[Lldb-commits] [lldb] [debugserver] Implement MultiMemRead packet (PR #162670)

[Jason Molenda via lldb-commits]

================
@@ -3160,6 +3165,140 @@ rnb_err_t RNBRemote::HandlePacket_m(const char *p) {
   return SendPacket(ostrm.str());
 }
 
+/// Returns true if `str` starts with `prefix`.
+static bool starts_with(std::string_view str, std::string_view prefix) {
+  return str.size() >= prefix.size() &&
+         str.compare(0, prefix.size(), prefix) == 0;
+}
+
+/// Attempts to parse a prefix of `number_str` as a number of type `T`. If
+/// successful, the number is returned and the prefix is dropped from
+/// `number_str`.
+template <typename T>
+static std::optional<T> extract_number(std::string_view &number_str) {
+  static_assert(std::is_integral<T>());
+  char *str_end = nullptr;
+  errno = 0;
+  nub_addr_t number = strtoull(number_str.data(), &str_end, 16);
+  if (errno != 0)
+    return std::nullopt;
+  assert(str_end);
+  number_str.remove_prefix(str_end - number_str.data());
+  return number;
+}
+
+/// Splits `list_str` into multiple string_views separated by `,`.
+static std::vector<std::string_view>
+parse_comma_separated_list(std::string_view list_str) {
+  std::vector<std::string_view> list;
+  while (!list_str.empty()) {
+    auto pos = list_str.find(',');
+    list.push_back(list_str.substr(0, pos));
+    if (pos == list_str.npos)
+      break;
+    list_str.remove_prefix(pos + 1);
+  }
+  return list;
+}
+
+rnb_err_t RNBRemote::HandlePacket_MultiMemRead(const char *p) {
+  const std::string_view packet_name("MultiMemRead:");
+  std::string_view packet(p);
+
+  if (!starts_with(packet, packet_name))
+    return HandlePacket_ILLFORMED(__FILE__, __LINE__, p,
+                                  "Invalid MultiMemRead packet prefix");
+
+  packet.remove_prefix(packet_name.size());
+
+  const std::string_view ranges_prefix("ranges:");
+  if (!starts_with(packet, ranges_prefix))
----------------
jasonmolenda wrote:

If we're doing key-value pairs, I wouldn't hardcode that this key name must be first in the packet.  It's an extra thing to handle in the future when we have additional keys "old debugservers need this key to come first".

https://github.com/llvm/llvm-project/pull/162670