Simplify code using if constexpr:

Also simplify msig construction

src/ripple/protocol/Feature.h

@@ -129,15 +129,12 @@ class FeatureBitset
 {
     using base = std::bitset<detail::FeatureCollections::numFeatures()>;
 
-    void initFromFeatures()
-    {
-    }
-
     template<class... Fs>
     void initFromFeatures(uint256 const& f, Fs&&... fs)
     {
         set(f);
-        initFromFeatures(std::forward<Fs>(fs)...);
+        if constexpr (sizeof...(fs) > 0)
+            initFromFeatures(std::forward<Fs>(fs)...);
     }
 
 public:

src/test/app/Path_test.cpp

@@ -83,25 +83,14 @@ stpath_append_one (STPath& st,
         boost::none, book.currency, book.account }));
 }
 
-inline
-void
-stpath_append (STPath& st)
-{
-}
-
 template <class T, class... Args>
 void
 stpath_append (STPath& st,
     T const& t, Args const&... args)
 {
     stpath_append_one(st, t);
-    stpath_append(st, args...);
-}
-
-inline
-void
-stpathset_append (STPathSet& st)
-{
+    if constexpr (sizeof...(args) > 0)
+        stpath_append(st, args...);
 }
 
 template <class... Args>
@@ -110,7 +99,8 @@ stpathset_append(STPathSet& st,
     STPath const& p, Args const&... args)
 {
     st.push_back(p);
-    stpathset_append(st, args...);
+    if constexpr (sizeof...(args) > 0)
+        stpathset_append(st, args...);
 }
 
 } // detail

src/test/jtx/Env.h

@@ -548,14 +548,6 @@ private:
         STAmount const& amount,
             Account const& account);
 
-    // If you get an error here it means
-    // you're calling fund with no accounts
-    inline
-    void
-    fund (STAmount const&)
-    {
-    }
-
     void
     fund_arg (STAmount const& amount,
         Account const& account)
@@ -605,7 +597,8 @@ public:
         Arg const& arg, Args const&... args)
     {
         fund_arg (amount, arg);
-        fund (amount, args...);
+        if constexpr (sizeof...(args) > 0)
+            fund(amount, args...);
     }
 
     /** Establish trust lines.

src/test/jtx/PathSet.h

@@ -69,9 +69,8 @@ public:
     Path& push_back (STPathElement const& pe);
     Json::Value json () const;
  private:
-    Path& addHelper (){return *this;}
     template <class First, class... Rest>
-    Path& addHelper (First&& first, Rest&&... rest);
+    void addHelper (First&& first, Rest&&... rest);
 };
 
 inline Path& Path::push_back (STPathElement const& pe)
@@ -95,10 +94,11 @@ Path& Path::push_back (jtx::Account const& account)
 }
 
 template <class First, class... Rest>
-Path& Path::addHelper (First&& first, Rest&&... rest)
+void Path::addHelper (First&& first, Rest&&... rest)
 {
     push_back (std::forward<First> (first));
-    return addHelper (std::forward<Rest> (rest)...);
+    if constexpr (sizeof...(rest) > 0)
+        addHelper(std::forward<Rest>(rest)...);
 }
 
 inline
@@ -130,15 +130,12 @@ public:
         return v;
     }
 private:
-    PathSet& addHelper ()
-    {
-        return *this;
-    }
     template <class First, class... Rest>
-    PathSet& addHelper (First first, Rest... rest)
+    void addHelper (First first, Rest... rest)
     {
         paths.emplace_back (std::move (first.path));
-        return addHelper (std::move (rest)...);
+        if constexpr (sizeof...(rest) > 0)
+            addHelper(std::move(rest)...);
     }
 };
 

src/test/jtx/flags.h

@@ -53,12 +53,6 @@ protected:
     std::uint32_t mask_;
 
