Add move constructor to C++ USDT instance (iovisor#1962)

* Small fix on C++ USDT implementation

Fix an logging error, and small optimization on initialization

* Add move constructor to C++ USDT instance

src/cc/api/BPF.cc

@@ -59,10 +59,13 @@ StatusTuple BPF::init(const std::string& bpf_program,
  const std::vector<USDT>& usdt) {
  std::string all_bpf_program;
 
+ usdt_.reserve(usdt.size());
  for (const auto& u : usdt) {
  usdt_.emplace_back(u);
- TRY2(usdt_.back().init());
- all_bpf_program += usdt_.back().program_text_;
+ }
+ for (auto& u : usdt_) {
+ TRY2(u.init());
+ all_bpf_program += u.program_text_;
  }
 
  auto flags_len = cflags.size();
@@ -733,6 +736,18 @@ USDT::USDT(const USDT& usdt)
  name_(usdt.name_),
  probe_func_(usdt.probe_func_) {}
 
+USDT::USDT(USDT&& usdt) noexcept
+ : initialized_(usdt.initialized_),
+ binary_path_(std::move(usdt.binary_path_)),
+ pid_(usdt.pid_),
+ provider_(std::move(usdt.provider_)),
+ name_(std::move(usdt.name_)),
+ probe_func_(std::move(usdt.probe_func_)),
+ probe_(std::move(usdt.probe_)),
+ program_text_(std::move(usdt.program_text_)) {
+ usdt.initialized_ = false;
+}
+
 bool USDT::operator==(const USDT& other) const {
  return (provider_ == other.provider_) && (name_ == other.name_) &&
  (binary_path_ == other.binary_path_) && (pid_ == other.pid_) &&

src/cc/api/BPF.h

@@ -245,14 +245,15 @@ class USDT {
  USDT(const std::string& binary_path, pid_t pid, const std::string& provider,
  const std::string& name, const std::string& probe_func);
  USDT(const USDT& usdt);
+ USDT(USDT&& usdt) noexcept;
 
  StatusTuple init();
 
  bool operator==(const USDT& other) const;
 
  std::string print_name() const {
  return provider_ + ":" + name_ + " from binary " + binary_path_ + " PID " +
- std::to_string(pid_) + " for probe " + "probe_func_";
+ std::to_string(pid_) + " for probe " + probe_func_;
  }
 
  friend std::ostream& operator<<(std::ostream& out, const USDT& usdt) {