 @@ if err != nil {
 ```
 
 ### Anon
-Anon adds an anonymous import:
+Anon adds an anonymous import.
 
 ```go
 f := NewFile("c")
@@ -934,6 +934,62 @@ fmt.Printf("%#v", f)
 // func init() {}
 ```
 
+### ImportName
+ImportName provides the package name for a path. If specified, the alias will be omitted from the
+import block. This is optional. If not specified, a sensible package name is used based on the path
+and this is added as an alias in the import block.
+
+```go
+f := NewFile("main")
+
+// package a should use name "a"
+f.ImportName("github.com/foo/a", "a")
+
+// package b is not used in the code so will not be included
+f.ImportName("github.com/foo/b", "b")
+
+f.Func().Id("main").Params().Block(
+	Qual("github.com/foo/a", "A").Call(),
+)
+fmt.Printf("%#v", f)
+
+// Output:
+// package main
+//
+// import "github.com/foo/a"
+//
+// func main() {
+// 	a.A()
+// }
+```
+
+### ImportAlias
+ImportAlias provides the alias for a package path that should be used in the import block.
+
+```go
+f := NewFile("main")
+
+// package a should be aliased to "b"
+f.ImportAlias("github.com/foo/a", "b")
+
+// package c is not used in the code so will not be included
+f.ImportAlias("github.com/foo/c", "c")
+
+f.Func().Id("main").Params().Block(
+	Qual("github.com/foo/a", "A").Call(),
+)
+fmt.Printf("%#v", f)
+
+// Output:
+// package main
+//
+// import b "github.com/foo/a"
+//
+// func main() {
+// 	b.A()
+// }
+```
+
 ### Comments
 PackageComment adds a comment to the top of the file, above the package
 keyword.
@@ -961,22 +1017,22 @@ CgoPreamble adds a cgo preamble comment that is rendered directly before the "C"
 import.
 
 ### PackagePrefix
-If you're worried about package aliases conflicting with local variable
-names, you can set a prefix here. Package foo becomes {prefix}_foo.
+If you're worried about generated package aliases conflicting with local variable names, you
+can set a prefix here. Package foo becomes {prefix}_foo.
 
 ```go
-f := NewFile("c")
+f := NewFile("a")
 f.PackagePrefix = "pkg"
 f.Func().Id("main").Params().Block(
-	Qual("fmt", "Println").Call(),
+	Qual("b.c/d", "E").Call(),
 )
 fmt.Printf("%#v", f)
 // Output:
-// package c
+// package a
 //
-// import pkg_fmt "fmt"
+// import pkg_d "b.c/d"
 //
 // func main() {
-// 	pkg_fmt.Println()
+// 	pkg_d.E()
 // }
 ```
diff --git a/README.md.tpl b/README.md.tpl
@@ -391,6 +391,16 @@ the import is separated, and preceded by the preamble.
 
 {{ "ExampleFile_Anon" | example }}
 
+### ImportName
+{{ "File.ImportName" | doc }}
+
+{{ "ExampleFile_ImportName" | example }}
+
+### ImportAlias
+{{ "File.ImportAlias" | doc }}
+
+{{ "ExampleFile_ImportAlias" | example }}
+
 ### Comments
 {{ "File.PackageComment" | doc }}
 

diff --git a/genjen/render.go b/genjen/render.go
@@ -1,9 +1,14 @@
 package main
 
 import (
+	"go/build"
 	"io"
+	"os/exec"
 	"strings"
 
+	"fmt"
+	"path/filepath"
+
 	. "github.com/dave/jennifer/jen"
 )
 
@@ -202,6 +207,23 @@ func render(w io.Writer) error {
 		)
 	}
 
+	packages, err := getStandardLibraryPackages()
+	if err != nil {
+		return err
+	}
+	/*
+		// PackageNameHints is a map containing hints for the names of all standard library packages
+		var PackageNameHints = map[string]string{
+			...
+		}
+	*/
+	file.Comment("PackageNameHints is a map containing hints for the names of all standard library packages")
+	file.Var().Id("PackageNameHints").Op("=").Map(String()).String().Values(DictFunc(func(d Dict) {
+		for path, name := range packages {
+			d[Lit(path)] = Lit(name)
+		}
+	}))
+
 	return file.Render(w)
 }
 
@@ -254,3 +276,26 @@ func addFunctionAndGroupMethod(
 		Return(Id("s")),
 	)
 }
+
+func getStandardLibraryPackages() (map[string]string, error) {
+	cmd := exec.Command("go", "list", "-f", "{{ .ImportPath }} {{ .Name }}", "./...")
