Small Uuid class wrapping libuuid.

This will be used to generate the names of sample files,
as well as camera ids.

src/CMakeLists.txt

@@ -39,7 +39,8 @@ set(MOONFIRE_DEPS
     ${PROFILER_LIBRARIES}
     ${PROTOBUF_LIBRARIES}
     ${RE2_LIBRARIES}
-    ${SQLITE_LIBRARIES})
+    ${SQLITE_LIBRARIES}
+    ${UUID_LIBRARIES})
 
 set(MOONFIRE_NVR_SRCS
     coding.cc
@@ -54,7 +55,8 @@ set(MOONFIRE_NVR_SRCS
     recording.cc
     sqlite.cc
     string.cc
-    time.cc)
+    time.cc
+    uuid.cc)
 
 add_library(moonfire-nvr-lib ${MOONFIRE_NVR_SRCS} ${PROTO_SRCS} ${PROTO_HDRS})
 target_link_libraries(moonfire-nvr-lib ${MOONFIRE_DEPS})

src/uuid.cc

@@ -0,0 +1,94 @@
+// This file is part of Moonfire NVR, a security camera network video recorder.
+// Copyright (C) 2016 Lamb <slamb@slamb.org>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// In addition, as a special exception, the copyright holders give
+// permission to link the code of portions of this program with the
+// OpenSSL library under certain conditions as described in each
+// individual source file, and distribute linked combinations including
+// the two.
+//
+// You must obey the GNU General Public License in all respects for all
+// of the code used other than OpenSSL. If you modify file(s) with this
+// exception, you may extend this exception to your version of the
+// file(s), but you are not obligated to do so. If you do not wish to do
+// so, delete this exception statement from your version. If you delete
+// this exception statement from all source files in the program, then
+// also delete it here.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+// uuid.cc: implementation of uuid.h interface.
+
+#include "uuid.h"
+
+namespace moonfire_nvr {
+
+namespace {
+
+const size_t kTextFormatLength =
+    sizeof("xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx") - 1;
+
+}  // namespace
+
+bool Uuid::ParseText(re2::StringPiece input) {
+  if (input.size() != kTextFormatLength) {
+    return false;
+  }
+  char tmp[kTextFormatLength + 1];
+  memcpy(tmp, input.data(), kTextFormatLength);
+  tmp[kTextFormatLength] = 0;
+  return uuid_parse(tmp, me_) == 0;
+}
+
+bool Uuid::ParseBinary(re2::StringPiece input) {
+  if (input.size() != sizeof(uuid_t)) {
+    return false;
+  }
+  memcpy(me_, input.data(), sizeof(uuid_t));
+  return true;
+}
+
+std::string Uuid::UnparseText() const {
+  char tmp[kTextFormatLength + 1];
+  uuid_unparse_lower(me_, tmp);
+  return tmp;
+}
+
+re2::StringPiece Uuid::binary_view() const {
+  return re2::StringPiece(reinterpret_cast<const char *>(me_), sizeof(me_));
+}
+
+bool Uuid::operator==(const Uuid &other) const {
+  return uuid_compare(me_, other.me_) == 0;
+}
+
+bool Uuid::operator<(const Uuid &other) const {
+  return uuid_compare(me_, other.me_) < 0;
+}
+
+class RealUuidGenerator : public UuidGenerator {
+ public:
+  Uuid Generate() final {
+    Uuid out;
+    uuid_generate(out.me_);
+    return out;
+  }
+};
+
+UuidGenerator *GetRealUuidGenerator() {
+  static RealUuidGenerator *gen = new RealUuidGenerator;  // never freed.
+  return gen;
+}
+
+}  // namespace moonfire_nvr

src/uuid.h

@@ -0,0 +1,79 @@
+// This file is part of Moonfire NVR, a security camera network video recorder.
+// Copyright (C) 2016 Lamb <slamb@slamb.org>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// In addition, as a special exception, the copyright holders give
+// permission to link the code of portions of this program with the
+// OpenSSL library under certain conditions as described in each
+// individual source file, and distribute linked combinations including
+// the two.
+//
+// You must obey the GNU General Public License in all respects for all
+// of the code used other than OpenSSL. If you modify file(s) with this
+// exception, you may extend this exception to your version of the
+// file(s), but you are not obligated to do so. If you do not wish to do
+// so, delete this exception statement from your version. If you delete
+// this exception statement from all source files in the program, then
+// also delete it here.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+// uuid.h: small wrapper around the C UUID library for generating/parsing
+// RFC 4122 UUIDs.
+
+#ifndef MOONFIRE_NVR_UUID_H
+#define MOONFIRE_NVR_UUID_H
+
+#include <re2/stringpiece.h>
+#include <uuid/uuid.h>
+
+namespace moonfire_nvr {
+
+class Uuid {
+ public:
+  // Create a null uuid.
+  Uuid() { uuid_clear(me_); }
+
+  // Parse the text UUID. Returns success.
+  bool ParseText(re2::StringPiece input);
+
+  // Parse a binary UUID. In practice any 16-byte string is considered valid.
+  bool ParseBinary(re2::StringPiece input);
+
+  // Return a 36-byte lowercase text representation, such as
+  // 1b4e28ba-2fa1-11d2-883f-0016d3cca427.
+  std::string UnparseText() const;
+
+  // Return a reference to the 16-byte binary form.
+  // Invalidated by any change to the Uuid object.
+  re2::StringPiece binary_view() const;
+
+  bool operator==(const Uuid &) const;
+  bool operator<(const Uuid &) const;
+
+ private:
+  friend class RealUuidGenerator;
+  uuid_t me_;
+};
+
+class UuidGenerator {
+ public:
+  virtual ~UuidGenerator() {}
+  virtual Uuid Generate() = 0;
+};
+
+UuidGenerator *GetRealUuidGenerator();
+
+}  // namespace moonfire_nvr
+
+#endif  // MOONFIRE_NVR_CODING_H