pldm: use std::expected for instance ID allocation

Refactor InstanceIdDb::next() to return
std::expected<uint8_t, InstanceIdError> instead of throwing exceptions.
This change enables callers to explicitly handle allocation errors via
value inspection, rather than relying on exception handling.

This approach prevents core dumps from uncaught exceptions and
eliminates the need for pervasive try-catch blocks.
Callers can now access the error code and message directly, improving
clarity and control of error propagation.

Note:
Errors from InstanceIdDb::next() are currently handled via early
return, which may silently discard failures.
This is a temporary solution; APIs and callers will need to be updated
in the future to propagate and handle errors explicitly.

Change-Id: Ibf2e0034b0ee725cb59adfd93b74e48db8c42cba
Signed-off-by: Eric Yang <eric.yang.wiwynn@gmail.com>
diff --git a/platform-mc/dbus_to_terminus_effecters.cpp b/platform-mc/dbus_to_terminus_effecters.cpp
index 0c27f95..594e3c4 100644
--- a/platform-mc/dbus_to_terminus_effecters.cpp
+++ b/platform-mc/dbus_to_terminus_effecters.cpp
@@ -481,7 +481,13 @@
         }
     }
 
-    auto instanceId = instanceIdDb->next(mctpEid);
+    auto instanceIdResult =
+        pldm::utils::getInstanceId(instanceIdDb->next(mctpEid));
+    if (!instanceIdResult)
+    {
+        return PLDM_ERROR;
+    }
+    auto instanceId = instanceIdResult.value();
     int rc = PLDM_ERROR;
     std::vector<uint8_t> requestMsg;
 
@@ -620,7 +626,13 @@
     }
 
     uint8_t& compEffCnt = hostEffecterInfo[effecterInfoIndex].compEffecterCnt;
-    auto instanceId = instanceIdDb->next(mctpEid);
+    auto instanceIdResult =
+        pldm::utils::getInstanceId(instanceIdDb->next(mctpEid));
+    if (!instanceIdResult)
+    {
+        return PLDM_ERROR;
+    }
+    auto instanceId = instanceIdResult.value();
 
     std::vector<uint8_t> requestMsg(
         sizeof(pldm_msg_hdr) + sizeof(effecterId) + sizeof(compEffCnt) +
diff --git a/platform-mc/terminus_manager.cpp b/platform-mc/terminus_manager.cpp
index d90b6cf..bd77fe6 100644
--- a/platform-mc/terminus_manager.cpp
+++ b/platform-mc/terminus_manager.cpp
@@ -464,7 +464,12 @@
 
 exec::task<int> TerminusManager::getTidOverMctp(mctp_eid_t eid, pldm_tid_t* tid)
 {
-    auto instanceId = instanceIdDb.next(eid);
+    auto instanceIdResult = pldm::utils::getInstanceId(instanceIdDb.next(eid));
+    if (!instanceIdResult)
+    {
+        co_return PLDM_ERROR;
+    }
+    auto instanceId = instanceIdResult.value();
     Request request(sizeof(pldm_msg_hdr));
     auto requestMsg = new (request.data()) pldm_msg;
     auto rc = encode_get_tid_req(instanceId, requestMsg);
@@ -510,7 +515,12 @@
 
 exec::task<int> TerminusManager::setTidOverMctp(mctp_eid_t eid, pldm_tid_t tid)
 {
-    auto instanceId = instanceIdDb.next(eid);
+    auto instanceIdResult = pldm::utils::getInstanceId(instanceIdDb.next(eid));
+    if (!instanceIdResult)
+    {
+        co_return PLDM_ERROR;
+    }
+    auto instanceId = instanceIdResult.value();
     Request request(sizeof(pldm_msg_hdr) + sizeof(pldm_set_tid_req));
     auto requestMsg = new (request.data()) pldm_msg;
     auto rc = encode_set_tid_req(instanceId, tid, requestMsg);
@@ -684,7 +694,12 @@
 
     auto eid = std::get<0>(mctpInfo.value());
     auto requestMsg = new (request.data()) pldm_msg;
-    requestMsg->hdr.instance_id = instanceIdDb.next(eid);
+    auto instanceIdResult = pldm::utils::getInstanceId(instanceIdDb.next(eid));
+    if (!instanceIdResult)
+    {
+        co_return PLDM_ERROR;
+    }
+    requestMsg->hdr.instance_id = instanceIdResult.value();
     auto rc = co_await sendRecvPldmMsgOverMctp(eid, request, responseMsg,
                                                responseLen);