Fix .gitignore: stop tracking ignored files

backend/lib/openzeppelin-contracts/scripts/generate/format-lines.js

@@ -0,0 +1,16 @@
+function formatLines(...lines) {
+  return [...indentEach(0, lines)].join('\n') + '\n';
+}
+
+function* indentEach(indent, lines) {
+  for (const line of lines) {
+    if (Array.isArray(line)) {
+      yield* indentEach(indent + 1, line);
+    } else {
+      const padding = '    '.repeat(indent);
+      yield* line.split('\n').map(subline => (subline === '' ? '' : padding + subline));
+    }
+  }
+}
+
+module.exports = formatLines;

backend/lib/openzeppelin-contracts/scripts/generate/run.js

@@ -0,0 +1,49 @@
+#!/usr/bin/env node
+
+const cp = require('child_process');
+const fs = require('fs');
+const path = require('path');
+const format = require('./format-lines');
+
+function getVersion(path) {
+  try {
+    return fs.readFileSync(path, 'utf8').match(/\/\/ OpenZeppelin Contracts \(last updated v[^)]+\)/)[0];
+  } catch (err) {
+    return null;
+  }
+}
+
+function generateFromTemplate(file, template, outputPrefix = '') {
+  const script = path.relative(path.join(__dirname, '../..'), __filename);
+  const input = path.join(path.dirname(script), template);
+  const output = path.join(outputPrefix, file);
+  const version = getVersion(output);
+  const content = format(
+    '// SPDX-License-Identifier: MIT',
+    ...(version ? [version + ` (${file})`] : []),
+    `// This file was procedurally generated from ${input}.`,
+    '',
+    require(template),
+  );
+
+  fs.writeFileSync(output, content);
+  cp.execFileSync('prettier', ['--write', output]);
+}
+
+// Contracts
+for (const [file, template] of Object.entries({
+  'utils/math/SafeCast.sol': './templates/SafeCast.js',
+  'utils/structs/EnumerableSet.sol': './templates/EnumerableSet.js',
+  'utils/structs/EnumerableMap.sol': './templates/EnumerableMap.js',
+  'utils/Checkpoints.sol': './templates/Checkpoints.js',
+  'utils/StorageSlot.sol': './templates/StorageSlot.js',
+})) {
+  generateFromTemplate(file, template, './contracts/');
+}
+
+// Tests
+for (const [file, template] of Object.entries({
+  'utils/Checkpoints.t.sol': './templates/Checkpoints.t.js',
+})) {
+  generateFromTemplate(file, template, './test/');
+}

