redesign cli

This is a major rebuilding of the CLI. The library part is split out
into pkilib and the cli handles only the communication with the user,
I/O and the library.
The API will still look the same, but the code should be much better to
grasp. Instead of repeating everything, more will be grouped together
and reused.

1 files changed, 41 insertions, 0 deletions

diff --git a/io.go b/io.go
new file mode 100644
index 0000000..382044e
--- /dev/null
+++ b/io.go
@@ -0,0 +1,41 @@
+package main
+
+// handle all io and de/encoding of data
+
+import (
+  "encoding/pem"
+  "errors"
+  "io/ioutil"
+)
+
+var (
+  ErrBlockNotFound = errors.New("block not found")
+)
+
+// load a pem section from a file
+func readSectionFromFile(path, btype string) ([]byte, error) {
+  raw, err := readFile(path)
+  if err != nil { return raw, err }
+
+  return decodeSection(raw, btype)
+}
+
+// read a file completely and report possible errors
+func readFile(path string) ([]byte, error) {
+  raw, err := ioutil.ReadFile(path)
+  if err != nil { return EmptyByteArray, err }
+  return raw, nil
+}
+
+// decode a pem encoded file and search for the specified section
+func decodeSection(data []byte, btype string) ([]byte, error) {
+  rest := data
+  for len(rest) > 0 {
+    var block *pem.Block
+    block, rest = pem.Decode(rest)
+    if block.Type == btype {
+      return block.Bytes, nil
+    }
+  }
+  return EmptyByteArray, ErrBlockNotFound
+}