Cleanup: Use enum class (#12249)

This pull request converts non-class enums to enum classes.
There are still many non-class enums not addressed in this pull request.
However, since the changes have grown quite large, I'm submitting it at this point.

Author: hnakamur

doc/admin-guide/files/records.yaml.en.rst

@@ -1730,7 +1730,7 @@ Origin Server Connect Attempts
    Set a limit for the number of concurrent connections to an upstream server group. A value of
    ``0`` disables checking. If a transaction attempts to connect to a group which already has the
    maximum number of concurrent connections a 503
-   (``HTTP_STATUS_SERVICE_UNAVAILABLE``) error response is sent to the user agent. To configure
+   (``HTTPStatus::SERVICE_UNAVAILABLE``) error response is sent to the user agent. To configure
 
    Upstream server group definition
       See :ts:cv:`proxy.config.http.per_server.connection.match`.

doc/developer-guide/api/functions/TSHttpTxnServerRespGet.en.rst

@@ -52,5 +52,5 @@ calls to retrieve information from the header.
       if (TS_SUCCESS == TSHttpTxnServerRespGet(tnx, &resp_heap, &resp_hdr)) {
          return TSHttpHdrStatusGet(resp_headp, resp_hdr);
       }
-      return HTTP_STATUS_NONE;
+      return HTTPStatus::NONE;
    }

doc/developer-guide/core-architecture/heap.en.rst

@@ -30,29 +30,32 @@ Classes
    This is the abstract base class for objects allocated in a :class:`HdrHeap`. This allows updating
    objects in a heap in a generic way, without having to locate all of the pointers to the objects.
 
-   The type of an instance stored in a heap must be one of the following values.
+.. class:: HdrHeapObjType
 
-   .. enumerator:: HDR_HEAP_OBJ_EMPTY = 0
+   This is the enum class for type of a :class:`HdrHeapObjImpl`.
+   The type of a :class:`HdrHeapObjImpl` instance stored in a heap must be one of the following values.
+
+   .. enumerator:: EMPTY = 0
 
       Used to mark invalid objects, ones not yet constructed or ones that have been destroyed.
 
-   .. enumerator:: HDR_HEAP_OBJ_RAW = 1
+   .. enumerator:: RAW = 1
 
       Some sort of raw object, I have no idea.
 
-   .. enumerator:: HDR_HEAP_OBJ_URL = 2
+   .. enumerator:: URL = 2
 
       A URL object.
 
-   .. enumerator:: HDR_HEAP_OBJ_HTTP_HEADER = 3
+   .. enumerator:: HTTP_HEADER = 3
 
       The header for an HTTP request or response.
 
-   .. enumerator:: HDR_HEAP_OBJ_MIME_HEADER = 4
+   .. enumerator:: MIME_HEADER = 4
 
       A MIME header, containing MIME style fields with names and values.
 
-   .. enumerator:: HDR_HEAP_OBJ_FIELD_BLOCK = 5
+   .. enumerator:: FIELD_BLOCK = 5
 
       Who the heck knows?
 

include/iocore/cache/Cache.h

@@ -108,7 +108,7 @@ struct CacheProcessor : public Processor {
   */
   bool has_online_storage() const;
 
-  static int IsCacheEnabled();
+  static CacheInitState IsCacheEnabled();
 
   static bool IsCacheReady(CacheFragType type);
 
@@ -137,14 +137,14 @@ struct CacheProcessor : public Processor {
     return wait_for_cache;
   }
 
-  static uint32_t cache_ready;
-  static int      initialized;
-  static int      start_done;
-  static bool     clear;
-  static bool     fix;
-  static bool     check;
-  static int      start_internal_flags;
-  static int      auto_clear_flag;
+  static uint32_t       cache_ready;
+  static CacheInitState initialized;
+  static int            start_done;
+  static bool           clear;
+  static bool           fix;
+  static bool           check;
+  static int            start_internal_flags;
+  static int            auto_clear_flag;
 
   ts::VersionNumber min_stripe_version;
   ts::VersionNumber max_stripe_version;

include/iocore/cache/CacheDefs.h

@@ -28,9 +28,11 @@
 #include "tscore/Version.h"
 #include "tscore/CryptoHash.h"
 
-#define CACHE_INIT_FAILED  -1
-#define CACHE_INITIALIZING 0
-#define CACHE_INITIALIZED  1
+enum class CacheInitState : int {
+  FAILED       = -1,
+  INITIALIZING = 0,
+  INITIALIZED  = 1,
+};
 