backend/lib/openzeppelin-contracts/scripts/generate/templates/Checkpoints.js

@@ -0,0 +1,304 @@
+const format = require('../format-lines');
+const { OPTS, LEGACY_OPTS } = require('./Checkpoints.opts.js');
+
+// TEMPLATE
+const header = `\
+pragma solidity ^0.8.0;
+
+import "./math/Math.sol";
+import "./math/SafeCast.sol";
+
+/**
+ * @dev This library defines the \`History\` struct, for checkpointing values as they change at different points in
+ * time, and later looking up past values by block number. See {Votes} as an example.
+ *
+ * To create a history of checkpoints define a variable type \`Checkpoints.History\` in your contract, and store a new
+ * checkpoint for the current transaction block using the {push} function.
+ *
+ * _Available since v4.5._
+ */
+`;
+
+const types = opts => `\
+struct ${opts.historyTypeName} {
+    ${opts.checkpointTypeName}[] ${opts.checkpointFieldName};
+}
+
+struct ${opts.checkpointTypeName} {
+    ${opts.keyTypeName} ${opts.keyFieldName};
+    ${opts.valueTypeName} ${opts.valueFieldName};
+}
+`;
+
+/* eslint-disable max-len */
+const operations = opts => `\
+/**
+ * @dev Pushes a (\`key\`, \`value\`) pair into a ${opts.historyTypeName} so that it is stored as the checkpoint.
+ *
+ * Returns previous value and new value.
+ */
+function push(
+    ${opts.historyTypeName} storage self,
+    ${opts.keyTypeName} key,
+    ${opts.valueTypeName} value
+) internal returns (${opts.valueTypeName}, ${opts.valueTypeName}) {
+    return _insert(self.${opts.checkpointFieldName}, key, value);
+}
+
+/**
+ * @dev Returns the value in the first (oldest) checkpoint with key greater or equal than the search key, or zero if there is none.
+ */
+function lowerLookup(${opts.historyTypeName} storage self, ${opts.keyTypeName} key) internal view returns (${opts.valueTypeName}) {
+    uint256 len = self.${opts.checkpointFieldName}.length;
+    uint256 pos = _lowerBinaryLookup(self.${opts.checkpointFieldName}, key, 0, len);
+    return pos == len ? 0 : _unsafeAccess(self.${opts.checkpointFieldName}, pos).${opts.valueFieldName};
+}
+
+/**
+ * @dev Returns the value in the last (most recent) checkpoint with key lower or equal than the search key, or zero if there is none.
+ */
+function upperLookup(${opts.historyTypeName} storage self, ${opts.keyTypeName} key) internal view returns (${opts.valueTypeName}) {
+    uint256 len = self.${opts.checkpointFieldName}.length;
+    uint256 pos = _upperBinaryLookup(self.${opts.checkpointFieldName}, key, 0, len);
+    return pos == 0 ? 0 : _unsafeAccess(self.${opts.checkpointFieldName}, pos - 1).${opts.valueFieldName};
+}
+
+/**
+ * @dev Returns the value in the last (most recent) checkpoint with key lower or equal than the search key, or zero if there is none.
+ *
+ * NOTE: This is a variant of {upperLookup} that is optimised to find "recent" checkpoint (checkpoints with high keys).
+ */
+function upperLookupRecent(${opts.historyTypeName} storage self, ${opts.keyTypeName} key) internal view returns (${opts.valueTypeName}) {
+    uint256 len = self.${opts.checkpointFieldName}.length;
+
+    uint256 low = 0;
+    uint256 high = len;
+
+    if (len > 5) {
+        uint256 mid = len - Math.sqrt(len);
+        if (key < _unsafeAccess(self.${opts.checkpointFieldName}, mid)._key) {
+            high = mid;
+        } else {
+            low = mid + 1;
+        }
+    }
+
+    uint256 pos = _upperBinaryLookup(self.${opts.checkpointFieldName}, key, low, high);
+
+    return pos == 0 ? 0 : _unsafeAccess(self.${opts.checkpointFieldName}, pos - 1).${opts.valueFieldName};
+}
+`;
+
+const legacyOperations = opts => `\
+/**
+ * @dev Returns the value at a given block number. If a checkpoint is not available at that block, the closest one
+ * before it is returned, or zero otherwise. Because the number returned corresponds to that at the end of the
+ * block, the requested block number must be in the past, excluding the current block.
+ */
+function getAtBlock(${opts.historyTypeName} storage self, uint256 blockNumber) internal view returns (uint256) {
+    require(blockNumber < block.number, "Checkpoints: block not yet mined");
+    uint32 key = SafeCast.toUint32(blockNumber);
+
+    uint256 len = self.${opts.checkpointFieldName}.length;
+    uint256 pos = _upperBinaryLookup(self.${opts.checkpointFieldName}, key, 0, len);
+    return pos == 0 ? 0 : _unsafeAccess(self.${opts.checkpointFieldName}, pos - 1).${opts.valueFieldName};
+}
+
+/**
+ * @dev Returns the value at a given block number. If a checkpoint is not available at that block, the closest one
+ * before it is returned, or zero otherwise. Similar to {upperLookup} but optimized for the case when the searched
+ * checkpoint is probably "recent", defined as being among the last sqrt(N) checkpoints where N is the number of
+ * checkpoints.
+ */
+function getAtProbablyRecentBlock(${opts.historyTypeName} storage self, uint256 blockNumber) internal view returns (uint256) {
+    require(blockNumber < block.number, "Checkpoints: block not yet mined");
+    uint32 key = SafeCast.toUint32(blockNumber);
+
+    uint256 len = self.${opts.checkpointFieldName}.length;
+
+    uint256 low = 0;
+    uint256 high = len;
+
+    if (len > 5) {
+        uint256 mid = len - Math.sqrt(len);
+        if (key < _unsafeAccess(self.${opts.checkpointFieldName}, mid)._blockNumber) {
+            high = mid;
+        } else {
+            low = mid + 1;
+        }
+    }
+
+    uint256 pos = _upperBinaryLookup(self.${opts.checkpointFieldName}, key, low, high);
+
+    return pos == 0 ? 0 : _unsafeAccess(self.${opts.checkpointFieldName}, pos - 1).${opts.valueFieldName};
+}
+
+/**
