DataFlash: remove unused ReadBlock method

libraries/DataFlash/DataFlash_Backend.h

@@ -141,8 +141,6 @@ protected:
     /*
       read a block
     */
-    virtual bool ReadBlock(void *pkt, uint16_t size) = 0;
-
     virtual bool WriteBlockCheckStartupMessages();
     virtual void WriteMoreStartupMessages();
     virtual void push_log_blocks();

libraries/DataFlash/DataFlash_File.cpp

@@ -580,24 +580,6 @@ bool DataFlash_File::_WritePrioritisedBlock(const void *pBuffer, uint16_t size,
     return true;
 }
 
-/*
-  read a packet. The header bytes have already been read.
-*/
-bool DataFlash_File::ReadBlock(void *pkt, uint16_t size)
-{
-    if (_read_fd == -1 || !_initialised || _open_error) {
-        return false;
-    }
-
-    memset(pkt, 0, size);
-    if (::read(_read_fd, pkt, size) != size) {
-        return false;
-    }
-    _read_offset += size;
-    return true;
-}
-
-
 /*
   find the highest log number
  */

libraries/DataFlash/DataFlash_File.h

@@ -81,11 +81,6 @@ private:
 
     uint16_t _cached_oldest_log;
 
-    /*
-      read a block
-    */
-    bool ReadBlock(void *pkt, uint16_t size) override;
-
     uint16_t _log_num_from_list_entry(const uint16_t list_entry);
 
     // possibly time-consuming preparations handling

libraries/DataFlash/DataFlash_File_sd.cpp

@@ -501,24 +501,6 @@ bool DataFlash_File::_WritePrioritisedBlock(const void *pBuffer, uint16_t size,
     return true;
 }
 
-/*
-  read a packet. The header bytes have already been read.
-*/
-bool DataFlash_File::ReadBlock(void *pkt, uint16_t size)
-{
-    if (!(_read_fd) || !_initialised || _open_error) {
-        return false;
-    }
-
-    memset(pkt, 0, size);
-    if (_read_fd.read(pkt, size) != size) {
-        return false;
-    }
-    _read_offset += size;
-    return true;
-}
-
-
 /*
   find the highest log number
  */

libraries/DataFlash/DataFlash_File_sd.h

@@ -78,11 +78,6 @@ private:
     uint16_t _cached_oldest_log;
     uint16_t _last_oldest_log;
 
-    /*
-      read a block
-    */
-    bool ReadBlock(void *pkt, uint16_t size) override;
-
     uint16_t _log_num_from_list_entry(const uint16_t list_entry);
 
     // possibly time-consuming preparations handling

libraries/DataFlash/DataFlash_MAVLink.h

@@ -173,9 +173,6 @@ private:
     uint16_t start_new_log(void) override {
         return 0;
     }
-    bool ReadBlock(void *pkt, uint16_t size) override {
-        return false;
-    }
     // performance counters
     AP_HAL::Util::perf_counter_t  _perf_errors;
     AP_HAL::Util::perf_counter_t  _perf_packing;