+	cmd.Env = []string{
+		fmt.Sprintf("GOPATH=%s", build.Default.GOPATH),
+		fmt.Sprintf("GOROOT=%s", build.Default.GOROOT),
+	}
+	cmd.Dir = filepath.Join(build.Default.GOROOT, "src")
+	b, err := cmd.CombinedOutput()
+	if err != nil {
+		return nil, err
+	}
+	all := strings.Split(strings.TrimSpace(string(b)), "\n")
+
+	packages := map[string]string{}
+	for _, j := range all {
+		parts := strings.Split(j, " ")
+		path := parts[0]
+		name := parts[1]
+		packages[path] = name
+	}
+	return packages, nil
+}
diff --git a/jen/examples_test.go b/jen/examples_test.go
@@ -8,6 +8,54 @@ import (
 	. "github.com/dave/jennifer/jen"
 )
 
+func ExampleFile_ImportName() {
+	f := NewFile("main")
+
+	// package a should use name "a"
+	f.ImportName("github.com/foo/a", "a")
+
+	// package b is not used in the code so will not be included
+	f.ImportName("github.com/foo/b", "b")
+
+	f.Func().Id("main").Params().Block(
+		Qual("github.com/foo/a", "A").Call(),
+	)
+	fmt.Printf("%#v", f)
+
+	// Output:
+	// package main
+	//
+	// import "github.com/foo/a"
+	//
+	// func main() {
+	// 	a.A()
+	// }
+}
+
+func ExampleFile_ImportAlias() {
+	f := NewFile("main")
+
+	// package a should be aliased to "b"
+	f.ImportAlias("github.com/foo/a", "b")
+
+	// package c is not used in the code so will not be included
+	f.ImportAlias("github.com/foo/c", "c")
+
+	f.Func().Id("main").Params().Block(
+		Qual("github.com/foo/a", "A").Call(),
+	)
+	fmt.Printf("%#v", f)
+
+	// Output:
+	// package main
+	//
+	// import b "github.com/foo/a"
+	//
+	// func main() {
+	// 	b.A()
+	// }
+}
+
 func ExampleFile_CgoPreamble() {
 	f := NewFile("a")
 	f.CgoPreamble(`#include <stdio.h>
@@ -26,7 +74,7 @@ void myprint(char* s) {
 	// Output:
 	// package a
 	//
-	// import unsafe "unsafe"
+	// import "unsafe"
 	//
 	// /*
 	// #include <stdio.h>
@@ -82,7 +130,7 @@ func ExampleFile_CgoPreamble_no_preamble() {
 	//
 	// import (
 	// 	"C"
-	// 	fmt "fmt"
+	// 	"fmt"
 	// )
 	//
 	// func init() {
@@ -132,7 +180,7 @@ func ExampleFile_CgoPreamble_no_preamble_anon() {
 	//
 	// import (
 	// 	"C"
-	// 	fmt "fmt"
+	// 	"fmt"
 	// )
 	//
 	// func init() {
@@ -1298,7 +1346,7 @@ func ExampleId_remote() {
 	// Output:
 	// package main
 	//
-	// import fmt "fmt"
+	// import "fmt"
 	//
 	// func main() {
 	// 	fmt.Println("Hello, world")
@@ -1329,7 +1377,7 @@ func ExampleNewFile() {
 	// Output:
 	// package main
 	//
-	// import fmt "fmt"
+	// import "fmt"
 	//
 	// func main() {
 	// 	fmt.Println("Hello, world")
@@ -1379,18 +1427,18 @@ func ExampleFile_Anon() {
 }
 
 func ExampleFile_PackagePrefix() {
-	f := NewFile("c")
+	f := NewFile("a")
 	f.PackagePrefix = "pkg"
 	f.Func().Id("main").Params().Block(
-		Qual("fmt", "Println").Call(),
+		Qual("b.c/d", "E").Call(),
 	)
 	fmt.Printf("%#v", f)
 	// Output:
-	// package c
+	// package a
 	//
-	// import pkg_fmt "fmt"
+	// import pkg_d "b.c/d"
 	//
 	// func main() {
-	// 	pkg_fmt.Println()
+	// 	pkg_d.E()
 	// }
 }