+ * @dev Pushes a value onto a History so that it is stored as the checkpoint for the current block.
+ *
+ * Returns previous value and new value.
+ */
+function push(${opts.historyTypeName} storage self, uint256 value) internal returns (uint256, uint256) {
+    return _insert(self.${opts.checkpointFieldName}, SafeCast.toUint32(block.number), SafeCast.toUint224(value));
+}
+
+/**
+ * @dev Pushes a value onto a History, by updating the latest value using binary operation \`op\`. The new value will
+ * be set to \`op(latest, delta)\`.
+ *
+ * Returns previous value and new value.
+ */
+function push(
+    ${opts.historyTypeName} storage self,
+    function(uint256, uint256) view returns (uint256) op,
+    uint256 delta
+) internal returns (uint256, uint256) {
+    return push(self, op(latest(self), delta));
+}
+`;
+
+const common = opts => `\
+/**
+ * @dev Returns the value in the most recent checkpoint, or zero if there are no checkpoints.
+ */
+function latest(${opts.historyTypeName} storage self) internal view returns (${opts.valueTypeName}) {
+    uint256 pos = self.${opts.checkpointFieldName}.length;
+    return pos == 0 ? 0 : _unsafeAccess(self.${opts.checkpointFieldName}, pos - 1).${opts.valueFieldName};
+}
+
+/**
+ * @dev Returns whether there is a checkpoint in the structure (i.e. it is not empty), and if so the key and value
+ * in the most recent checkpoint.
+ */
+function latestCheckpoint(${opts.historyTypeName} storage self)
+    internal
+    view
+    returns (
+        bool exists,
+        ${opts.keyTypeName} ${opts.keyFieldName},
+        ${opts.valueTypeName} ${opts.valueFieldName}
+    )
+{
+    uint256 pos = self.${opts.checkpointFieldName}.length;
+    if (pos == 0) {
+        return (false, 0, 0);
+    } else {
+        ${opts.checkpointTypeName} memory ckpt = _unsafeAccess(self.${opts.checkpointFieldName}, pos - 1);
+        return (true, ckpt.${opts.keyFieldName}, ckpt.${opts.valueFieldName});
+    }
+}
+
+/**
+ * @dev Returns the number of checkpoint.
+ */
+function length(${opts.historyTypeName} storage self) internal view returns (uint256) {
+    return self.${opts.checkpointFieldName}.length;
+}
+
+/**
+ * @dev Pushes a (\`key\`, \`value\`) pair into an ordered list of checkpoints, either by inserting a new checkpoint,
+ * or by updating the last one.
+ */
+function _insert(
+    ${opts.checkpointTypeName}[] storage self,
+    ${opts.keyTypeName} key,
+    ${opts.valueTypeName} value
+) private returns (${opts.valueTypeName}, ${opts.valueTypeName}) {
+    uint256 pos = self.length;
+
+    if (pos > 0) {
+        // Copying to memory is important here.
+        ${opts.checkpointTypeName} memory last = _unsafeAccess(self, pos - 1);
+
+        // Checkpoint keys must be non-decreasing.
+        require(last.${opts.keyFieldName} <= key, "Checkpoint: decreasing keys");
+
+        // Update or push new checkpoint
+        if (last.${opts.keyFieldName} == key) {
+            _unsafeAccess(self, pos - 1).${opts.valueFieldName} = value;
+        } else {
+            self.push(${opts.checkpointTypeName}({${opts.keyFieldName}: key, ${opts.valueFieldName}: value}));
+        }
+        return (last.${opts.valueFieldName}, value);
+    } else {
+        self.push(${opts.checkpointTypeName}({${opts.keyFieldName}: key, ${opts.valueFieldName}: value}));
+        return (0, value);
+    }
+}
+
+/**
+ * @dev Return the index of the last (most recent) checkpoint with key lower or equal than the search key, or \`high\` if there is none.
+ * \`low\` and \`high\` define a section where to do the search, with inclusive \`low\` and exclusive \`high\`.
+ *
+ * WARNING: \`high\` should not be greater than the array's length.
+ */
+function _upperBinaryLookup(
+    ${opts.checkpointTypeName}[] storage self,
+    ${opts.keyTypeName} key,
+    uint256 low,
+    uint256 high
+) private view returns (uint256) {
+    while (low < high) {
+        uint256 mid = Math.average(low, high);
+        if (_unsafeAccess(self, mid).${opts.keyFieldName} > key) {
+            high = mid;
+        } else {
+            low = mid + 1;
+        }
+    }
+    return high;
+}
+
+/**
+ * @dev Return the index of the first (oldest) checkpoint with key is greater or equal than the search key, or \`high\` if there is none.
+ * \`low\` and \`high\` define a section where to do the search, with inclusive \`low\` and exclusive \`high\`.
+ *
+ * WARNING: \`high\` should not be greater than the array's length.
+ */
+function _lowerBinaryLookup(
+    ${opts.checkpointTypeName}[] storage self,
+    ${opts.keyTypeName} key,
+    uint256 low,
+    uint256 high
+) private view returns (uint256) {
+    while (low < high) {
+        uint256 mid = Math.average(low, high);
+        if (_unsafeAccess(self, mid).${opts.keyFieldName} < key) {
+            low = mid + 1;
+        } else {
+            high = mid;
+        }
+    }
+    return high;
+}
+
+/**
+ * @dev Access an element of the array without performing bounds check. The position is assumed to be within bounds.
+ */
+function _unsafeAccess(${opts.checkpointTypeName}[] storage self, uint256 pos)
+    private
+    pure
+    returns (${opts.checkpointTypeName} storage result)
+{
+    assembly {
+        mstore(0, self.slot)
+        result.slot := add(keccak256(0, 0x20), pos)
+    }
+}
+`;
+/* eslint-enable max-len */
+
+// GENERATE
+module.exports = format(
+  header.trimEnd(),
+  'library Checkpoints {',
+  [
+    // Legacy types & functions
+    types(LEGACY_OPTS),
+    legacyOperations(LEGACY_OPTS),
+    common(LEGACY_OPTS),
+    // New flavors
+    ...OPTS.flatMap(opts => [types(opts), operations(opts), common(opts)]),
+  ],
+  '}',
+);

