Generate Instance ID locally.

components/gcm_driver/instance_id/instance_id_impl.cc

Index: components/gcm_driver/instance_id/instance_id_impl.cc
diff --git a/components/gcm_driver/instance_id/instance_id_impl.cc b/components/gcm_driver/instance_id/instance_id_impl.cc
index 4d76ad2286cde3fddb590f048170526d1b93b50c..c0ad8927f08863e79795308c12aa60f89cda3798 100644
--- a/components/gcm_driver/instance_id/instance_id_impl.cc
+++ b/components/gcm_driver/instance_id/instance_id_impl.cc
@@ -4,7 +4,13 @@
 
 #include "components/gcm_driver/instance_id/instance_id_impl.h"
 
+#include <algorithm>
+#include "base/base64.h"
+#include "base/bind.h"
 #include "base/logging.h"
+#include "base/message_loop/message_loop.h"
+#include "base/sha1.h"
+#include "crypto/rsa_private_key.h"
 
 namespace instance_id {
 
@@ -21,13 +27,13 @@ InstanceIDImpl::~InstanceIDImpl() {
 }
 
 std::string InstanceIDImpl::GetID() {
-  NOTIMPLEMENTED();
-  return std::string();
+  EnsureIDGenerated();
+  return id_;
 }
 
 base::Time InstanceIDImpl::GetCreationTime() {
-  NOTIMPLEMENTED();
-  return base::Time();
+  EnsureIDGenerated();

[fgorski, 2015/04/30 22:13:12]

Are you sure we should create ID when code queries for creation time? It would
be ok to return null time, as the ID is not created and was never requested.

It also allows to query if ID was at all created.

[jianli, 2015/05/02 00:30:18]

Sounds reasonable. Changed.

+  return creation_time_;
 }
 
 void InstanceIDImpl::GetToken(
@@ -45,7 +51,62 @@ void InstanceIDImpl::DeleteToken(const std::string& audience,
 }
 
 void InstanceIDImpl::DeleteID(const DeleteIDCallback& callback) {
-  NOTIMPLEMENTED();
+  // TODO(jianli): Delete the key pair from the store.
+  key_pair_.reset();
+  id_.clear();
+  creation_time_ = base::Time();
+
+  base::MessageLoop::current()->PostTask(
+      FROM_HERE,
+      base::Bind(callback, this, InstanceID::SUCCESS));
+}
+
+void InstanceIDImpl::EnsureIDGenerated() {
+  if (!id_.empty())
+    return;
+
+  // Generate the public/private key pair based on random number generator if
+  // not yet.
+  if (!key_pair_) {
+    key_pair_.reset(crypto::RSAPrivateKey::Create(2048));

[fgorski, 2015/04/30 22:13:12]

const kKeyLength?

[jianli, 2015/05/02 00:30:18]

Not needed any more.

+    if (!key_pair_) {
+      DVLOG(1) << "Cannot generate key pair.";
+      return;
+    }
+
+    // Record the time.
+    creation_time_ = base::Time::Now();
+
+    // TODO(jianli): Store the key pair.
+  }
+
+  // Now produce the ID based on the public key of the key pair.
+
+  // 1) Computes the SHA1 of public key of the key pair.
+  std::vector<uint8> public_key;
+  if (!key_pair_->ExportPublicKey(&public_key)) {
+    DVLOG(1) << "Cannot export public key.";
+    return;
+  }
+
+  uint8 digest[base::kSHA1Length];
+  base::SHA1HashBytes(public_key.data(), public_key.size(), digest);
+
+  // 2) Transforms the first 4 bits of the SHA1 value to 0x9.
+  uint8 d0 = digest[0];
+  d0 = 0x90 + (0xF & d0);
+  digest[0] = d0 & 0xFF;
+
+  // 3) Truncates the transformed SHA1 value to 8 bytes and encode it in in
+  //    Android-compatible base64 scheme:

[fgorski, 2015/04/30 22:13:12]

move below as point 4

[jianli, 2015/05/02 00:30:17]

Not needed any more.

+  //    * URL safe: '/' replaced by '_' and '+' replaced by '-'.
+  //    * No padding: any trailing '=' will be removed.
+  base::Base64Encode(
+      base::StringPiece(reinterpret_cast<const char*>(digest), 8),
+      &id_);
+  std::replace(id_.begin(), id_.end(), '+', '-');
+  std::replace(id_.begin(), id_.end(), '/', '_');
+  id_.erase(std::remove(id_.begin(), id_.end(), '='), id_.end());
 }
 
 }  // namespace instance_id