plugin: new package for loading plugins
Includes a linux implementation.
Change-Id: Iacc2ed7da760ae9deebc928adf2b334b043b07ec
Reviewed-on: https://go-review.googlesource.com/27823
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/src/plugin/plugin.go b/src/plugin/plugin.go
new file mode 100644
index 0000000..66cf2f9
--- /dev/null
+++ b/src/plugin/plugin.go
@@ -0,0 +1,70 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package plugin implements loading and symbol resolution of Go plugins.
+//
+// Currently plugins only work on Linux.
+//
+// A plugin is a Go main package with exported functions and variables that
+// has been built with:
+//
+// go build -buildmode=plugin
+//
+// When a plugin is first opened, the init functions of all packages not
+// already part of the program are called. The main function is not run.
+// A plugin is only initialized once, and cannot be closed.
+package plugin
+
+// Plugin is a loaded Go plugin.
+type Plugin struct {
+ name string
+ loaded chan struct{} // closed when loaded
+ syms map[string]interface{}
+}
+
+// Open opens a Go plugin.
+func Open(path string) (*Plugin, error) {
+ return open(path)
+}
+
+// Lookup searches for a symbol named symName in plugin p.
+// A symbol is any exported variable or function.
+// It reports an error if the symbol is not found.
+func (p *Plugin) Lookup(symName string) (Symbol, error) {
+ return lookup(p, symName)
+}
+
+// A Symbol is a pointer to a variable or function.
+//
+// For example, a plugin defined as
+//
+// package main
+//
+// // // No C code needed.
+// import "C"
+//
+// import "fmt"
+//
+// var V int
+//
+// func F() { fmt.Println("Hello, number %d", V) }
+//
+// may be loaded with the Open function and then the exported package
+// symbols V and F can be accessed
+//
+// p, err := plugin.Open("plugin_name.so")
+// if err != nil {
+// panic(err)
+// }
+// v, err := p.Lookup("V")
+// if err != nil {
+// panic(err)
+// }
+// f, err := p.Lookup("F")
+// if err != nil {
+// panic(err)
+// }
+// *v.(*int) = 7
+// f.(func())() // prints "Hello, number 7"
+type Symbol interface{}