backend/lib/openzeppelin-contracts/scripts/generate/templates/Checkpoints.opts.js

@@ -0,0 +1,22 @@
+// OPTIONS
+const VALUE_SIZES = [224, 160];
+
+const defaultOpts = size => ({
+  historyTypeName: `Trace${size}`,
+  checkpointTypeName: `Checkpoint${size}`,
+  checkpointFieldName: '_checkpoints',
+  keyTypeName: `uint${256 - size}`,
+  keyFieldName: '_key',
+  valueTypeName: `uint${size}`,
+  valueFieldName: '_value',
+});
+
+module.exports = {
+  OPTS: VALUE_SIZES.map(size => defaultOpts(size)),
+  LEGACY_OPTS: {
+    ...defaultOpts(224),
+    historyTypeName: 'History',
+    checkpointTypeName: 'Checkpoint',
+    keyFieldName: '_blockNumber',
+  },
+};

backend/lib/openzeppelin-contracts/scripts/generate/templates/Checkpoints.t.js

@@ -0,0 +1,256 @@
+const format = require('../format-lines');
+const { capitalize } = require('../../helpers');
+const { OPTS, LEGACY_OPTS } = require('./Checkpoints.opts.js');
+
+// TEMPLATE
+const header = `\
+pragma solidity ^0.8.0;
+
+import "forge-std/Test.sol";
+import "../../contracts/utils/Checkpoints.sol";
+import "../../contracts/utils/math/SafeCast.sol";
+`;
+
+/* eslint-disable max-len */
+const common = opts => `\
+using Checkpoints for Checkpoints.${opts.historyTypeName};
+
+// Maximum gap between keys used during the fuzzing tests: the \`_prepareKeys\` function with make sure that
+// key#n+1 is in the [key#n, key#n + _KEY_MAX_GAP] range.
+uint8 internal constant _KEY_MAX_GAP = 64;
+
+Checkpoints.${opts.historyTypeName} internal _ckpts;
+
+// helpers
+function _bound${capitalize(opts.keyTypeName)}(
+    ${opts.keyTypeName} x,
+    ${opts.keyTypeName} min,
+    ${opts.keyTypeName} max
+) internal view returns (${opts.keyTypeName}) {
+    return SafeCast.to${capitalize(opts.keyTypeName)}(bound(uint256(x), uint256(min), uint256(max)));
+}
+
+function _prepareKeys(
+    ${opts.keyTypeName}[] memory keys,
+    ${opts.keyTypeName} maxSpread
+) internal view {
+    ${opts.keyTypeName} lastKey = 0;
+    for (uint256 i = 0; i < keys.length; ++i) {
+        ${opts.keyTypeName} key = _bound${capitalize(opts.keyTypeName)}(keys[i], lastKey, lastKey + maxSpread);
+        keys[i] = key;
+        lastKey = key;
+    }
+}
+
+function _assertLatestCheckpoint(
+    bool exist,
+    ${opts.keyTypeName} key,
+    ${opts.valueTypeName} value
+) internal {
+    (bool _exist, ${opts.keyTypeName} _key, ${opts.valueTypeName} _value) = _ckpts.latestCheckpoint();
+    assertEq(_exist, exist);
+    assertEq(_key, key);
+    assertEq(_value, value);
+}
+`;
+
+const testTrace = opts => `\
+// tests
+function testPush(
+    ${opts.keyTypeName}[] memory keys,
+    ${opts.valueTypeName}[] memory values,
+    ${opts.keyTypeName} pastKey
+) public {
+    vm.assume(values.length > 0 && values.length <= keys.length);
+    _prepareKeys(keys, _KEY_MAX_GAP);
+
+    // initial state
+    assertEq(_ckpts.length(), 0);
+    assertEq(_ckpts.latest(), 0);
+    _assertLatestCheckpoint(false, 0, 0);
+
+    uint256 duplicates = 0;
+    for (uint256 i = 0; i < keys.length; ++i) {
+        ${opts.keyTypeName} key = keys[i];
+        ${opts.valueTypeName} value = values[i % values.length];
+        if (i > 0 && key == keys[i-1]) ++duplicates;
+
+        // push
+        _ckpts.push(key, value);
+
+        // check length & latest
+        assertEq(_ckpts.length(), i + 1 - duplicates);
+        assertEq(_ckpts.latest(), value);
+        _assertLatestCheckpoint(true, key, value);
+    }
+
+    if (keys.length > 0) {
+        ${opts.keyTypeName} lastKey = keys[keys.length - 1];
+        if (lastKey > 0) {
+            pastKey = _bound${capitalize(opts.keyTypeName)}(pastKey, 0, lastKey - 1);
+    
+            vm.expectRevert();
+            this.push(pastKey, values[keys.length % values.length]);
+        }
+    }
+}
+
+// used to test reverts
+function push(${opts.keyTypeName} key, ${opts.valueTypeName} value) external {
+  _ckpts.push(key, value);
+}
+
+function testLookup(
+    ${opts.keyTypeName}[] memory keys,
+    ${opts.valueTypeName}[] memory values,
+    ${opts.keyTypeName} lookup
+) public {
+    vm.assume(values.length > 0 && values.length <= keys.length);
+    _prepareKeys(keys, _KEY_MAX_GAP);
+
+    ${opts.keyTypeName} lastKey = keys.length == 0 ? 0 : keys[keys.length - 1];
+    lookup = _bound${capitalize(opts.keyTypeName)}(lookup, 0, lastKey + _KEY_MAX_GAP);
+
+    ${opts.valueTypeName} upper = 0;
+    ${opts.valueTypeName} lower = 0;
+    ${opts.keyTypeName} lowerKey = type(${opts.keyTypeName}).max;
+    for (uint256 i = 0; i < keys.length; ++i) {
+        ${opts.keyTypeName} key = keys[i];
+        ${opts.valueTypeName} value = values[i % values.length];
+
+        // push
+        _ckpts.push(key, value);
+
+        // track expected result of lookups
+        if (key <= lookup) {
+            upper = value;
+        }
+        // find the first key that is not smaller than the lookup key
+        if (key >= lookup && (i == 0 || keys[i-1] < lookup)) {
+            lowerKey = key;
+        }
+        if (key == lowerKey) {
+            lower = value;
+        }
+    }
+
+    // check lookup
+    assertEq(_ckpts.lowerLookup(lookup), lower);
+    assertEq(_ckpts.upperLookup(lookup), upper);
+    assertEq(_ckpts.upperLookupRecent(lookup), upper);
+}
+`;
+
+const testHistory = opts => `\
+// tests
+function testPush(
+    ${opts.keyTypeName}[] memory keys,
+    ${opts.valueTypeName}[] memory values,
+    ${opts.keyTypeName} pastKey
+) public {
+    vm.assume(values.length > 0 && values.length <= keys.length);
+    _prepareKeys(keys, _KEY_MAX_GAP);
+
+    // initial state
+    assertEq(_ckpts.length(), 0);
+    assertEq(_ckpts.latest(), 0);
+    _assertLatestCheckpoint(false, 0, 0);
+
+    uint256 duplicates = 0;
+    for (uint256 i = 0; i < keys.length; ++i) {
+        ${opts.keyTypeName} key = keys[i];
+        ${opts.valueTypeName} value = values[i % values.length];
+        if (i > 0 && key == keys[i - 1]) ++duplicates;
+
+        // push
+        vm.roll(key);
+        _ckpts.push(value);
+
+        // check length & latest
+        assertEq(_ckpts.length(), i + 1 - duplicates);
+        assertEq(_ckpts.latest(), value);
+        _assertLatestCheckpoint(true, key, value);
+    }
+
+    // Can't push any key in the past
+    if (keys.length > 0) {
+        ${opts.keyTypeName} lastKey = keys[keys.length - 1];
+        if (lastKey > 0) {
+            pastKey = _bound${capitalize(opts.keyTypeName)}(pastKey, 0, lastKey - 1);
+    
+            vm.roll(pastKey);
+            vm.expectRevert();
+            this.push(values[keys.length % values.length]);
+        }
+    }
+}
+
+// used to test reverts
+function push(${opts.valueTypeName} value) external {
+  _ckpts.push(value);
+}
+
+function testLookup(
+    ${opts.keyTypeName}[] memory keys,
+    ${opts.valueTypeName}[] memory values,
+    ${opts.keyTypeName} lookup
+) public {
+    vm.assume(keys.length > 0);
+    vm.assume(values.length > 0 && values.length <= keys.length);
+    _prepareKeys(keys, _KEY_MAX_GAP);
+
+    ${opts.keyTypeName} lastKey = keys[keys.length - 1];
+    vm.assume(lastKey > 0);
+    lookup = _bound${capitalize(opts.keyTypeName)}(lookup, 0, lastKey - 1);
+
+    ${opts.valueTypeName} upper = 0;
+    for (uint256 i = 0; i < keys.length; ++i) {
+        ${opts.keyTypeName} key = keys[i];
+        ${opts.valueTypeName} value = values[i % values.length];
+
+        // push
+        vm.roll(key);
+        _ckpts.push(value);
+
+        // track expected result of lookups
+        if (key <= lookup) {
+            upper = value;
+        }
+    }
+
+    // check lookup
+    assertEq(_ckpts.getAtBlock(lookup), upper);
+    assertEq(_ckpts.getAtProbablyRecentBlock(lookup), upper);
+
+    vm.expectRevert(); this.getAtBlock(lastKey);
+    vm.expectRevert(); this.getAtBlock(lastKey + 1);
+    vm.expectRevert(); this.getAtProbablyRecentBlock(lastKey);
+    vm.expectRevert(); this.getAtProbablyRecentBlock(lastKey + 1);
+}
+
+// used to test reverts
+function getAtBlock(${opts.keyTypeName} key) external view {
+  _ckpts.getAtBlock(key);
+}
+
+// used to test reverts
+function getAtProbablyRecentBlock(${opts.keyTypeName} key) external view {
+  _ckpts.getAtProbablyRecentBlock(key);
+}
+`;
+/* eslint-enable max-len */
+
+// GENERATE
+module.exports = format(
+  header,
+  // HISTORY
+  `contract Checkpoints${LEGACY_OPTS.historyTypeName}Test is Test {`,
+  [common(LEGACY_OPTS), testHistory(LEGACY_OPTS)],
+  '}',
+  // TRACEXXX
+  ...OPTS.flatMap(opts => [
+    `contract Checkpoints${opts.historyTypeName}Test is Test {`,
+    [common(opts), testTrace(opts)],
+    '}',
+  ]),
+);

