Add onBufferOpen plugin callback

Closes #948

cmd/micro/micro.go

@@ -7,7 +7,6 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
-	"strings"
 	"time"
 
 	"github.com/go-errors/errors"
@@ -434,17 +433,13 @@ func main() {
 
 	for _, t := range tabs {
 		for _, v := range t.views {
-			for pl := range loadedPlugins {
-				_, err := Call(pl+".onViewOpen", v)
-				if err != nil && !strings.HasPrefix(err.Error(), "function does not exist") {
-					TermMessage(err)
-					continue
-				}
-			}
+			GlobalPluginCall("onViewOpen", v)
+			GlobalPluginCall("onBufferOpen", v.Buf)
 		}
 	}
 
 	InitColorscheme()
+	messenger.style = defStyle
 
 	// Here is the event loop which runs in a separate thread
 	go func() {

cmd/micro/plugin.go

@@ -170,3 +170,15 @@ func LoadPlugins() {
 		loadedPlugins["init"] = "init"
 	}
 }
+
+// GlobalCall makes a call to a function in every plugin that is currently
+// loaded
+func GlobalPluginCall(function string, args ...interface{}) {
+	for pl := range loadedPlugins {
+		_, err := Call(pl+"."+function, args...)
+		if err != nil && !strings.HasPrefix(err.Error(), "function does not exist") {
+			TermMessage(err)
+			continue
+		}
+	}
+}

cmd/micro/view.go

@@ -277,6 +277,8 @@ func (v *View) OpenBuffer(buf *Buffer) {
 	// is opened
 	v.isOverwriteMode = false
 	v.lastClickTime = time.Time{}
+
+	GlobalPluginCall("onBufferOpen", v.Buf)
 }
 
 // Open opens the given file in the view

runtime/help/plugins.md

@@ -45,6 +45,8 @@ view is passed in. This is useful for setting local options based on the
 filetype, for example turning off `tabstospaces` only for Go files when they are
 opened.
 
+Similar to `onViewOpen(view)` there is also `onBufferOpen(buf)`.
+
 ---
 
 There are a number of functions and variables that are available to you in order