Move sources into firebase::firestore and internal namespaces (#494)

* Move sources into firebase::firestore and internal namespaces

Combine support and core/util packages; this distinction wasn't really
paying its freight.

5 files changed, 204 insertions, 0 deletions

diff --git a/Firestore/core/src/firebase/firestore/util/CMakeLists.txt b/Firestore/core/src/firebase/firestore/util/CMakeLists.txt
new file mode 100644
index 0000000..ce81363
--- /dev/null
+++ b/Firestore/core/src/firebase/firestore/util/CMakeLists.txt
@@ -0,0 +1,19 @@
+# Copyright 2017 Google
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+add_library(
+  firebase_firestore_util
+  autoid.cc
+  secure_random_arc4random.cc
+)
diff --git a/Firestore/core/src/firebase/firestore/util/autoid.cc b/Firestore/core/src/firebase/firestore/util/autoid.cc
new file mode 100644
index 0000000..10a2cde
--- /dev/null
+++ b/Firestore/core/src/firebase/firestore/util/autoid.cc
@@ -0,0 +1,56 @@
+/*
+ * Copyright 2017 Google
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "Firestore/core/src/firebase/firestore/util/autoid.h"
+
+#include <random>
+#include <string>
+
+#include "Firestore/core/src/firebase/firestore/util/secure_random.h"
+
+namespace firebase {
+namespace firestore {
+namespace util {
+
+namespace {
+
+const int kAutoIdLength = 20;
+const char kAutoIdAlphabet[] =
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
+
+SecureRandom shared_random;
+
+}  // namespace
+
+std::string CreateAutoId() {
+  std::string auto_id;
+  auto_id.reserve(kAutoIdLength);
+
+  // -2 here because:
+  //   * sizeof(kAutoIdAlphabet) includes the trailing null terminator
+  //   * uniform_int_distribution is inclusive on both sizes
+  std::uniform_int_distribution<int> letters(0, sizeof(kAutoIdAlphabet) - 2);
+
+  for (int i = 0; i < kAutoIdLength; i++) {
+    int rand_index = letters(shared_random);
+    auto_id.append(1, kAutoIdAlphabet[rand_index]);
+  }
+  return auto_id;
+}
+
+}  // namespace util
+}  // namespace firestore
+}  // namespace firebase
diff --git a/Firestore/core/src/firebase/firestore/util/autoid.h b/Firestore/core/src/firebase/firestore/util/autoid.h
new file mode 100644
index 0000000..22d7d7d
--- /dev/null
+++ b/Firestore/core/src/firebase/firestore/util/autoid.h
@@ -0,0 +1,33 @@
+/*
+ * Copyright 2017 Google
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_UTIL_AUTOID_H_
+#define FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_UTIL_AUTOID_H_
+
+#include <string>
+
+namespace firebase {
+namespace firestore {
+namespace util {
+
+// Generates a random ID suitable for use as a document ID.
+std::string CreateAutoId();
+
+}  // namespace util
+}  // namespace firestore
+}  // namespace firebase
+
+#endif  // FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_UTIL_AUTOID_H_
diff --git a/Firestore/core/src/firebase/firestore/util/secure_random.h b/Firestore/core/src/firebase/firestore/util/secure_random.h
new file mode 100644
index 0000000..72be1bd
--- /dev/null
+++ b/Firestore/core/src/firebase/firestore/util/secure_random.h
@@ -0,0 +1,59 @@
+/*
+ * Copyright 2017 Google
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_UTIL_SECURE_RANDOM_H_
+#define FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_UTIL_SECURE_RANDOM_H_
+
+#include <stdint.h>
+
+#include <limits>
+
+namespace firebase {
+namespace firestore {
+namespace util {
+
+// A "secure" pseudorandom number generator, suitable for generating
+// unguessable identifiers. This exists because
+//
+//   * std::mt19937 is blazing fast but its outputs can be guessed once enough
+//     previous outputs have been observed.
+//   * std::random_device isn't guaranteed to come from a secure PRNG or be
+//     fast.
+//
+// The implementation satisfies the C++11 UniformRandomBitGenerator concept and
+// delegates to an implementation that generates high quality random values
+// quickly with periodic reseeding.
+class SecureRandom {
+ public:
+  // C++11 UniformRandomBitGenerator interface
+  using result_type = uint32_t;
+
+  static constexpr result_type min() {
+    return std::numeric_limits<result_type>::min();
+  }
+
+  static constexpr result_type max() {
+    return std::numeric_limits<result_type>::max();
+  }
+
+  result_type operator()();
+};
+
+}  // namespace util
+}  // namespace firestore
+}  // namespace firebase
+
+#endif  // FIRESTORE_CORE_SRC_FIREBASE_FIRESTORE_UTIL_SECURE_RANDOM_H_
diff --git a/Firestore/core/src/firebase/firestore/util/secure_random_arc4random.cc b/Firestore/core/src/firebase/firestore/util/secure_random_arc4random.cc
new file mode 100644
index 0000000..a76ade3
--- /dev/null
+++ b/Firestore/core/src/firebase/firestore/util/secure_random_arc4random.cc
@@ -0,0 +1,37 @@
+/*
+ * Copyright 2017 Google
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "Firestore/core/src/firebase/firestore/util/secure_random.h"
+
+#include "Firestore/core/src/firebase/firestore/base/port.h"
+
+#if HAVE_ARC4RANDOM
+
+#include <stdlib.h>
+
+namespace firebase {
+namespace firestore {
+namespace util {
+
+SecureRandom::result_type SecureRandom::operator()() {
+  return arc4random();
+}
+
+}  // namespace util
+}  // namespace firestore
+}  // namespace firebase
+
+#endif  // HAVE_ARC4RANDOM