first try to simplify the architecture (remove redundant inode_file and open() methods), add ext2_file placeholder struct

14 files changed, 75 insertions, 123 deletions

diff --git a/kernel/CMakeLists.txt b/kernel/CMakeLists.txt
index a36eac0..a8287ba 100644
--- a/kernel/CMakeLists.txt
+++ b/kernel/CMakeLists.txt
@@ -21,6 +21,7 @@ add_executable("kernel"
     "src/devices/storage/storage_management.cpp"
     "src/devices/storage/ram_disk/ram_disk_controller.cpp"
     "src/devices/storage/ram_disk/ram_disk_device.cpp"
+    "src/filesystem/ext2/ext2_file.cpp"
     "src/filesystem/ext2/ext2_filesystem.cpp"
     "src/filesystem/ext2/ext2_inode.cpp"
     "src/filesystem/custody.cpp"
@@ -28,7 +29,6 @@ add_executable("kernel"
     "src/filesystem/device_inode.cpp"
     "src/filesystem/file_descriptor_table.cpp"
     "src/filesystem/filesystem.cpp"
-    "src/filesystem/inode_file.cpp"
     "src/filesystem/inode.cpp"
     "src/filesystem/mount.cpp"
     "src/filesystem/open_file_description.cpp"
diff --git a/kernel/include/kernel/filesystem/device_file.hpp b/kernel/include/kernel/filesystem/device_file.hpp
index 06aa9b2..ff803f8 100644
--- a/kernel/include/kernel/filesystem/device_file.hpp
+++ b/kernel/include/kernel/filesystem/device_file.hpp
@@ -15,8 +15,6 @@ namespace filesystem
   {
     explicit device_file(kstd::shared_ptr<devices::device> const & device);
 
-    auto open() -> void override;
-
     auto read(void * buffer, size_t offset, size_t size) const -> size_t override;
     auto write(void const * buffer, size_t offset, size_t size) -> size_t override;
 
diff --git a/kernel/include/kernel/filesystem/device_inode.hpp b/kernel/include/kernel/filesystem/device_inode.hpp
index 0287875..c38c75b 100644
--- a/kernel/include/kernel/filesystem/device_inode.hpp
+++ b/kernel/include/kernel/filesystem/device_inode.hpp
@@ -2,22 +2,18 @@
 #define TEACH_OS_KERNEL_FILESYSTEM_DEVICE_INODE_HPP
 
 #include "kernel/devices/device.hpp"
+#include "kernel/filesystem/file.hpp"
 #include "kernel/filesystem/inode.hpp"
 
 #include <kstd/memory>
 
-#include <cstddef>
-
 namespace filesystem
 {
   struct device_inode : inode
   {
     explicit device_inode(kstd::shared_ptr<devices::device> const & device);
 
-    [[nodiscard]] auto backing_device() const -> kstd::shared_ptr<devices::device> const &;
-
-    auto read(void * buffer, size_t offset, size_t size) const -> size_t override;
-    auto write(void const * buffer, size_t offset, size_t size) -> size_t override;
+    [[nodiscard]] auto open_file() const -> kstd::shared_ptr<file> override;
 
   private:
     kstd::shared_ptr<devices::device> m_device{};
diff --git a/kernel/include/kernel/filesystem/ext2/ext2_file.hpp b/kernel/include/kernel/filesystem/ext2/ext2_file.hpp
new file mode 100644
index 0000000..b5708d8
--- /dev/null
+++ b/kernel/include/kernel/filesystem/ext2/ext2_file.hpp
@@ -0,0 +1,17 @@
+#ifndef TEACH_OS_KERNEL_FILESYSTEM_EXT2_FILE_HPP
+#define TEACH_OS_KERNEL_FILESYSTEM_EXT2_FILE_HPP
+
+#include "kernel/filesystem/file.hpp"
+
+#include <cstddef>
+
+namespace filesystem::ext2
+{
+  struct ext2_file : file
+  {
+    auto read(void * buffer, size_t offset, size_t size) const -> size_t override;
+    auto write(void const * buffer, size_t offset, size_t size) -> size_t override;
+  };
+}  // namespace filesystem::ext2
+
+#endif
\ No newline at end of file
diff --git a/kernel/include/kernel/filesystem/ext2/ext2_inode.hpp b/kernel/include/kernel/filesystem/ext2/ext2_inode.hpp
index 7cd6f8f..f103877 100644
--- a/kernel/include/kernel/filesystem/ext2/ext2_inode.hpp
+++ b/kernel/include/kernel/filesystem/ext2/ext2_inode.hpp
@@ -1,13 +1,21 @@
 #ifndef TEACH_OS_KERNEL_FILESYSTEM_EXT2_INODE_HPP
 #define TEACH_OS_KERNEL_FILESYSTEM_EXT2_INODE_HPP
 