 private:
-    inline
-    void
-    set_args()
-    {
-    }
-
     void
     set_args (std::uint32_t flag)
     {
@@ -85,7 +79,9 @@ private:
     set_args (std::uint32_t flag,
         Args... args)
     {
-        set_args(flag, args...);
+        set_args(flag);
+        if constexpr (sizeof...(args))
+            set_args(args...);
     }
 
 protected:

src/test/jtx/multisign.h

@@ -96,48 +96,14 @@ public:
     msig (std::vector<Reg> signers_);
 
     template <class AccountType, class... Accounts>
-    msig (AccountType&& a0, Accounts&&... aN)
-        : msig(make_vector(
-            std::forward<AccountType>(a0),
-                std::forward<Accounts>(aN)...))
+    explicit msig(AccountType&& a0, Accounts&&... aN)
+        : msig{std::vector<Reg>{std::forward<AccountType>(a0),
+                                std::forward<Accounts>(aN)...}}
     {
     }
 
     void
     operator()(Env&, JTx& jt) const;
-
-private:
-    template <class AccountType>
-    static
-    void
-    helper (std::vector<Reg>& v,
-        AccountType&& account)
-    {
-        v.emplace_back(std::forward<
-            Reg>(account));
-    }
-
-    template <class AccountType, class... Accounts>
-    static
-    void
-    helper (std::vector<Reg>& v,
-        AccountType&& a0, Accounts&&... aN)
-    {
-        helper(v, std::forward<AccountType>(a0));
-        helper(v, std::forward<Accounts>(aN)...);
-    }
-
-    template <class... Accounts>
-    static
-    std::vector<Reg>
-    make_vector(Accounts&&... signers)
-    {
-        std::vector<Reg> v;
-        v.reserve(sizeof...(signers));
-        helper(v, std::forward<
-            Accounts>(signers)...);
-        return v;
-    }
 };
 
 //------------------------------------------------------------------------------

src/test/jtx/paths.h

@@ -91,12 +91,6 @@ private:
     void
     append_one(BookSpec const& book);
 
-    inline
-    void
-    append()
-    {
-    }
-
     template <class T, class... Args>
     void
     append (T const& t, Args const&... args);
@@ -114,7 +108,8 @@ void
 path::append (T const& t, Args const&... args)
 {
     append_one(t);
-    append(args...);
+    if constexpr (sizeof...(args) > 0)
+        append(args...);
 }
 
 } // jtx

src/test/jtx/require.h

@@ -30,12 +30,6 @@ namespace jtx {
 
 namespace detail {
 
-inline
-void
-require_args (requires_t& vec)
-{
-}
-
 template <class Cond, class... Args>
 inline
 void
@@ -43,7 +37,8 @@ require_args (requires_t& vec,
     Cond const& cond, Args const&... args)
 {
     vec.push_back(cond);
-    require_args(vec, args...);
+    if constexpr (sizeof...(args) > 0)
+        require_args(vec, args...);
 }
 
 } // detail

src/test/jtx/ticket.h

@@ -64,13 +64,6 @@ create_arg (boost::optional<Account>&,
     opt = value;
 }
 
-inline
-void
-create_args (boost::optional<Account>&,
-    boost::optional<std::uint32_t>&)
-{
-}
-
 template<class Arg, class... Args>
 void
 create_args(boost::optional<Account>& account_opt,
@@ -78,7 +71,8 @@ create_args(boost::optional<Account>& account_opt,
         Arg const& arg, Args const&... args)
 {
     create_arg(account_opt, expire_opt, arg);
-    create_args(account_opt, expire_opt, args...);
+    if constexpr (sizeof...(args))
+        create_args(account_opt, expire_opt, args...);
 }
 
 } // detail
@@ -91,7 +85,8 @@ create (Account const& account,
 {
     boost::optional<Account> target;
     boost::optional<std::uint32_t> expire;
-    detail::create_args(target, expire, args...);
+    if constexpr (sizeof...(args) > 0)
+        detail::create_args(target, expire, args...);
     return detail::create(
         account, target, expire);
 }