backend/lib/openzeppelin-contracts/scripts/generate/templates/EnumerableMap.js

@@ -0,0 +1,310 @@
+const format = require('../format-lines');
+const { fromBytes32, toBytes32 } = require('./conversion');
+
+const TYPES = [
+  { name: 'UintToUintMap', keyType: 'uint256', valueType: 'uint256' },
+  { name: 'UintToAddressMap', keyType: 'uint256', valueType: 'address' },
+  { name: 'AddressToUintMap', keyType: 'address', valueType: 'uint256' },
+  { name: 'Bytes32ToUintMap', keyType: 'bytes32', valueType: 'uint256' },
+];
+
+/* eslint-disable max-len */
+const header = `\
+pragma solidity ^0.8.0;
+
+import "./EnumerableSet.sol";
+
+/**
+ * @dev Library for managing an enumerable variant of Solidity's
+ * https://solidity.readthedocs.io/en/latest/types.html#mapping-types[\`mapping\`]
+ * type.
+ *
+ * Maps have the following properties:
+ *
+ * - Entries are added, removed, and checked for existence in constant time
+ * (O(1)).
+ * - Entries are enumerated in O(n). No guarantees are made on the ordering.
+ *
+ * \`\`\`solidity
+ * contract Example {
+ *     // Add the library methods
+ *     using EnumerableMap for EnumerableMap.UintToAddressMap;
+ *
+ *     // Declare a set state variable
+ *     EnumerableMap.UintToAddressMap private myMap;
+ * }
+ * \`\`\`
+ *
+ * The following map types are supported:
+ *
+ * - \`uint256 -> address\` (\`UintToAddressMap\`) since v3.0.0
+ * - \`address -> uint256\` (\`AddressToUintMap\`) since v4.6.0
+ * - \`bytes32 -> bytes32\` (\`Bytes32ToBytes32Map\`) since v4.6.0
+ * - \`uint256 -> uint256\` (\`UintToUintMap\`) since v4.7.0
+ * - \`bytes32 -> uint256\` (\`Bytes32ToUintMap\`) since v4.7.0
+ *
+ * [WARNING]
+ * ====
+ * Trying to delete such a structure from storage will likely result in data corruption, rendering the structure
+ * unusable.
+ * See https://github.com/ethereum/solidity/pull/11843[ethereum/solidity#11843] for more info.
+ *
+ * In order to clean an EnumerableMap, you can either remove all elements one by one or create a fresh instance using an
+ * array of EnumerableMap.
+ * ====
+ */
+`;
+/* eslint-enable max-len */
+
+const defaultMap = () => `\
+// To implement this library for multiple types with as little code
+// repetition as possible, we write it in terms of a generic Map type with
+// bytes32 keys and values.
+// The Map implementation uses private functions, and user-facing
+// implementations (such as Uint256ToAddressMap) are just wrappers around
+// the underlying Map.
+// This means that we can only create new EnumerableMaps for types that fit
+// in bytes32.
+
+struct Bytes32ToBytes32Map {
+    // Storage of keys
+    EnumerableSet.Bytes32Set _keys;
+    mapping(bytes32 => bytes32) _values;
+}
+
+/**
+ * @dev Adds a key-value pair to a map, or updates the value for an existing
+ * key. O(1).
+ *
+ * Returns true if the key was added to the map, that is if it was not
+ * already present.
+ */
+function set(
+    Bytes32ToBytes32Map storage map,
+    bytes32 key,
+    bytes32 value
+) internal returns (bool) {
+    map._values[key] = value;
+    return map._keys.add(key);
+}
+
+/**
+ * @dev Removes a key-value pair from a map. O(1).
+ *
+ * Returns true if the key was removed from the map, that is if it was present.
+ */
+function remove(Bytes32ToBytes32Map storage map, bytes32 key) internal returns (bool) {
+    delete map._values[key];
+    return map._keys.remove(key);
+}
+
+/**
+ * @dev Returns true if the key is in the map. O(1).
+ */
+function contains(Bytes32ToBytes32Map storage map, bytes32 key) internal view returns (bool) {
+    return map._keys.contains(key);
+}
+
+/**
+ * @dev Returns the number of key-value pairs in the map. O(1).
+ */
+function length(Bytes32ToBytes32Map storage map) internal view returns (uint256) {
+    return map._keys.length();
+}
+
+/**
+ * @dev Returns the key-value pair stored at position \`index\` in the map. O(1).
+ *
+ * Note that there are no guarantees on the ordering of entries inside the
+ * array, and it may change when more entries are added or removed.
+ *
+ * Requirements:
+ *
+ * - \`index\` must be strictly less than {length}.
+ */
+function at(Bytes32ToBytes32Map storage map, uint256 index) internal view returns (bytes32, bytes32) {
+    bytes32 key = map._keys.at(index);
+    return (key, map._values[key]);
+}
+
+/**
+ * @dev Tries to returns the value associated with \`key\`. O(1).
+ * Does not revert if \`key\` is not in the map.
+ */
+function tryGet(Bytes32ToBytes32Map storage map, bytes32 key) internal view returns (bool, bytes32) {
+    bytes32 value = map._values[key];
+    if (value == bytes32(0)) {
+        return (contains(map, key), bytes32(0));
+    } else {
+        return (true, value);
+    }
+}
+
+/**
+ * @dev Returns the value associated with \`key\`. O(1).
+ *
+ * Requirements:
+ *
+ * - \`key\` must be in the map.
+ */
+function get(Bytes32ToBytes32Map storage map, bytes32 key) internal view returns (bytes32) {
+    bytes32 value = map._values[key];
+    require(value != 0 || contains(map, key), "EnumerableMap: nonexistent key");
