Add :save and :pipe commands to viewer

* :save takes a path and saves the current message part to that location
* :pipe is the same as pipe on the account page, but uses the current
  message part rather than the whole email (ie :pipe gzip -d)
* Refactored account:pipe and extracted common pipe code to
  commands.util.QuickTerm
* Added helper command aerc.PushError

commands/account/pipe.go

@@ -3,12 +3,9 @@ package account
 import (
 	"errors"
 	"io"
-	"os/exec"
-	"time"
 
+	"git.sr.ht/~sircmpwn/aerc/commands"
 	"git.sr.ht/~sircmpwn/aerc/widgets"
-
-	"github.com/gdamore/tcell"
 )
 
 func init() {
@@ -23,44 +20,13 @@ func Pipe(aerc *widgets.Aerc, args []string) error {
 	store := acct.Messages().Store()
 	msg := acct.Messages().Selected()
 	store.FetchFull([]uint32{msg.Uid}, func(reader io.Reader) {
-		cmd := exec.Command(args[1], args[2:]...)
-		pipe, err := cmd.StdinPipe()
+		term, err := commands.QuickTerm(aerc, args[1:], reader)
 		if err != nil {
-			aerc.PushStatus(" "+err.Error(), 10*time.Second).
-				Color(tcell.ColorDefault, tcell.ColorRed)
-			return
-		}
-		term, err := widgets.NewTerminal(cmd)
-		if err != nil {
-			aerc.PushStatus(" "+err.Error(), 10*time.Second).
-				Color(tcell.ColorDefault, tcell.ColorRed)
+			aerc.PushError(" " + err.Error())
 			return
 		}
 		name := args[1] + " <" + msg.Envelope.Subject
 		aerc.NewTab(term, name)
-		term.OnClose = func(err error) {
-			if err != nil {
-				aerc.PushStatus(" "+err.Error(), 10*time.Second).
-					Color(tcell.ColorDefault, tcell.ColorRed)
-			} else {
-				aerc.PushStatus("Process complete, press any key to close.",
-					10*time.Second)
-				term.OnEvent = func(event tcell.Event) bool {
-					aerc.RemoveTab(term)
-					return true
-				}
-			}
-		}
-		term.OnStart = func() {
-			go func() {
-				_, err := io.Copy(pipe, reader)
-				if err != nil {
-					aerc.PushStatus(" "+err.Error(), 10*time.Second).
-						Color(tcell.ColorDefault, tcell.ColorRed)
-				}
-				pipe.Close()
-			}()
-		}
 	})
 	return nil
 }

commands/msgview/pipe.go

@@ -0,0 +1,45 @@
+package msgview
+
+import (
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"io"
+	"mime/quotedprintable"
+
+	"git.sr.ht/~sircmpwn/aerc/commands"
+	"git.sr.ht/~sircmpwn/aerc/widgets"
+)
+
+func init() {
+	register("pipe", Pipe)
+}
+
+func Pipe(aerc *widgets.Aerc, args []string) error {
+	if len(args) < 2 {
+		return errors.New("Usage: :pipe <cmd> [args...]")
+	}
+
+	mv := aerc.SelectedTab().(*widgets.MessageViewer)
+	p := mv.CurrentPart()
+
+	p.Store.FetchBodyPart(p.Msg.Uid, p.Index, func(reader io.Reader) {
+		// email parts are encoded as 7bit (plaintext), quoted-printable, or base64
+		switch p.Part.Encoding {
+		case "base64":
+			reader = base64.NewDecoder(base64.StdEncoding, reader)
+		case "quoted-printable":
+			reader = quotedprintable.NewReader(reader)
+		}
+
+		term, err := commands.QuickTerm(aerc, args[1:], reader)
+		if err != nil {
+			aerc.PushError(" " + err.Error())
+			return
+		}
+		name := fmt.Sprintf("%s <%s/[%d]", args[1], p.Msg.Envelope.Subject, p.Index)
+		aerc.NewTab(term, name)
+	})
+
+	return nil
+}

commands/msgview/save.go

@@ -0,0 +1,59 @@
+package msgview
+
+import (
+	"encoding/base64"
+	"errors"
+	"io"
+	"mime/quotedprintable"
+	"os"
+	"time"
+
+	"git.sr.ht/~sircmpwn/aerc/widgets"
+	"github.com/mitchellh/go-homedir"
+)
+
+func init() {
+	register("save", Save)
+}
+
+func Save(aerc *widgets.Aerc, args []string) error {
+	if len(args) < 2 {
+		return errors.New("Usage: :save <path>")
+	}
+
+	mv := aerc.SelectedTab().(*widgets.MessageViewer)
+	p := mv.CurrentPart()
+
+	p.Store.FetchBodyPart(p.Msg.Uid, p.Index, func(reader io.Reader) {
+		// email parts are encoded as 7bit (plaintext), quoted-printable, or base64
+		switch p.Part.Encoding {
+		case "base64":
+			reader = base64.NewDecoder(base64.StdEncoding, reader)
+		case "quoted-printable":
+			reader = quotedprintable.NewReader(reader)
+		}
+
+		target, err := homedir.Expand(args[1])
+		if err != nil {
+			aerc.PushError(" " + err.Error())
+			return
+		}
+
+		f, err := os.Create(target)
+		if err != nil {
+			aerc.PushError(" " + err.Error())
+			return
+		}
+		defer f.Close()
+
+		_, err = io.Copy(f, reader)
+		if err != nil {
+			aerc.PushError(" " + err.Error())
+			return
+		}
+
+		aerc.PushStatus("Saved to "+target, 10*time.Second)
+	})
+
+	return nil
+}

commands/util.go

@@ -0,0 +1,56 @@
+package commands
+
+import (
+	"io"
+	"os/exec"
+	"time"
+
+	"git.sr.ht/~sircmpwn/aerc/widgets"
+	"github.com/gdamore/tcell"
+)
+
+// QuickTerm is an ephemeral terminal for running a single command and quiting.
+func QuickTerm(aerc *widgets.Aerc, args []string, stdin io.Reader) (*widgets.Terminal, error) {
+	cmd := exec.Command(args[0], args[1:]...)
+	pipe, err := cmd.StdinPipe()
+	if err != nil {
+		return nil, err
+	}
+
+	term, err := widgets.NewTerminal(cmd)
+	if err != nil {
+		return nil, err
+	}
+
+	term.OnClose = func(err error) {
+		if err != nil {
+			aerc.PushError(" " + err.Error())
+			// remove the tab on error, otherwise it gets stuck
+			aerc.RemoveTab(term)
+		} else {
+			aerc.PushStatus("Process complete, press any key to close.",
+				10*time.Second)
+			term.OnEvent = func(event tcell.Event) bool {
+				aerc.RemoveTab(term)
+				return true
+			}
+		}
+	}
+
+	term.OnStart = func() {
+		status := make(chan error, 1)
+
+		go func() {
+			_, err := io.Copy(pipe, stdin)
+			defer pipe.Close()
+			status <- err
+		}()
+
+		err := <-status
+		if err != nil {
+			aerc.PushError(" " + err.Error())
+		}
+	}
+
+	return term, nil
+}