 #define CACHE_ALT_INDEX_DEFAULT -1
 #define CACHE_ALT_REMOVED       -2
@@ -62,10 +64,10 @@ static const uint8_t CACHE_DIR_MINOR_VERSION = 0;
 #define CACHE_DEREF                  12
 #define CACHE_LOOKUP_OP              13
 
-enum CacheType {
-  CACHE_NONE_TYPE = 0, // for empty disk fragments
-  CACHE_HTTP_TYPE = 1,
-  CACHE_RTSP_TYPE = 2
+enum class CacheType {
+  NONE = 0, // for empty disk fragments
+  HTTP = 1,
+  RTSP = 2
 };
 
 // NOTE: All the failures are ODD, and one greater than the success

include/iocore/cache/HttpTransactCache.h

@@ -39,10 +39,10 @@
 static const time_t CacheHighAgeWatermark = UINT_MAX;
 struct CacheHTTPInfoVector;
 
-enum Variability_t {
-  VARIABILITY_NONE = 0,
-  VARIABILITY_SOME,
-  VARIABILITY_ALL,
+enum class Variability_t {
+  NONE = 0,
+  SOME,
+  ALL,
 };
 
 class HttpTransactCache

include/proxy/CacheControl.h

@@ -44,17 +44,17 @@ const int CC_UNSET_TIME = -1;
 //     load to verify memory allocation
 // #define CACHE_CONTROL_TIMEOUT            (HRTIME_SECOND*10)
 
-enum CacheControlType {
-  CC_INVALID = 0,
-  CC_REVALIDATE_AFTER,
-  CC_NEVER_CACHE,
-  CC_STANDARD_CACHE,
-  CC_IGNORE_NO_CACHE,
-  CC_IGNORE_CLIENT_NO_CACHE,
-  CC_IGNORE_SERVER_NO_CACHE,
-  CC_PIN_IN_CACHE,
-  CC_TTL_IN_CACHE,
-  CC_NUM_TYPES
+enum class CacheControlType {
+  INVALID = 0,
+  REVALIDATE_AFTER,
+  NEVER_CACHE,
+  STANDARD_CACHE,
+  IGNORE_NO_CACHE,
+  IGNORE_CLIENT_NO_CACHE,
+  IGNORE_SERVER_NO_CACHE,
+  PIN_IN_CACHE,
+  TTL_IN_CACHE,
+  NUM_TYPES
 };
 
 struct matcher_line;
@@ -104,7 +104,7 @@ class CacheControlRecord : public ControlBase
 {
 public:
   CacheControlRecord();
-  CacheControlType directive                  = CC_INVALID;
+  CacheControlType directive                  = CacheControlType::INVALID;
   int              time_arg                   = 0;
   int              cache_responses_to_cookies = -1;
   Result           Init(matcher_line *line_info);

include/proxy/ControlBase.h

@@ -43,18 +43,18 @@ class ControlBase
 {
 public:
   struct Modifier {
-    enum Type {
-      MOD_INVALID,
-      MOD_PORT,
-      MOD_SCHEME,
-      MOD_PREFIX,
-      MOD_SUFFIX,
-      MOD_METHOD,
-      MOD_TIME,
-      MOD_SRC_IP,
-      MOD_IPORT,
-      MOD_TAG,
-      MOD_INTERNAL,
+    enum class Type {
+      INVALID,
+      PORT,
+      SCHEME,
+      PREFIX,
+      SUFFIX,
+      METHOD,
+      TIME,
+      SRC_IP,
+      IPORT,
+      TAG,
+      INTERNAL,
     };
     /// Destructor - force virtual.
     virtual ~Modifier();

include/proxy/FetchSM.h

@@ -53,7 +53,7 @@ class FetchSM : public Continuation
     resp_buffer = new_MIOBuffer(BUFFER_SIZE_INDEX_32K);
     resp_reader = resp_buffer->alloc_reader();
     http_parser_init(&http_parser);
-    client_response_hdr.create(HTTP_TYPE_RESPONSE);
+    client_response_hdr.create(HTTPType::RESPONSE);
     SET_HANDLER(&FetchSM::fetch_handler);
   }
 

include/proxy/IPAllow.h

@@ -91,7 +91,7 @@ class IpAllow : public ConfigInfo
   using IpCategories  = std::unordered_map<std::string, swoc::IPSpace<bool>>;
 
   // indicator for whether we should be checking the acl record for src ip or dest ip
-  enum match_key_t { SRC_ADDR, DST_ADDR };
+  enum class match_key_t { SRC_ADDR, DST_ADDR };
 
   /// Token strings for configuration
   static constexpr swoc::TextView OPT_MATCH_SRC{"src_ip"};