Header import, and dumporiginal extensions.

Add ability to dump headers or mimetypes for original messages.
Add ability to dump all messages, instead of just hashes listed.
Add new command  cmd/headers to import all headers from messages in table
    original.  Utility can work incrementally or do fully table imports.
Moved 'fetch all original messages' code to db/util.go.  Added conditional
version given table name that will only return original messages that do not
    have matching hashes in the specified table.

cmd/headers/headers.go

@@ -0,0 +1,63 @@
+package main
+
+import (
+	"bytes"
+	"flag"
+	"io"
+	"net/mail"
+	"xinu.tv/email/db"
+
+	"github.com/golang/glog"
+)
+
+var (
+	all = flag.Bool("all", false,
+		"extract headers from all messages. Default is to only extract from unprocessed messages.")
+)
+
+func insertHeaders(c *db.Conn, hash string, r io.Reader) error {
+	msg, err := mail.ReadMessage(r)
+	if err != nil {
+		return err
+	}
+	glog.Infoln("Insert", hash)
+	return c.InsertHeaders(hash, msg.Header)
+}
+
+func insertAllHeaders(c *db.Conn, all bool) error {
+	oCh := make(chan db.Original)
+	errc := make(chan error)
+	donec := make(chan struct{})
+	defer close(donec)
+	if all {
+		go c.Originals(oCh, errc, donec)
+	} else {
+		go c.OriginalsNotInTable("header", oCh, errc, donec)
+	}
+	for {
+		select {
+		case o := <-oCh:
+			r := bytes.NewReader(o.Blob)
+			if err := insertHeaders(c, o.Hash, r); err != nil {
+				return err
+			}
+		case err := <-errc:
+			return err
+		}
+	}
+}
+
+func main() {
+	defer glog.Flush()
+	flag.Parse()
+
+	c, err := db.NewConn("")
+	if err != nil {
+		glog.Fatal(err)
+	}
+
+	if err := insertAllHeaders(c, *all); err != nil {
+		glog.Fatal(err)
+	}
+
+}