Merge bitcoin/bitcoin#26261: p2p: cleanup `LookupIntern`, `Lookup` and `LookupHost`

5c832c3820253affc65c0ed490e26e5b0a4d5c9b p2p, refactor: return `std::optional<CNetAddr>` in `LookupHost` (brunoerg)
34bcdfc6a65de906c65edccdd96fe15219081cd2 p2p, refactor: return vector/optional<CService> in `Lookup` (brunoerg)
7799eb125b7a1146f8251be5d26df574236212a9 p2p, refactor: return `std::vector<CNetAddr>` in `LookupHost` (brunoerg)
5c1774a563dcc237a88df69569cd94fe81e908f7 p2p, refactor: return `std::vector<CNetAddr>` in `LookupIntern` (brunoerg)

Pull request description:

  Continuation of #26078.

  To improve readability instead of returning a bool and passing stuff by reference, this PR changes:

  - `LookupHost` to return `std::vector<CNetAddr>`
  - `LookupHost` to return `std::optional<CNetAddr>`
  - `Lookup` to return `std::vector<CService>`
  - `Lookup` to return `std::optional<CService>`.
  - `LookupIntern` to return `std::vector<CNetAddr>`

  As discussed in #26078, it would be better to avoid using `optional` in some cases, but for specific `Lookup` and `LookupHost` functions it's necessary to use `optional` to verify if they were able to catch some data from their overloaded function.

ACKs for top commit:
  achow101:
    ACK 5c832c3820253affc65c0ed490e26e5b0a4d5c9b
  stickies-v:
    re-ACK 5c832c3820253affc65c0ed490e26e5b0a4d5c9b - just addressing two nits, no other changes
  theStack:
    re-ACK 5c832c3820253affc65c0ed490e26e5b0a4d5c9b

Tree-SHA512: ea346fdc54463999646269bd600cd4a1590ef958001d2f0fc2be608ca51e1b4365efccca76dd4972b023e12fcc6e67d226608b0df7beb901bdeadd19948df840

1 files changed, 4 insertions, 4 deletions

diff --git a/src/net_permissions.cpp b/src/net_permissions.cpp
index 1e4ec5b529..23226bbb4f 100644
--- a/src/net_permissions.cpp
+++ b/src/net_permissions.cpp
@@ -88,18 +88,18 @@ bool NetWhitebindPermissions::TryParse(const std::string& str, NetWhitebindPermi
     if (!TryParsePermissionFlags(str, flags, offset, error)) return false;
 
     const std::string strBind = str.substr(offset);
-    CService addrBind;
-    if (!Lookup(strBind, addrBind, 0, false)) {
+    const std::optional<CService> addrBind{Lookup(strBind, 0, false)};
+    if (!addrBind.has_value()) {
         error = ResolveErrMsg("whitebind", strBind);
         return false;
     }
-    if (addrBind.GetPort() == 0) {
+    if (addrBind.value().GetPort() == 0) {
         error = strprintf(_("Need to specify a port with -whitebind: '%s'"), strBind);
         return false;
     }
 
     output.m_flags = flags;
-    output.m_service = addrBind;
+    output.m_service = addrBind.value();
     error = Untranslated("");
     return true;
 }