+    return value;
+}
+
+/**
+ * @dev Same as {get}, with a custom error message when \`key\` is not in the map.
+ *
+ * CAUTION: This function is deprecated because it requires allocating memory for the error
+ * message unnecessarily. For custom revert reasons use {tryGet}.
+ */
+function get(
+    Bytes32ToBytes32Map storage map,
+    bytes32 key,
+    string memory errorMessage
+) internal view returns (bytes32) {
+    bytes32 value = map._values[key];
+    require(value != 0 || contains(map, key), errorMessage);
+    return value;
+}
+
+/**
+ * @dev Return the an array containing all the keys
+ *
+ * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
+ * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
+ * this function has an unbounded cost, and using it as part of a state-changing function may render the function
+ * uncallable if the map grows to a point where copying to memory consumes too much gas to fit in a block.
+ */
+function keys(Bytes32ToBytes32Map storage map) internal view returns (bytes32[] memory) {
+    return map._keys.values();
+}
+`;
+
+const customMap = ({ name, keyType, valueType }) => `\
+// ${name}
+
+struct ${name} {
+    Bytes32ToBytes32Map _inner;
+}
+
+/**
+ * @dev Adds a key-value pair to a map, or updates the value for an existing
+ * key. O(1).
+ *
+ * Returns true if the key was added to the map, that is if it was not
+ * already present.
+ */
+function set(
+    ${name} storage map,
+    ${keyType} key,
+    ${valueType} value
+) internal returns (bool) {
+    return set(map._inner, ${toBytes32(keyType, 'key')}, ${toBytes32(valueType, 'value')});
+}
+
+/**
+ * @dev Removes a value from a map. O(1).
+ *
+ * Returns true if the key was removed from the map, that is if it was present.
+ */
+function remove(${name} storage map, ${keyType} key) internal returns (bool) {
+    return remove(map._inner, ${toBytes32(keyType, 'key')});
+}
+
+/**
+ * @dev Returns true if the key is in the map. O(1).
+ */
+function contains(${name} storage map, ${keyType} key) internal view returns (bool) {
+    return contains(map._inner, ${toBytes32(keyType, 'key')});
+}
+
+/**
+ * @dev Returns the number of elements in the map. O(1).
+ */
+function length(${name} storage map) internal view returns (uint256) {
+    return length(map._inner);
+}
+
+/**
+ * @dev Returns the element stored at position \`index\` in the map. O(1).
+ * Note that there are no guarantees on the ordering of values inside the
+ * array, and it may change when more values are added or removed.
+ *
+ * Requirements:
+ *
+ * - \`index\` must be strictly less than {length}.
+ */
+function at(${name} storage map, uint256 index) internal view returns (${keyType}, ${valueType}) {
+    (bytes32 key, bytes32 value) = at(map._inner, index);
+    return (${fromBytes32(keyType, 'key')}, ${fromBytes32(valueType, 'value')});
+}
+
+/**
+ * @dev Tries to returns the value associated with \`key\`. O(1).
+ * Does not revert if \`key\` is not in the map.
+ */
+function tryGet(${name} storage map, ${keyType} key) internal view returns (bool, ${valueType}) {
+    (bool success, bytes32 value) = tryGet(map._inner, ${toBytes32(keyType, 'key')});
+    return (success, ${fromBytes32(valueType, 'value')});
+}
+
+/**
+ * @dev Returns the value associated with \`key\`. O(1).
+ *
+ * Requirements:
+ *
+ * - \`key\` must be in the map.
+ */
+function get(${name} storage map, ${keyType} key) internal view returns (${valueType}) {
+    return ${fromBytes32(valueType, `get(map._inner, ${toBytes32(keyType, 'key')})`)};
+}
+
+/**
+ * @dev Same as {get}, with a custom error message when \`key\` is not in the map.
+ *
+ * CAUTION: This function is deprecated because it requires allocating memory for the error
+ * message unnecessarily. For custom revert reasons use {tryGet}.
+ */
+function get(
+    ${name} storage map,
+    ${keyType} key,
+    string memory errorMessage
+) internal view returns (${valueType}) {
+    return ${fromBytes32(valueType, `get(map._inner, ${toBytes32(keyType, 'key')}, errorMessage)`)};
+}
+
+/**
+ * @dev Return the an array containing all the keys
+ *
+ * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
+ * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
+ * this function has an unbounded cost, and using it as part of a state-changing function may render the function
+ * uncallable if the map grows to a point where copying to memory consumes too much gas to fit in a block.
+ */
+function keys(${name} storage map) internal view returns (${keyType}[] memory) {
+    bytes32[] memory store = keys(map._inner);
+    ${keyType}[] memory result;
+
+    /// @solidity memory-safe-assembly
+    assembly {
+        result := store
+    }
+
+    return result;
+}
+`;
+
+// GENERATE
+module.exports = format(
+  header.trimEnd(),
+  'library EnumerableMap {',
+  [
+    'using EnumerableSet for EnumerableSet.Bytes32Set;',
+    '',
+    defaultMap(),
+    TYPES.map(details => customMap(details).trimEnd()).join('\n\n'),
+  ],
+  '}',
+);

