htc: add htcfs server/service object skeletons

libraries/libstratosphere/source/htcfs/htcfs_cache_manager.hpp

@@ -0,0 +1,103 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#pragma once
+#include <stratosphere.hpp>
+
+namespace ams::htcfs {
+
+    class CacheManager {
+        private:
+            os::SdkMutex m_mutex;
+            void *m_cache;
+            size_t m_cache_size;
+            s64 m_cached_file_size;
+            size_t m_cached_data_size;
+            s32 m_cached_handle;
+            bool m_has_cached_handle;
+        public:
+            CacheManager(void *cache, size_t cache_size) : m_mutex(), m_cache(cache), m_cache_size(cache_size), m_cached_file_size(), m_cached_data_size(), m_cached_handle(), m_has_cached_handle() { /* ... */ }
+        public:
+            bool GetFileSize(s64 *out, s32 handle) {
+                /* Lock ourselves. */
+                std::scoped_lock lk(m_mutex);
+
+                /* Get the cached size, if we match. */
+                if (m_has_cached_handle && m_cached_handle == handle) {
+                    *out = m_cached_file_size;
+                    return true;
+                } else {
+                    return false;
+                }
+            }
+
+            void Invalidate() {
+                /* Lock ourselves. */
+                std::scoped_lock lk(m_mutex);
+
+                /* Note that we have no handle. */
+                m_has_cached_handle = false;
+            }
+
+            void Record(s64 file_size, const void *data, s32 handle, size_t data_size) {
+                /* Lock ourselves. */
+                std::scoped_lock lk(m_mutex);
+
+                /* Set our cached file size. */
+                m_cached_file_size = file_size;
+
+                /* Set our cached data size. */
+                m_cached_data_size = std::min(m_cache_size, data_size);
+
+                /* Copy the data. */
+                std::memcpy(m_cache, data, m_cached_data_size);
+
+                /* Set our cache handle. */
+                m_cached_handle = handle;
+
+                /* Note that we have cached data. */
+                m_has_cached_handle = true;
+            }
+
+            bool ReadFile(size_t *out, void *dst, s32 handle, size_t offset, size_t size) {
+                /* Lock ourselves. */
+                std::scoped_lock lk(m_mutex);
+
+                /* Check that we have a cached file. */
+                if (!m_has_cached_handle) {
+                    return false;
+                }
+
+                /* Check the file is our cached one. */
+                if (handle != m_cached_handle) {
+                    return false;
+                }
+
+                /* Check that we can read data. */
+                if (offset + size > m_cached_data_size) {
+                    return false;
+                }
+
+                /* Copy the cached data. */
+                std::memcpy(dst, static_cast<const u8 *>(m_cache) + offset, size);
+
+                /* Set the output read size. */
+                *out = size;
+
+                return true;
+            }
+    };
+
+}