core: Move emu_window and key_map into core

* Removes circular dependences (common should not depend on core)

src/core/frontend/key_map.h

@@ -0,0 +1,93 @@
+// Copyright 2014 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <array>
+#include <tuple>
+#include "core/hle/service/hid/hid.h"
+
+class EmuWindow;
+
+namespace KeyMap {
+
+/**
+ * Represents key mapping targets that are not real 3DS buttons.
+ * They will be handled by KeyMap and translated to 3DS input.
+ */
+enum class IndirectTarget {
+    CirclePadUp,
+    CirclePadDown,
+    CirclePadLeft,
+    CirclePadRight,
+    CirclePadModifier,
+};
+
+/**
+ * Represents a key mapping target. It can be a PadState that represents real 3DS buttons,
+ * or an IndirectTarget.
+ */
+struct KeyTarget {
+    bool direct;
+    union {
+        u32 direct_target_hex;
+        IndirectTarget indirect_target;
+    } target;
+
+    KeyTarget() : direct(true) {
+        target.direct_target_hex = 0;
+    }
+
+    KeyTarget(Service::HID::PadState pad) : direct(true) {
+        target.direct_target_hex = pad.hex;
+    }
+
+    KeyTarget(IndirectTarget i) : direct(false) {
+        target.indirect_target = i;
+    }
+};
+
+/**
+ * Represents a key for a specific host device.
+ */
+struct HostDeviceKey {
+    int key_code;
+    int device_id; ///< Uniquely identifies a host device
+
+    bool operator<(const HostDeviceKey& other) const {
+        return std::tie(key_code, device_id) < std::tie(other.key_code, other.device_id);
+    }
+
+    bool operator==(const HostDeviceKey& other) const {
+        return std::tie(key_code, device_id) == std::tie(other.key_code, other.device_id);
+    }
+};
+
+extern const std::array<KeyTarget, Settings::NativeInput::NUM_INPUTS> mapping_targets;
+
+/**
+ * Generates a new device id, which uniquely identifies a host device within KeyMap.
+ */
+int NewDeviceId();
+
+/**
+ * Maps a device-specific key to a target (a PadState or an IndirectTarget).
+ */
+void SetKeyMapping(HostDeviceKey key, KeyTarget target);
+
+/**
+ * Clears all key mappings belonging to one device.
+ */
+void ClearKeyMapping(int device_id);
+
+/**
+ * Maps a key press action and call the corresponding function in EmuWindow
+ */
+void PressKey(EmuWindow& emu_window, HostDeviceKey key);
+
+/**
+ * Maps a key release action and call the corresponding function in EmuWindow
+ */
+void ReleaseKey(EmuWindow& emu_window, HostDeviceKey key);
+}