backend/lib/openzeppelin-contracts/scripts/generate/templates/EnumerableSet.js

@@ -0,0 +1,250 @@
+const format = require('../format-lines');
+const { fromBytes32, toBytes32 } = require('./conversion');
+
+const TYPES = [
+  { name: 'Bytes32Set', type: 'bytes32' },
+  { name: 'AddressSet', type: 'address' },
+  { name: 'UintSet', type: 'uint256' },
+];
+
+/* eslint-disable max-len */
+const header = `\
+pragma solidity ^0.8.0;
+
+/**
+ * @dev Library for managing
+ * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
+ * types.
+ *
+ * Sets have the following properties:
+ *
+ * - Elements are added, removed, and checked for existence in constant time
+ * (O(1)).
+ * - Elements are enumerated in O(n). No guarantees are made on the ordering.
+ *
+ * \`\`\`solidity
+ * contract Example {
+ *     // Add the library methods
+ *     using EnumerableSet for EnumerableSet.AddressSet;
+ *
+ *     // Declare a set state variable
+ *     EnumerableSet.AddressSet private mySet;
+ * }
+ * \`\`\`
+ *
+ * As of v3.3.0, sets of type \`bytes32\` (\`Bytes32Set\`), \`address\` (\`AddressSet\`)
+ * and \`uint256\` (\`UintSet\`) are supported.
+ *
+ * [WARNING]
+ * ====
+ * Trying to delete such a structure from storage will likely result in data corruption, rendering the structure
+ * unusable.
+ * See https://github.com/ethereum/solidity/pull/11843[ethereum/solidity#11843] for more info.
+ *
+ * In order to clean an EnumerableSet, you can either remove all elements one by one or create a fresh instance using an
+ * array of EnumerableSet.
+ * ====
+ */
+`;
+/* eslint-enable max-len */
+
+const defaultSet = () => `\
+// To implement this library for multiple types with as little code
+// repetition as possible, we write it in terms of a generic Set type with
+// bytes32 values.
+// The Set implementation uses private functions, and user-facing
+// implementations (such as AddressSet) are just wrappers around the
+// underlying Set.
+// This means that we can only create new EnumerableSets for types that fit
+// in bytes32.
+
+struct Set {
+    // Storage of set values
+    bytes32[] _values;
+    // Position of the value in the \`values\` array, plus 1 because index 0
+    // means a value is not in the set.
+    mapping(bytes32 => uint256) _indexes;
+}
+
+/**
+ * @dev Add a value to a set. O(1).
+ *
+ * Returns true if the value was added to the set, that is if it was not
+ * already present.
+ */
+function _add(Set storage set, bytes32 value) private returns (bool) {
+    if (!_contains(set, value)) {
+        set._values.push(value);
+        // The value is stored at length-1, but we add 1 to all indexes
+        // and use 0 as a sentinel value
+        set._indexes[value] = set._values.length;
+        return true;
+    } else {
+        return false;
+    }
+}
+
+/**
+ * @dev Removes a value from a set. O(1).
+ *
+ * Returns true if the value was removed from the set, that is if it was
+ * present.
+ */
+function _remove(Set storage set, bytes32 value) private returns (bool) {
+    // We read and store the value's index to prevent multiple reads from the same storage slot
+    uint256 valueIndex = set._indexes[value];
+
+    if (valueIndex != 0) {
+        // Equivalent to contains(set, value)
+        // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
+        // the array, and then remove the last element (sometimes called as 'swap and pop').
+        // This modifies the order of the array, as noted in {at}.
+
+        uint256 toDeleteIndex = valueIndex - 1;
+        uint256 lastIndex = set._values.length - 1;
+
+        if (lastIndex != toDeleteIndex) {
+            bytes32 lastValue = set._values[lastIndex];
+
+            // Move the last value to the index where the value to delete is
+            set._values[toDeleteIndex] = lastValue;
+            // Update the index for the moved value
+            set._indexes[lastValue] = valueIndex; // Replace lastValue's index to valueIndex
+        }
+
+        // Delete the slot where the moved value was stored
+        set._values.pop();
+
+        // Delete the index for the deleted slot
+        delete set._indexes[value];
+
+        return true;
+    } else {
+        return false;
+    }
+}
+
+/**
+ * @dev Returns true if the value is in the set. O(1).
+ */
+function _contains(Set storage set, bytes32 value) private view returns (bool) {
+    return set._indexes[value] != 0;
+}
+
+/**
+ * @dev Returns the number of values on the set. O(1).
+ */
+function _length(Set storage set) private view returns (uint256) {
+    return set._values.length;
+}
+
+/**
+ * @dev Returns the value stored at position \`index\` in the set. O(1).
+ *
+ * Note that there are no guarantees on the ordering of values inside the
+ * array, and it may change when more values are added or removed.
+ *
+ * Requirements:
+ *
+ * - \`index\` must be strictly less than {length}.
+ */
+function _at(Set storage set, uint256 index) private view returns (bytes32) {
+    return set._values[index];
+}
+
+/**
+ * @dev Return the entire set in an array
+ *
+ * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
+ * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
+ * this function has an unbounded cost, and using it as part of a state-changing function may render the function
+ * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
+ */
+function _values(Set storage set) private view returns (bytes32[] memory) {
+    return set._values;
+}
+`;
+
+const customSet = ({ name, type }) => `\
+// ${name}
+
+struct ${name} {
+    Set _inner;
+}
+
+/**
+ * @dev Add a value to a set. O(1).
+ *
+ * Returns true if the value was added to the set, that is if it was not
+ * already present.
+ */
+function add(${name} storage set, ${type} value) internal returns (bool) {
+    return _add(set._inner, ${toBytes32(type, 'value')});
+}
+
+/**
+ * @dev Removes a value from a set. O(1).
+ *
+ * Returns true if the value was removed from the set, that is if it was
+ * present.
+ */
+function remove(${name} storage set, ${type} value) internal returns (bool) {
+    return _remove(set._inner, ${toBytes32(type, 'value')});
+}
+
+/**
+ * @dev Returns true if the value is in the set. O(1).
+ */
+function contains(${name} storage set, ${type} value) internal view returns (bool) {
+    return _contains(set._inner, ${toBytes32(type, 'value')});
+}
+
+/**
+ * @dev Returns the number of values in the set. O(1).
+ */
+function length(${name} storage set) internal view returns (uint256) {
+    return _length(set._inner);
+}
+
+/**
+ * @dev Returns the value stored at position \`index\` in the set. O(1).
+ *
+ * Note that there are no guarantees on the ordering of values inside the
+ * array, and it may change when more values are added or removed.
+ *
+ * Requirements:
+ *
+ * - \`index\` must be strictly less than {length}.
+ */
+function at(${name} storage set, uint256 index) internal view returns (${type}) {
+    return ${fromBytes32(type, '_at(set._inner, index)')};
+}
+
+/**
+ * @dev Return the entire set in an array
+ *
+ * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
+ * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
+ * this function has an unbounded cost, and using it as part of a state-changing function may render the function
+ * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
+ */
+function values(${name} storage set) internal view returns (${type}[] memory) {
+    bytes32[] memory store = _values(set._inner);
+    ${type}[] memory result;
+
+    /// @solidity memory-safe-assembly
+    assembly {
+        result := store
+    }
+
+    return result;
+}
+`;
+
+// GENERATE
+module.exports = format(
+  header.trimEnd(),
+  'library EnumerableSet {',
+  [defaultSet(), TYPES.map(details => customSet(details).trimEnd()).join('\n\n')],
+  '}',
+);

