Merge bitcoin/bitcoin#21939: refactor: Replace memset calls with array initialization

1c9255c7dd2d4f12bfb508bcc8d123a6354d8842 refactor: Replace memset calls with array initialization (João Barbosa)

Pull request description:

  Follow up to https://github.com/bitcoin/bitcoin/pull/21905#pullrequestreview-657045699.

ACKs for top commit:
  laanwj:
    re-ACK 1c9255c7dd2d4f12bfb508bcc8d123a6354d8842
  Crypt-iQ:
    Code review ACK 1c9255c7dd2d4f12bfb508bcc8d123a6354d8842

Tree-SHA512: 4b61dec2094f4781ef1c0427ee3bda3cfea12111274eebc7bc40a84f261d9c1681dd0860c57200bea2456588e44e8e0aecd18545c25f1f1250dd331ab7d05f28

2 files changed, 5 insertions, 14 deletions

diff --git a/src/protocol.cpp b/src/protocol.cpp
index 2f77ec18e6..2e70b41e4c 100644
--- a/src/protocol.cpp
+++ b/src/protocol.cpp
@@ -87,25 +87,16 @@ const static std::string allNetMessageTypes[] = {
 };
 const static std::vector<std::string> allNetMessageTypesVec(std::begin(allNetMessageTypes), std::end(allNetMessageTypes));
 
-CMessageHeader::CMessageHeader()
-{
-    memset(pchMessageStart, 0, MESSAGE_START_SIZE);
-    memset(pchCommand, 0, sizeof(pchCommand));
-    memset(pchChecksum, 0, CHECKSUM_SIZE);
-}
-
 CMessageHeader::CMessageHeader(const MessageStartChars& pchMessageStartIn, const char* pszCommand, unsigned int nMessageSizeIn)
 {
     memcpy(pchMessageStart, pchMessageStartIn, MESSAGE_START_SIZE);
 
-    // Copy the command name, zero-padding to COMMAND_SIZE bytes
+    // Copy the command name
     size_t i = 0;
     for (; i < COMMAND_SIZE && pszCommand[i] != 0; ++i) pchCommand[i] = pszCommand[i];
     assert(pszCommand[i] == 0); // Assert that the command name passed in is not longer than COMMAND_SIZE
-    for (; i < COMMAND_SIZE; ++i) pchCommand[i] = 0;
 
     nMessageSize = nMessageSizeIn;
-    memset(pchChecksum, 0, CHECKSUM_SIZE);
 }
 
 std::string CMessageHeader::GetCommand() const
diff --git a/src/protocol.h b/src/protocol.h
index c73484bdf6..aaa9f1df40 100644
--- a/src/protocol.h
+++ b/src/protocol.h
@@ -38,7 +38,7 @@ public:
     static constexpr size_t HEADER_SIZE = MESSAGE_START_SIZE + COMMAND_SIZE + MESSAGE_SIZE_SIZE + CHECKSUM_SIZE;
     typedef unsigned char MessageStartChars[MESSAGE_START_SIZE];
 
-    explicit CMessageHeader();
+    explicit CMessageHeader() = default;
 
     /** Construct a P2P message header from message-start characters, a command and the size of the message.
      * @note Passing in a `pszCommand` longer than COMMAND_SIZE will result in a run-time assertion error.
@@ -50,10 +50,10 @@ public:
 
     SERIALIZE_METHODS(CMessageHeader, obj) { READWRITE(obj.pchMessageStart, obj.pchCommand, obj.nMessageSize, obj.pchChecksum); }
 
-    char pchMessageStart[MESSAGE_START_SIZE];
-    char pchCommand[COMMAND_SIZE];
+    char pchMessageStart[MESSAGE_START_SIZE]{};
+    char pchCommand[COMMAND_SIZE]{};
     uint32_t nMessageSize{std::numeric_limits<uint32_t>::max()};
-    uint8_t pchChecksum[CHECKSUM_SIZE];
+    uint8_t pchChecksum[CHECKSUM_SIZE]{};
 };
 
 /**