LibWeb: Add a Key type for IndexedDB

Author: https://github.com/stelar7
Commit: 34479e5664
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/2279
Reviewed-by: https://github.com/gmta
Reviewed-by: https://github.com/tcl3

Libraries/LibWeb/IndexedDB/Internal/Key.cpp

@@ -0,0 +1,157 @@
+/*
+ * Copyright (c) 2024, stelar7 <dudedbz@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibWeb/IndexedDB/Internal/Key.h>
+#include <LibWeb/Infra/ByteSequences.h>
+#include <LibWeb/Infra/Strings.h>
+
+namespace Web::IndexedDB {
+
+// https://w3c.github.io/IndexedDB/#compare-two-keys
+i8 Key::compare_two_keys(Key a, Key b)
+{
+    // 1. Let ta be the type of a.
+    auto ta = a.type();
+
+    // 2. Let tb be the type of b.
+    auto tb = b.type();
+
+    // 3. If ta does not equal tb, then run these steps:
+    if (ta != tb) {
+        // 1. If ta is array, then return 1.
+        if (ta == KeyType::Array)
+            return 1;
+
+        // 1. If tb is array, then return -1.
+        if (tb == KeyType::Array)
+            return -1;
+
+        // 1. If ta is binary, then return 1.
+        if (ta == KeyType::Binary)
+            return 1;
+
+        // 1. If tb is binary, then return -1.
+        if (tb == KeyType::Binary)
+            return -1;
+
+        // 1. If ta is string, then return 1.
+        if (ta == KeyType::String)
+            return 1;
+
+        // 1. If tb is string, then return -1.
+        if (tb == KeyType::String)
+            return -1;
+
+        // 1. If ta is date, then return 1.
+        if (ta == KeyType::Date)
+            return 1;
+
+        // 1. Assert: tb is date.
+        VERIFY(tb == KeyType::Date);
+
+        // 1. Return -1.
+        return -1;
+    }
+
+    // 4. Let va be the value of a.
+    auto va = a.value();
+
+    // 5. Let vb be the value of b.
+    auto vb = b.value();
+
+    // 6. Switch on ta:
+    switch (ta) {
+    // number
+    // date
+    case KeyType::Number:
+    case KeyType::Date: {
+        auto a_value = va.get<double>();
+        auto b_value = vb.get<double>();
+
+        // 1. If va is greater than vb, then return 1.
+        if (a_value > b_value)
+            return 1;
+
+        // 2. If va is less than vb, then return -1.
+        if (a_value < b_value)
+            return -1;
+
+        // 3. Return 0.
+        return 0;
+    }
+    // string
+    case KeyType::String: {
+        auto a_value = va.get<AK::String>();
+        auto b_value = vb.get<AK::String>();
+
+        // 1. If va is code unit less than vb, then return -1.
+        if (Infra::code_unit_less_than(a_value, b_value))
+            return -1;
+
+        // 2. If vb is code unit less than va, then return 1.
+        if (Infra::code_unit_less_than(b_value, a_value))
+            return 1;
+
+        // 3. Return 0.
+        return 0;
+    }
+    // binary
+    case KeyType::Binary: {
+        auto a_value = va.get<ByteBuffer>();
+        auto b_value = vb.get<ByteBuffer>();
+
+        // 1. If va is byte less than vb, then return -1.
+        if (Infra::is_byte_less_than(a_value, b_value))
+            return -1;
+
+        // 2. If vb is byte less than va, then return 1.
+        if (Infra::is_byte_less_than(b_value, a_value))
+            return 1;
+
+        // 3. Return 0.
+        return 0;
+    }
+    // array
+    case KeyType::Array: {
+        auto a_value = va.get<Vector<Key>>();
+        auto b_value = vb.get<Vector<Key>>();
+
+        // 1. Let length be the lesser of va’s size and vb’s size.
+        auto length = min(a_value.size(), b_value.size());
+
+        // 2. Let i be 0.
+        u64 i = 0;
+
+        // 3. While i is less than length, then:
+        while (i < length) {
+            // 1. Let c be the result of recursively comparing two keys with va[i] and vb[i].
+            auto c = compare_two_keys(a_value[i], b_value[i]);
+
+            // 2. If c is not 0, return c.
+            if (c != 0)
+                return c;
+
+            // 3. Increase i by 1.
+            i++;
+        }
+
+        // 4. If va’s size is greater than vb’s size, then return 1.
+        if (a_value.size() > b_value.size())
+            return 1;
+
+        // 5. If va’s size is less than vb’s size, then return -1.
+        if (a_value.size() < b_value.size())
+            return -1;
+
+        // 6. Return 0.
+        return 0;
+    }
+    }
+
+    VERIFY_NOT_REACHED();
+}
+
+}