[Sync] Persist keystore key across restarts

sync/util/cryptographer.cc

Index: sync/util/cryptographer.cc
diff --git a/sync/util/cryptographer.cc b/sync/util/cryptographer.cc
index f6b0e65565ab82a1883237520cb0ddea53c1ea23..350a237d898695f3c7cf99f829be38d1cf8fa96b 100644
--- a/sync/util/cryptographer.cc
+++ b/sync/util/cryptographer.cc
@@ -52,6 +52,25 @@ void Cryptographer::Bootstrap(const std::string& restored_bootstrap_token) {
     AddKeyImpl(nigori.release());
 }
 
+ void Cryptographer::BootstrapKeystoreKey(
+    const std::string& restored_bootstrap_token) {
+  if (keystore_nigori_) {
+    NOTREACHED();
+    return;
+  }
+
+  scoped_ptr<Nigori> nigori(UnpackBootstrapToken(restored_bootstrap_token));
+  if (!nigori.get())
+    return;
+  // AddKeyImpl updates the default nigori, so we save the current default and
+  // make sure the keystore_nigori_ gets updated instead.
+  NigoriMap::value_type* old_default = default_nigori_;

[rlarocque, 2012/06/13 23:35:04]

Why use linked_ptr<>*?

[Nicolas Zea, 2012/06/15 00:42:07]

Because they're also contained within the nigori keybag (an array of
linked_ptr<Nigori>'s), and I'm making a copy of it.

That said, I didn't like this hacky swap, so I've gone ahead and added an extra
param to AddKeyImpl so I could use it properly, removing the need for this
logic.

+  if (AddKeyImpl(nigori.release())) {
+    keystore_nigori_ = default_nigori_;
+    default_nigori_ = old_default;
+  }
+}
+
 bool Cryptographer::CanDecrypt(const sync_pb::EncryptedData& data) const {
   return nigoris_.end() != nigoris_.find(data.key_name());
 }
@@ -222,6 +241,15 @@ bool Cryptographer::GetBootstrapToken(std::string* token) const {
   return PackBootstrapToken(default_nigori_->second.get(), token);
 }
 
+bool Cryptographer::GetKeystoreKeyBootstrapToken(
+    std::string* token) const {
+  DCHECK(token);
+  if (!HasKeystoreKey())
+    return false;
+
+  return PackBootstrapToken(keystore_nigori_->second.get(), token);
+}
+
 bool Cryptographer::PackBootstrapToken(const Nigori* nigori,
                                        std::string* pack_into) const {
   DCHECK(pack_into);
@@ -325,7 +353,7 @@ bool Cryptographer::SetKeystoreKey(const std::string& keystore_key) {
   return false;
 }
 
-bool Cryptographer::HasKeystoreKey() {
+bool Cryptographer::HasKeystoreKey() const {
   return keystore_nigori_ != NULL;
 }