add WrappedSLEBase

include/xrpl/ledger/helpers/WrappedSLEBase.h

@@ -0,0 +1,109 @@
+#pragma once
+
+#include <xrpl/protocol/STLedgerEntry.h>
+
+#include <memory>
+#include <stdexcept>
+
+namespace xrpl {
+
+class ReadView;
+class ApplyView;
+
+/**
+ * Base class for all ledger entry view classes.
+ *
+ * Provides common functionality for existence checking and raw SLE access.
+ * Supports both read-only (ReadView) and read-write (ApplyView) contexts.
+ *
+ * Derived classes should provide domain-specific accessors that hide
+ * implementation details of the underlying ledger entry format.
+ */
+class WrappedSLEBase
+{
+public:
+    virtual ~WrappedSLEBase() = default;
+
+    /** Returns true if the ledger entry exists */
+    bool
+    exists() const
+    {
+        return sle_ != nullptr;
+    }
+
+    /** Explicit conversion to bool for convenient existence checking */
+    explicit
+    operator bool() const
+    {
+        return exists();
+    }
+
+    /** Returns the underlying SLE for raw access when needed */
+    std::shared_ptr<SLE const> const&
+    sle() const
+    {
+        return sle_;
+    }
+
+    /** Returns the read view (always available) */
+    ReadView const*
+    readView() const
+    {
+        return readView_;
+    }
+
+    /** Returns true if this wrapper supports write operations */
+    bool
+    canModify() const
+    {
+        return applyView_ != nullptr;
+    }
+
+    /** Returns the apply view for write operations
+     *
+     * @throws std::logic_error if called in a read-only context
+     */
+    ApplyView*
+    applyView() const
+    {
+        if (!applyView_)
+        {
+            throw std::logic_error("Cannot access ApplyView in read-only context");
+        }
+        return applyView_;
+    }
+
+    STLedgerEntry const*
+    operator->() const
+    {
+        return sle_.get();
+    }
+
+    STLedgerEntry const&
+    operator*() const
+    {
+        return *sle_;
+    }
+
+protected:
+    WrappedSLEBase() = default;
+
+    /** Constructor for read-only context (ReadView) */
+    explicit WrappedSLEBase(std::shared_ptr<SLE const> sle, ReadView const* view)
+        : sle_(std::move(sle)), readView_(view), applyView_(nullptr)
+    {
+    }
+
+    /** Constructor for read-write context (ApplyView) */
+    explicit WrappedSLEBase(std::shared_ptr<SLE const> sle, ApplyView* view)
+        : sle_(std::move(sle)), readView_(view), applyView_(view)
+    {
+        // ApplyView inherits from ReadView, so we can use it for both
+    }
+
+    std::shared_ptr<SLE const> sle_;
+    ReadView const* readView_;
+    ApplyView* applyView_;  // nullptr for read-only contexts
+};
+
+}  // namespace xrpl