Refactor View classes:

The View hierarchy of classes is reorganized to include new
classes with member functions moved and renamed, to solve
defects in the original design:

OpenView accumulates raw state and tx changes and
can be applied to the base. ApplyView accumulates changes
for a single transaction, including metadata, and can be
applied to an OpenView. The Sandbox allows changes with
the option to apply or throw them out. The PaymentSandbox
provides a sandbox with account credit deferral.

Call sites are changed to use the class appropriate for
the task.

src/ripple/ledger/impl/ApplyViewBase.cpp

@@ -0,0 +1,163 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of rippled: https://github.com/ripple/rippled
+    Copyright (c) 2012, 2013 Ripple Labs Inc.
+
+    Permission to use, copy, modify, and/or distribute this software for any
+    purpose  with  or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#include <BeastConfig.h>
+#include <ripple/ledger/detail/ApplyViewBase.h>
+#include <ripple/basics/contract.h>
+
+namespace ripple {
+namespace detail {
+
+ApplyViewBase::ApplyViewBase(
+    ReadView const* base,
+        ApplyFlags flags)
+    : flags_ (flags)
+    , base_ (base)
+{
+}
+
+//---
+
+LedgerInfo const&
+ApplyViewBase::info() const
+{
+    return base_->info();
+}
+
+Fees const&
+ApplyViewBase::fees() const
+{
+    return base_->fees();
+}
+
+bool
+ApplyViewBase::exists (Keylet const& k) const
+{
+    return items_.exists(*base_, k);
+}
+
+auto
+ApplyViewBase::succ (key_type const& key,
+    boost::optional<key_type> last) const ->
+        boost::optional<key_type>
+{
+    return items_.succ(*base_, key, last);
+}
+
+std::shared_ptr<SLE const>
+ApplyViewBase::read (Keylet const& k) const
+{
+    return items_.read(*base_, k);
+}
+
+auto
+ApplyViewBase::txsBegin() const ->
+    std::unique_ptr<txs_type::iter_base>
+{
+    return base_->txsBegin();
+}
+
+auto
+ApplyViewBase::txsEnd() const ->
+    std::unique_ptr<txs_type::iter_base>
+{
+    return base_->txsEnd();
+}
+
+bool
+ApplyViewBase::txExists (key_type const& key) const
+{
+    return base_->txExists(key);
+}
+
+auto
+ApplyViewBase::txRead(
+    key_type const& key) const ->
+        tx_type
+{
+    return base_->txRead(key);
+}
+
+//---
+
+ApplyFlags
+ApplyViewBase::flags() const
+{
+    return flags_;
+}
+
+std::shared_ptr<SLE>
+ApplyViewBase::peek (Keylet const& k)
+{
+    return items_.peek(*base_, k);
+}
+
+void
+ApplyViewBase::erase(
+    std::shared_ptr<SLE> const& sle)
+{
+    items_.erase(*base_, sle);
+}
+
+void
+ApplyViewBase::insert(
+    std::shared_ptr<SLE> const& sle)
+{
+    items_.insert(*base_, sle);
+}
+
+void
+ApplyViewBase::update(
+    std::shared_ptr<SLE> const& sle)
+{
+    items_.update(*base_, sle);
+}
+
+//---
+
+void
+ApplyViewBase::rawErase(
+    std::shared_ptr<SLE> const& sle)
+{
+    items_.rawErase(*base_, sle);
+}
+
+void
+ApplyViewBase::rawInsert(
+    std::shared_ptr<SLE> const& sle)
+{
+    items_.insert(*base_, sle);
+}
+
+void
+ApplyViewBase::rawReplace(
+    std::shared_ptr<SLE> const& sle)
+{
+    items_.replace(*base_, sle);
+}
+
+void
+ApplyViewBase::rawDestroyXRP(
+    std::uint64_t feeDrops)
+{
+    items_.destroyXRP(feeDrops);
+}
+
+} // detail
+} // ripple