+#include "kernel/filesystem/file.hpp"
 #include "kernel/filesystem/inode.hpp"
 
+#include <kstd/memory>
+
 namespace filesystem::ext2
 {
   struct ext2_inode : inode
   {
-    // TODO BA-FS26
+    ext2_inode();
+
+    [[nodiscard]] auto open_file() const -> kstd::shared_ptr<file> override;
+
+  private:
+    // TODO BA-FS26 add ext2-specific inode metadata here (e.g. block pointers, size, permissions, etc.)
   };
 }  // namespace filesystem::ext2
 
diff --git a/kernel/include/kernel/filesystem/file.hpp b/kernel/include/kernel/filesystem/file.hpp
index e7e1b12..5a41fab 100644
--- a/kernel/include/kernel/filesystem/file.hpp
+++ b/kernel/include/kernel/filesystem/file.hpp
@@ -9,8 +9,6 @@ namespace filesystem
   {
     virtual ~file() = default;
 
-    virtual auto open() -> void = 0;
-
     virtual auto read(void * buffer, size_t offset, size_t size) const -> size_t = 0;
     virtual auto write(void const * buffer, size_t offset, size_t size) -> size_t = 0;
   };
diff --git a/kernel/include/kernel/filesystem/inode.hpp b/kernel/include/kernel/filesystem/inode.hpp
index dcf83b9..79cbcf9 100644
--- a/kernel/include/kernel/filesystem/inode.hpp
+++ b/kernel/include/kernel/filesystem/inode.hpp
@@ -1,9 +1,9 @@
 #ifndef TEACH_OS_KERNEL_FILESYSTEM_INODE_HPP
 #define TEACH_OS_KERNEL_FILESYSTEM_INODE_HPP
 
-#include <kstd/memory>
+#include "kernel/filesystem/file.hpp"
 
-#include <cstddef>
+#include <kstd/memory>
 
 namespace filesystem
 {
@@ -24,8 +24,7 @@ namespace filesystem
     [[nodiscard]] auto is_regular() const -> bool;
     [[nodiscard]] auto is_device() const -> bool;
 
-    virtual auto read(void * buffer, size_t offset, size_t size) const -> size_t = 0;
-    virtual auto write(void const * buffer, size_t offset, size_t size) -> size_t = 0;
+    [[nodiscard]] virtual auto open_file() const -> kstd::shared_ptr<file> = 0;
 
   private:
     inode_kind m_kind{inode_kind::regular};
diff --git a/kernel/include/kernel/filesystem/inode_file.hpp b/kernel/include/kernel/filesystem/inode_file.hpp
deleted file mode 100644
index ee84eee..0000000
--- a/kernel/include/kernel/filesystem/inode_file.hpp
+++ /dev/null
@@ -1,27 +0,0 @@
-#ifndef TEACH_OS_KERNEL_FILESYSTEM_INODE_FILE_HPP
-#define TEACH_OS_KERNEL_FILESYSTEM_INODE_FILE_HPP
-
-#include "kernel/filesystem/file.hpp"
-#include "kernel/filesystem/inode.hpp"
-
-#include <kstd/memory>
-
-#include <cstddef>
-
-namespace filesystem
-{
-  struct inode_file : file
-  {
-    explicit inode_file(kstd::shared_ptr<inode> const & inode);
-
-    auto open() -> void override;
-
-    auto read(void * buffer, size_t offset, size_t size) const -> size_t override;
-    auto write(void const * buffer, size_t offset, size_t size) -> size_t override;
-
-  private:
-    kstd::shared_ptr<inode> m_inode;
-  };
-}  // namespace filesystem
-
-#endif
\ No newline at end of file
diff --git a/kernel/src/filesystem/device_file.cpp b/kernel/src/filesystem/device_file.cpp
index c6db5af..48ed20d 100644
--- a/kernel/src/filesystem/device_file.cpp
+++ b/kernel/src/filesystem/device_file.cpp
@@ -23,11 +23,6 @@ namespace filesystem
     }
   }
 
