Remove virtual dispatch from LogData (#13123)

This addresses a performance regression added by #13059.

Malformed pre-transaction logging introduced an extra virtual data
interface on the normal access log path. That made every completed
transaction pay for indirection that is only needed for rare
protocol-layer failures.

This replaces the virtual hierarchy with a concrete composed
TransactionLogData wrapper. This keeps LogAccess using one data object
while routing the common HttpSM path through direct getters and falling
back to owned pre-transaction data only when no HttpSM exists.

Author: bneradt

include/proxy/PreTransactionLogData.h

@@ -24,7 +24,9 @@
 
 #pragma once
 
-#include "proxy/logging/TransactionLogData.h"
+#include "proxy/Milestones.h"
+#include "proxy/hdrs/HTTP.h"
+#include "tscore/ink_inet.h"
 
 #include <string>
 
@@ -36,160 +38,21 @@
  * copied request and session metadata needed to emit a best-effort
  * transaction log entry for those failures.
  *
- * Unlike TransactionLogData (which reads from a live HttpSM), this class
- * owns its milestones, addresses, and strings because the originating
- * stream is about to be destroyed.
+ * This class owns its milestones, addresses, and strings because the
+ * originating stream is about to be destroyed.
  */
-class PreTransactionLogData : public TransactionLogData
+class PreTransactionLogData
 {
 public:
   PreTransactionLogData() = default;
 
-  ~PreTransactionLogData() override
+  ~PreTransactionLogData()
   {
     if (owned_client_request.valid()) {
       owned_client_request.destroy();
     }
   }
 
-  // ===== Milestones =====
-
-  TransactionMilestones const *
-  get_milestones() const override
-  {
-    return &owned_milestones;
-  }
-
-  // ===== Headers =====
-
-  HTTPHdr *
-  get_client_request() const override
-  {
-    if (owned_client_request.valid()) {
-      return const_cast<HTTPHdr *>(&owned_client_request);
-    }
-    return nullptr;
-  }
-
-  // ===== Client request URL / path =====
-
-  const char *
-  get_client_req_url_str() const override
-  {
-    return owned_url.empty() ? nullptr : owned_url.c_str();
-  }
-  int
-  get_client_req_url_len() const override
-  {
-    return static_cast<int>(owned_url.size());
-  }
-  const char *
-  get_client_req_url_path_str() const override
-  {
-    return owned_path.empty() ? nullptr : owned_path.c_str();
-  }
-  int
-  get_client_req_url_path_len() const override
-  {
-    return static_cast<int>(owned_path.size());
-  }
-
-  // ===== Client addressing =====
-
-  sockaddr const *
-  get_client_addr() const override
-  {
-    return &owned_client_addr.sa;
-  }
-  sockaddr const *
-  get_client_src_addr() const override
-  {
-    return &owned_client_src_addr.sa;
-  }
-  sockaddr const *
-  get_client_dst_addr() const override
-  {
-    return &owned_client_dst_addr.sa;
-  }
-  uint16_t
-  get_client_port() const override
-  {
-    return m_client_port;
-  }
-
-  // ===== Squid codes =====
-
-  SquidLogCode
-  get_log_code() const override
-  {
-    return m_log_code;
-  }
-  SquidHitMissCode
-  get_hit_miss_code() const override
-  {
-    return m_hit_miss_code;
-  }
-  SquidHierarchyCode
-  get_hier_code() const override
-  {
-    return m_hier_code;
-  }
-
-  // ===== Transaction identifiers =====
-
-  int64_t
-  get_connection_id() const override
-  {
-    return m_connection_id;
-  }
-  int
-  get_transaction_id() const override
-  {
-    return m_transaction_id;
-  }
-
-  // ===== Protocol info =====
-
-  const char *
-  get_client_protocol() const override
-  {
-    return owned_client_protocol_str.empty() ? nullptr : owned_client_protocol_str.c_str();
-  }
-
-  // ===== Connection flags =====
-
-  bool
-  get_client_connection_is_ssl() const override
-  {
-    return m_client_connection_is_ssl;
-  }
-
-  // ===== Server transaction count =====
-
-  int64_t
-  get_server_transact_count() const override
-  {
-    return m_server_transact_count;
-  }
-
-  // ===== Fallback fields for pre-transaction logging =====
-
-  std::string_view
-  get_method() const override
-  {
-    return owned_method;
-  }
-  std::string_view
-  get_scheme() const override
-  {
-    return owned_scheme;
-  }
-  std::string_view
-  get_client_protocol_str() const override
-  {
-    return owned_client_protocol_str;
-  }
-
   // ===== Owned backing storage (public for ProxyTransaction to populate). =====
 
   HTTPHdr               owned_client_request;

include/proxy/http/CompletedTransactionLogData.h

@@ -43,7 +43,7 @@
   @section example Example usage of the API
 
   @code
-  // Populate a LogData (e.g. TransactionLogData or PreTransactionLogData), then:
+  // Populate a TransactionLogData, then:
   LogAccess entry(data);
   int ret = Log::access(&entry);
   @endcode