backend/lib/openzeppelin-contracts/scripts/generate/templates/SafeCast.js

@@ -0,0 +1,163 @@
+const assert = require('assert');
+const format = require('../format-lines');
+const { range } = require('../../helpers');
+
+const LENGTHS = range(8, 256, 8).reverse(); // 248 → 8 (in steps of 8)
+
+// Returns the version of OpenZeppelin Contracts in which a particular function was introduced.
+// This is used in the docs for each function.
+const version = (selector, length) => {
+  switch (selector) {
+    case 'toUint(uint)': {
+      switch (length) {
+        case 8:
+        case 16:
+        case 32:
+        case 64:
+        case 128:
+          return '2.5';
+        case 96:
+        case 224:
+          return '4.2';
+        default:
+          assert(LENGTHS.includes(length));
+          return '4.7';
+      }
+    }
+    case 'toInt(int)': {
+      switch (length) {
+        case 8:
+        case 16:
+        case 32:
+        case 64:
+        case 128:
+          return '3.1';
+        default:
+          assert(LENGTHS.includes(length));
+          return '4.7';
+      }
+    }
+    case 'toUint(int)': {
+      switch (length) {
+        case 256:
+          return '3.0';
+        default:
+          assert(false);
+          return;
+      }
+    }
+    case 'toInt(uint)': {
+      switch (length) {
+        case 256:
+          return '3.0';
+        default:
+          assert(false);
+          return;
+      }
+    }
+    default:
+      assert(false);
+  }
+};
+
+const header = `\
+pragma solidity ^0.8.0;
+
+/**
+ * @dev Wrappers over Solidity's uintXX/intXX casting operators with added overflow
+ * checks.
+ *
+ * Downcasting from uint256/int256 in Solidity does not revert on overflow. This can
+ * easily result in undesired exploitation or bugs, since developers usually
+ * assume that overflows raise errors. \`SafeCast\` restores this intuition by
+ * reverting the transaction when such an operation overflows.
+ *
+ * Using this library instead of the unchecked operations eliminates an entire
+ * class of bugs, so it's recommended to use it always.
+ *
+ * Can be combined with {SafeMath} and {SignedSafeMath} to extend it to smaller types, by performing
+ * all math on \`uint256\` and \`int256\` and then downcasting.
+ */
+`;
+
+const toUintDownCast = length => `\
+/**
+ * @dev Returns the downcasted uint${length} from uint256, reverting on
+ * overflow (when the input is greater than largest uint${length}).
+ *
+ * Counterpart to Solidity's \`uint${length}\` operator.
+ *
+ * Requirements:
+ *
+ * - input must fit into ${length} bits
+ *
+ * _Available since v${version('toUint(uint)', length)}._
+ */
+function toUint${length}(uint256 value) internal pure returns (uint${length}) {
+    require(value <= type(uint${length}).max, "SafeCast: value doesn't fit in ${length} bits");
+    return uint${length}(value);
+}
+`;
+
+/* eslint-disable max-len */
+const toIntDownCast = length => `\
+/**
+ * @dev Returns the downcasted int${length} from int256, reverting on
+ * overflow (when the input is less than smallest int${length} or
+ * greater than largest int${length}).
+ *
+ * Counterpart to Solidity's \`int${length}\` operator.
+ *
+ * Requirements:
+ *
+ * - input must fit into ${length} bits
+ *
+ * _Available since v${version('toInt(int)', length)}._
+ */
+function toInt${length}(int256 value) internal pure returns (int${length} downcasted) {
+    downcasted = int${length}(value);
+    require(downcasted == value, "SafeCast: value doesn't fit in ${length} bits");
+}
+`;
+/* eslint-enable max-len */
+
+const toInt = length => `\
+/**
+ * @dev Converts an unsigned uint${length} into a signed int${length}.
+ *
+ * Requirements:
+ *
+ * - input must be less than or equal to maxInt${length}.
+ *
+ * _Available since v${version('toInt(uint)', length)}._
+ */
+function toInt${length}(uint${length} value) internal pure returns (int${length}) {
+    // Note: Unsafe cast below is okay because \`type(int${length}).max\` is guaranteed to be positive
+    require(value <= uint${length}(type(int${length}).max), "SafeCast: value doesn't fit in an int${length}");
+    return int${length}(value);
+}
+`;
+
+const toUint = length => `\
+/**
+ * @dev Converts a signed int${length} into an unsigned uint${length}.
+ *
+ * Requirements:
+ *
+ * - input must be greater than or equal to 0.
+ *
+ * _Available since v${version('toUint(int)', length)}._
+ */
+function toUint${length}(int${length} value) internal pure returns (uint${length}) {
+    require(value >= 0, "SafeCast: value must be positive");
+    return uint${length}(value);
+}
+`;
+
+// GENERATE
+module.exports = format(
+  header.trimEnd(),
+  'library SafeCast {',
+  [...LENGTHS.map(toUintDownCast), toUint(256), ...LENGTHS.map(toIntDownCast), toInt(256)],
+  '}',
+);

backend/lib/openzeppelin-contracts/scripts/generate/templates/StorageSlot.js

@@ -0,0 +1,87 @@
+const format = require('../format-lines');
+const { capitalize, unique } = require('../../helpers');
+
+const TYPES = [
+  { type: 'address', isValueType: true, version: '4.1' },
+  { type: 'bool', isValueType: true, name: 'Boolean', version: '4.1' },
+  { type: 'bytes32', isValueType: true, version: '4.1' },
+  { type: 'uint256', isValueType: true, version: '4.1' },
+  { type: 'string', isValueType: false, version: '4.9' },
+  { type: 'bytes', isValueType: false, version: '4.9' },
+].map(type => Object.assign(type, { struct: (type.name ?? capitalize(type.type)) + 'Slot' }));
+
+const VERSIONS = unique(TYPES.map(t => t.version)).map(
+  version =>
+    `_Available since v${version} for ${TYPES.filter(t => t.version == version)
+      .map(t => `\`${t.type}\``)
+      .join(', ')}._`,
+);
+
+const header = `\
+pragma solidity ^0.8.0;
+
+/**
+ * @dev Library for reading and writing primitive types to specific storage slots.
+ *
+ * Storage slots are often used to avoid storage conflict when dealing with upgradeable contracts.
+ * This library helps with reading and writing to such slots without the need for inline assembly.
+ *
+ * The functions in this library return Slot structs that contain a \`value\` member that can be used to read or write.
+ *
+ * Example usage to set ERC1967 implementation slot:
+ * \`\`\`solidity
+ * contract ERC1967 {
+ *     bytes32 internal constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
+ *
+ *     function _getImplementation() internal view returns (address) {
+ *         return StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value;
+ *     }
+ *
+ *     function _setImplementation(address newImplementation) internal {
+ *         require(Address.isContract(newImplementation), "ERC1967: new implementation is not a contract");
+ *         StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
+ *     }
+ * }
+ * \`\`\`
+ *
+${VERSIONS.map(s => ` * ${s}`).join('\n')}
+ */
+`;
+
+const struct = type => `\
+struct ${type.struct} {
+  ${type.type} value;
+}
+`;
+
+const get = type => `\
+/**
+ * @dev Returns an \`${type.struct}\` with member \`value\` located at \`slot\`.
+ */
+function get${type.struct}(bytes32 slot) internal pure returns (${type.struct} storage r) {
+  /// @solidity memory-safe-assembly
+  assembly {
+      r.slot := slot
+  }
+}
+`;
+
+const getStorage = type => `\
+/**
+ * @dev Returns an \`${type.struct}\` representation of the ${type.type} storage pointer \`store\`.
+ */
+function get${type.struct}(${type.type} storage store) internal pure returns (${type.struct} storage r) {
+  /// @solidity memory-safe-assembly
+  assembly {
+      r.slot := store.slot
+  }
+}
+`;
+
+// GENERATE
+module.exports = format(
+  header.trimEnd(),
+  'library StorageSlot {',
+  [...TYPES.map(struct), ...TYPES.flatMap(type => [get(type), type.isValueType ? '' : getStorage(type)])],
+  '}',
+);

backend/lib/openzeppelin-contracts/scripts/generate/templates/conversion.js

@@ -0,0 +1,30 @@
+function toBytes32(type, value) {
+  switch (type) {
+    case 'bytes32':
+      return value;
+    case 'uint256':
+      return `bytes32(${value})`;
+    case 'address':
+      return `bytes32(uint256(uint160(${value})))`;
+    default:
+      throw new Error(`Conversion from ${type} to bytes32 not supported`);
+  }
+}
+
+function fromBytes32(type, value) {
+  switch (type) {
+    case 'bytes32':
+      return value;
+    case 'uint256':
+      return `uint256(${value})`;
+    case 'address':
+      return `address(uint160(uint256(${value})))`;
+    default:
+      throw new Error(`Conversion from bytes32 to ${type} not supported`);
+  }
+}
+
+module.exports = {
+  toBytes32,
+  fromBytes32,
+};