Split StorageSlot into TransientSlot (#5239)

Co-authored-by: Hadrien Croubois <hadrien.croubois@gmail.com>

scripts/generate/templates/TransientSlot.js

@@ -0,0 +1,80 @@
+const format = require('../format-lines');
+const { TYPES } = require('./Slot.opts');
+
+const header = `\
+pragma solidity ^0.8.24;
+
+/**
+ * @dev Library for reading and writing value-types to specific transient storage slots.
+ *
+ * Transient slots are often used to store temporary values that are removed after the current transaction.
+ * This library helps with reading and writing to such slots without the need for inline assembly.
+ *
+ *  * Example reading and writing values using transient storage:
+ * \`\`\`solidity
+ * contract Lock {
+ *     using TransientSlot for *;
+ *
+ *     // Define the slot. Alternatively, use the SlotDerivation library to derive the slot.
+ *     bytes32 internal constant _LOCK_SLOT = 0xf4678858b2b588224636b8522b729e7722d32fc491da849ed75b3fdf3c84f542;
+ *
+ *     modifier locked() {
+ *         require(!_LOCK_SLOT.asBoolean().tload());
+ *
+ *         _LOCK_SLOT.asBoolean().tstore(true);
+ *         _;
+ *         _LOCK_SLOT.asBoolean().tstore(false);
+ *     }
+ * }
+ * \`\`\`
+ *
+ * TIP: Consider using this library along with {SlotDerivation}.
+ */
+`;
+
+const udvt = ({ type, name }) => `\
+/**
+ * @dev UDVT that represent a slot holding a ${type}.
+ */
+type ${name}Slot is bytes32;
+
+/**
+ * @dev Cast an arbitrary slot to a ${name}Slot.
+ */
+function as${name}(bytes32 slot) internal pure returns (${name}Slot) {
+    return ${name}Slot.wrap(slot);
+}
+`;
+
+const transient = ({ type, name }) => `\
+/**
+ * @dev Load the value held at location \`slot\` in transient storage.
+ */
+function tload(${name}Slot slot) internal view returns (${type} value) {
+    assembly ("memory-safe") {
+        value := tload(slot)
+    }
+}
+
+/**
+ * @dev Store \`value\` at location \`slot\` in transient storage.
+ */
+function tstore(${name}Slot slot, ${type} value) internal {
+    assembly ("memory-safe") {
+        tstore(slot, value)
+    }
+}
+`;
+
+// GENERATE
+module.exports = format(
+  header.trimEnd(),
+  'library TransientSlot {',
+  format(
+    [].concat(
+      TYPES.filter(type => type.isValueType).map(type => udvt(type)),
+      TYPES.filter(type => type.isValueType).map(type => transient(type)),
+    ),
+  ).trimEnd(),
+  '}',
+);