Make router take up less space for verbs

As is, the router designates routes for every possible boost verb, of
which there are 31.  In bmcweb, we only make use of 6 of those verbs, so
that ends up being quite a bit of wasted space and cache non-locality.

This commit invents a new enum class for declaring a subset of boost
verbs that we support, and a mapping between bmcweb verbs and boost
verbs.

Then it walks through and updates the router to support converting one
to another.

Tested:
Unit Tested
Redfish Service Validator performed on future commit

Signed-off-by: Ed Tanous <edtanous@google.com>
Signed-off-by: Edward Lee <edwarddl@google.com>
Change-Id: I3c89e896c632a5d4134dbd08a30b313c12a60de6

1 files changed, 27 insertions, 18 deletions

diff --git a/http/routing.hpp b/http/routing.hpp
index 870a62c9ed..6c393ab33b 100644
--- a/http/routing.hpp
+++ b/http/routing.hpp
@@ -9,6 +9,7 @@
 #include "privileges.hpp"
 #include "sessions.hpp"
 #include "utility.hpp"
+#include "verb.hpp"
 #include "websocket.hpp"
 
 #include <async_resp.hpp>
@@ -20,6 +21,7 @@
 #include <cstdlib>
 #include <limits>
 #include <memory>
+#include <optional>
 #include <tuple>
 #include <utility>
 #include <vector>
@@ -27,13 +29,7 @@
 namespace crow
 {
 
-// Note, this is an imperfect abstraction.  There are a lot of verbs that we
-// use memory for, but are basically unused by most implementations.
-// Ideally we would have a list of verbs that we do use, and only index in
-// to a smaller array of those, but that would require a translation from
-// boost::beast::http::verb, to the bmcweb index.
-static constexpr size_t maxVerbIndex =
-    static_cast<size_t>(boost::beast::http::verb::patch);
+static constexpr size_t maxVerbIndex = static_cast<size_t>(HttpVerb::Max) - 1U;
 
 // MaxVerb + 1 is designated as the "not found" verb.  It is done this way
 // to keep the BaseRule as a single bitfield (thus keeping the struct small)
@@ -107,8 +103,7 @@ class BaseRule
         return false;
     }
 
-    size_t methodsBitfield{
-        1 << static_cast<size_t>(boost::beast::http::verb::get)};
+    size_t methodsBitfield{1 << static_cast<size_t>(HttpVerb::Get)};
     static_assert(std::numeric_limits<decltype(methodsBitfield)>::digits >
                       methodNotAllowedIndex,
                   "Not enough bits to store bitfield");
@@ -445,7 +440,11 @@ struct RuleParameterTraits
     self_t& methods(boost::beast::http::verb method)
     {
         self_t* self = static_cast<self_t*>(this);
-        self->methodsBitfield = 1U << static_cast<size_t>(method);
+        std::optional<HttpVerb> verb = httpVerbFromBoost(method);
+        if (verb)
+        {
+            self->methodsBitfield = 1U << static_cast<size_t>(*verb);
+        }
         return *self;
     }
 
@@ -454,7 +453,11 @@ struct RuleParameterTraits
     {
         self_t* self = static_cast<self_t*>(this);
         methods(argsMethod...);
-        self->methodsBitfield |= 1U << static_cast<size_t>(method);
+        std::optional<HttpVerb> verb = httpVerbFromBoost(method);
+        if (verb)
+        {
+            self->methodsBitfield |= 1U << static_cast<size_t>(*verb);
+        }
         return *self;
     }
 
@@ -1210,7 +1213,12 @@ class Router
     {
         FindRouteResponse findRoute;
 
-        size_t reqMethodIndex = static_cast<size_t>(req.method());
+        std::optional<HttpVerb> verb = httpVerbFromBoost(req.method());
+        if (!verb)
+        {
+            return findRoute;
+        }
+        size_t reqMethodIndex = static_cast<size_t>(*verb);
         // Check to see if this url exists at any verb
         for (size_t perMethodIndex = 0; perMethodIndex <= maxVerbIndex;
              perMethodIndex++)
@@ -1227,8 +1235,8 @@ class Router
             {
                 findRoute.allowHeader += ", ";
             }
-            findRoute.allowHeader += boost::beast::http::to_string(
-                static_cast<boost::beast::http::verb>(perMethodIndex));
+            HttpVerb thisVerb = static_cast<HttpVerb>(perMethodIndex);
+            findRoute.allowHeader += httpVerbToString(thisVerb);
             if (perMethodIndex == reqMethodIndex)
             {
                 findRoute.route = route;
@@ -1240,14 +1248,14 @@ class Router
     template <typename Adaptor>
     void handleUpgrade(const Request& req, Response& res, Adaptor&& adaptor)
     {
-        if (static_cast<size_t>(req.method()) >= perMethods.size())
+        std::optional<HttpVerb> verb = httpVerbFromBoost(req.method());
+        if (!verb || static_cast<size_t>(*verb) >= perMethods.size())
         {
             res.result(boost::beast::http::status::not_found);
             res.end();
             return;
         }
-
-        PerMethod& perMethod = perMethods[static_cast<size_t>(req.method())];
+        PerMethod& perMethod = perMethods[static_cast<size_t>(*verb)];
         Trie& trie = perMethod.trie;
         std::vector<BaseRule*>& rules = perMethod.rules;
 
@@ -1309,7 +1317,8 @@ class Router
     void handle(Request& req,
                 const std::shared_ptr<bmcweb::AsyncResp>& asyncResp)
     {
-        if (static_cast<size_t>(req.method()) >= perMethods.size())
+        std::optional<HttpVerb> verb = httpVerbFromBoost(req.method());
+        if (!verb || static_cast<size_t>(*verb) >= perMethods.size())
         {
             asyncResp->res.result(boost::beast::http::status::not_found);
             return;