-  auto device_file::open() -> void
-  {
-    // Hook point for permission checks or lazy metadata loading.
-  }
-
   auto device_file::read(void * buffer, size_t offset, size_t size) const -> size_t
   {
     if (m_device->is_block_device())
diff --git a/kernel/src/filesystem/device_inode.cpp b/kernel/src/filesystem/device_inode.cpp
index 18e3b24..592637d 100644
--- a/kernel/src/filesystem/device_inode.cpp
+++ b/kernel/src/filesystem/device_inode.cpp
@@ -3,12 +3,12 @@
 #include "kapi/system.hpp"
 
 #include "kernel/devices/device.hpp"
+#include "kernel/filesystem/device_file.hpp"
+#include "kernel/filesystem/file.hpp"
 #include "kernel/filesystem/inode.hpp"
 
 #include <kstd/memory>
 
-#include <cstddef>
-
 namespace filesystem
 {
   device_inode::device_inode(kstd::shared_ptr<devices::device> const & device)
@@ -21,32 +21,8 @@ namespace filesystem
     }
   }
 
-  auto device_inode::backing_device() const -> kstd::shared_ptr<devices::device> const &
-  {
-    return m_device;
-  }
-
-  auto device_inode::read(void * /*buffer*/, size_t /*offset*/, size_t /*size*/) const -> size_t
+  auto device_inode::open_file() const -> kstd::shared_ptr<file>
   {
-    if (!m_device)
-    {
-      kapi::system::panic("[FILESYSTEM] device_inode has null device.");
-    }
-
-    // TODO BA-FS26 use device file?
-    // return m_device->read(buffer, offset, size);
-    return 0;
-  }
-
-  auto device_inode::write(void const * /*buffer*/, size_t /*offset*/, size_t /*size*/) -> size_t
-  {
-    if (!m_device)
-    {
-      kapi::system::panic("[FILESYSTEM] device_inode has null device.");
-    }
-
-    // TODO BA-FS26 use device file?
-    // return m_device->write(buffer, offset, size);
-    return 0;
+    return kstd::make_shared<device_file>(m_device);
   }
 }  // namespace filesystem
\ No newline at end of file
diff --git a/kernel/src/filesystem/ext2/ext2_file.cpp b/kernel/src/filesystem/ext2/ext2_file.cpp
new file mode 100644
index 0000000..7217c77
--- /dev/null
+++ b/kernel/src/filesystem/ext2/ext2_file.cpp
@@ -0,0 +1,20 @@
+#include "kernel/filesystem/ext2/ext2_file.hpp"
+
+#include "kapi/system.hpp"
+
+#include <cstddef>
+
+namespace filesystem::ext2
+{
+  auto ext2_file::read(void * /*buffer*/, size_t /*offset*/, size_t /*size*/) const -> size_t
+  {
+    kapi::system::panic("[FILESYSTEM] ext2_file::read is not implemented yet.");
+    return 0;
+  }
+
+  auto ext2_file::write(void const * /*buffer*/, size_t /*offset*/, size_t /*size*/) -> size_t
+  {
+    kapi::system::panic("[FILESYSTEM] ext2_file::write is not implemented yet.");
+    return 0;
+  }
+}  // namespace filesystem::ext2
diff --git a/kernel/src/filesystem/ext2/ext2_inode.cpp b/kernel/src/filesystem/ext2/ext2_inode.cpp
index ec68ee9..1522387 100644
--- a/kernel/src/filesystem/ext2/ext2_inode.cpp
+++ b/kernel/src/filesystem/ext2/ext2_inode.cpp
@@ -1,6 +1,19 @@
 #include "kernel/filesystem/ext2/ext2_inode.hpp"
 
