[clang-tidy] apply readability-make-member-function-const (#5675)

src/core/common/timer.cpp

@@ -44,7 +44,7 @@ namespace ot {
 const TimerScheduler::AlarmApi TimerMilliScheduler::sAlarmMilliApi = {&otPlatAlarmMilliStartAt, &otPlatAlarmMilliStop,
                                                                       &otPlatAlarmMilliGetNow};
 
-bool Timer::DoesFireBefore(const Timer &aSecondTimer, Time aNow)
+bool Timer::DoesFireBefore(const Timer &aSecondTimer, Time aNow) const
 {
     bool retval;
     bool isBeforeNow = (GetFireTime() < aNow);

src/core/common/timer.hpp

@@ -132,7 +132,7 @@ protected:
      * @retval FALSE If the fire time of this timer object is the same or after aTimer's fire time.
      *
      */
-    bool DoesFireBefore(const Timer &aSecondTimer, Time aNow);
+    bool DoesFireBefore(const Timer &aSecondTimer, Time aNow) const;
 
     void Fired(void) { mHandler(*this); }
 

src/core/meshcop/joiner_router.hpp

@@ -89,7 +89,7 @@ private:
 
     struct JoinerEntrustMetadata
     {
-        otError AppendTo(Message &aMessage) { return aMessage.Append(*this); }
+        otError AppendTo(Message &aMessage) const { return aMessage.Append(*this); }
         void    ReadFrom(const Message &aMessage);
 
         Ip6::MessageInfo mMessageInfo; // Message info of the message to send.

src/core/net/ip6_mpl.hpp

@@ -106,7 +106,7 @@ public:
      * @returns The MPL Seed Id Length value.
      *
      */
-    SeedIdLength GetSeedIdLength(void) { return static_cast<SeedIdLength>(mControl & kSeedIdLengthMask); }
+    SeedIdLength GetSeedIdLength(void) const { return static_cast<SeedIdLength>(mControl & kSeedIdLengthMask); }
 
     /**
      * This method sets the MPL Seed Id Length value.

src/core/thread/csl_tx_scheduler.cpp

@@ -151,7 +151,7 @@ void CslTxScheduler::RescheduleCslTx(void)
     mCslTxChild = bestChild;
 }
 
-uint32_t CslTxScheduler::GetNextCslTransmissionDelay(const Child &aChild, uint64_t aRadioNow)
+uint32_t CslTxScheduler::GetNextCslTransmissionDelay(const Child &aChild, uint64_t aRadioNow) const
 {
     uint32_t delay;
     uint16_t period_offset = (aRadioNow / kUsPerTenSymbols) % aChild.GetCslPeriod();

src/core/thread/csl_tx_scheduler.hpp

@@ -190,7 +190,7 @@ private:
     void InitFrameRequestAhead(void);
     void RescheduleCslTx(void);
 
-    uint32_t GetNextCslTransmissionDelay(const Child &aChild, uint64_t aRadioNow);
+    uint32_t GetNextCslTransmissionDelay(const Child &aChild, uint64_t aRadioNow) const;
 
     // Callbacks from `Mac`
     otError HandleFrameRequest(Mac::TxFrame &aFrame);

src/core/thread/mle.cpp

@@ -1011,7 +1011,7 @@ exit:
     return error;
 }
 
-otError Mle::AppendSourceAddress(Message &aMessage)
+otError Mle::AppendSourceAddress(Message &aMessage) const
 {
     return Tlv::AppendUint16Tlv(aMessage, Tlv::kSourceAddress, GetRloc16());
 }

src/core/thread/mle.hpp

@@ -935,7 +935,7 @@ protected:
      * @retval OT_ERROR_NO_BUFS  Insufficient buffers available to append the Source Address TLV.
      *
      */
-    otError AppendSourceAddress(Message &aMessage);
+    otError AppendSourceAddress(Message &aMessage) const;
 
     /**
      * This method appends a Mode TLV to a message.

src/core/thread/network_data_leader_ftd.cpp

@@ -963,7 +963,7 @@ exit:
     return error;
 }
 
-otError Leader::AllocateServiceId(uint8_t &aServiceId)
+otError Leader::AllocateServiceId(uint8_t &aServiceId) const
 {
     otError error = OT_ERROR_NOT_FOUND;
     uint8_t serviceId;

src/core/thread/network_data_leader_ftd.hpp

@@ -215,7 +215,7 @@ private:
     otError AddService(const ServiceTlv &aService, ChangedFlags &aChangedFlags);
     otError AddServer(const ServerTlv &aServer, ServiceTlv &aDstService, ChangedFlags &aChangedFlags);
 
-    otError AllocateServiceId(uint8_t &aServiceId);
+    otError AllocateServiceId(uint8_t &aServiceId) const;
 
     otError AllocateContextId(uint8_t &aConextId);
     void    FreeContextId(uint8_t aContextId);

src/core/utils/channel_monitor.cpp

@@ -202,7 +202,7 @@ void ChannelMonitor::LogResults(void)
 #endif
 }
 
-Mac::ChannelMask ChannelMonitor::FindBestChannels(const Mac::ChannelMask &aMask, uint16_t &aOccupancy)
+Mac::ChannelMask ChannelMonitor::FindBestChannels(const Mac::ChannelMask &aMask, uint16_t &aOccupancy) const
 {
     uint8_t          channel;
     Mac::ChannelMask bestMask;

src/core/utils/channel_monitor.hpp

@@ -183,7 +183,7 @@ public:
      *             channel with the same occupancy rate value.
      *
      */
-    Mac::ChannelMask FindBestChannels(const Mac::ChannelMask &aMask, uint16_t &aOccupancy);
+    Mac::ChannelMask FindBestChannels(const Mac::ChannelMask &aMask, uint16_t &aOccupancy) const;
 
 private:
     enum