+#include "kernel/filesystem/ext2/ext2_file.hpp"
+#include "kernel/filesystem/file.hpp"
+#include "kernel/filesystem/inode.hpp"
+
+#include <kstd/memory>
+
 namespace filesystem::ext2
 {
-  // TODO BA-FS26: Implement ext2 inode
-}
\ No newline at end of file
+  ext2_inode::ext2_inode()
+      : inode(inode_kind::regular)
+  {}
+
+  auto ext2_inode::open_file() const -> kstd::shared_ptr<file>
+  {
+    return kstd::make_shared<ext2_file>();
+  }
+}  // namespace filesystem::ext2
\ No newline at end of file
diff --git a/kernel/src/filesystem/inode_file.cpp b/kernel/src/filesystem/inode_file.cpp
deleted file mode 100644
index 7abac7b..0000000
--- a/kernel/src/filesystem/inode_file.cpp
+++ /dev/null
@@ -1,35 +0,0 @@
-#include "kernel/filesystem/inode_file.hpp"
-
-#include "kapi/system.hpp"
-
-#include "kernel/filesystem/inode.hpp"
-
-#include <kstd/memory>
-
-#include <cstddef>
-
-namespace filesystem
-{
-  inode_file::inode_file(kstd::shared_ptr<inode> const & inode)
-      : m_inode(inode)
-  {
-    if (!m_inode)
-    {
-      kapi::system::panic("[FILESYSTEM] inode_file constructed with null inode");
-    }
-  }
-
-  auto inode_file::open() -> void
-  {
-    // Hook point for permission checks or lazy metadata loading.
-  }
-
-  auto inode_file::read(void * buffer, size_t offset, size_t size) const -> size_t
-  {
-    return m_inode->read(buffer, offset, size);
-  }
-  auto inode_file::write(void const * buffer, size_t offset, size_t size) -> size_t
-  {
-    return m_inode->write(buffer, offset, size);
-  }
-}  // namespace filesystem
\ No newline at end of file
diff --git a/kernel/src/filesystem/vfs.cpp b/kernel/src/filesystem/vfs.cpp
index 188da6d..4b0c7d7 100644
--- a/kernel/src/filesystem/vfs.cpp
+++ b/kernel/src/filesystem/vfs.cpp
@@ -5,11 +5,8 @@
 #include "kernel/devices/device.hpp"
 #include "kernel/devices/storage/storage_management.hpp"
 #include "kernel/filesystem/custody.hpp"
-#include "kernel/filesystem/device_file.hpp"
 #include "kernel/filesystem/device_inode.hpp"
 #include "kernel/filesystem/ext2/ext2_filesystem.hpp"
-#include "kernel/filesystem/inode.hpp"
-#include "kernel/filesystem/inode_file.hpp"
 #include "kernel/filesystem/mount.hpp"
 #include "kernel/filesystem/open_file_description.hpp"
 
@@ -71,16 +68,13 @@ namespace filesystem
     if (auto custody = resolve_path(path))
     {
       auto node = custody->get_inode();
-      if (node->is_device())
+
+      auto current_inode_file = node->open_file();
+      if (!current_inode_file)
       {
-        auto device_node = static_cast<device_inode *>(node.get());
-        auto current_device_file = kstd::make_shared<device_file>(device_node->backing_device());
-        current_device_file->open();
-        return open_file_description{current_device_file};
+        kapi::system::panic("[FILESYSTEM] inode::open_file returned null file.");
       }
 
-      auto current_inode_file = kstd::make_shared<inode_file>(node);
-      current_inode_file->open();
       return open_file_description{current_inode_file};
     }