Implement resolve_path

5 files changed, 64 insertions, 10 deletions

diff --git a/kernel/include/kernel/filesystem/dentry.hpp b/kernel/include/kernel/filesystem/dentry.hpp
index db15b48..ca7ca95 100644
--- a/kernel/include/kernel/filesystem/dentry.hpp
+++ b/kernel/include/kernel/filesystem/dentry.hpp
@@ -8,6 +8,7 @@
 #include <kstd/vector>
 
 #include <cstdint>
+#include <string_view>
 
 namespace filesystem
 {
@@ -18,11 +19,14 @@ namespace filesystem
       dcache_mounted = 1 << 15
     };
 
-    dentry(kstd::shared_ptr<dentry> const & parent, kstd::shared_ptr<inode> const & node);
+    dentry(kstd::shared_ptr<dentry> const & parent, kstd::shared_ptr<inode> const & node, std::string_view name = {});
 
     [[nodiscard]] auto get_inode() const -> kstd::shared_ptr<inode> const &;
     [[nodiscard]] auto get_parent() const -> kstd::shared_ptr<dentry> const &;
 
+    auto add_child(kstd::shared_ptr<dentry> const & child) -> void;
+    [[nodiscard]] auto find_child(std::string_view name) const -> kstd::shared_ptr<dentry>;
+
     auto set_flag(dentry_flags flag) -> void;
     auto unset_flag(dentry_flags flag) -> void;
     [[nodiscard]] auto has_flag(dentry_flags flag) const -> bool;
diff --git a/kernel/include/kernel/filesystem/open_file_description.hpp b/kernel/include/kernel/filesystem/open_file_description.hpp
index 3c97d50..e17f9fe 100644
--- a/kernel/include/kernel/filesystem/open_file_description.hpp
+++ b/kernel/include/kernel/filesystem/open_file_description.hpp
@@ -11,7 +11,7 @@ namespace filesystem
 {
   struct open_file_description
   {
-    open_file_description(kstd::shared_ptr<inode> const & inode);
+    explicit open_file_description(kstd::shared_ptr<inode> const & inode);
 
     ~open_file_description() = default;
 
diff --git a/kernel/include/kernel/filesystem/vfs.hpp b/kernel/include/kernel/filesystem/vfs.hpp
index b6d4c4c..317f2d1 100644
--- a/kernel/include/kernel/filesystem/vfs.hpp
+++ b/kernel/include/kernel/filesystem/vfs.hpp
@@ -39,7 +39,7 @@ namespace filesystem
     auto init_internal() -> void;
 
     auto make_device_node(kstd::shared_ptr<devices::device> const & device) -> void;
-    [[nodiscard]] auto resolve_path(std::string_view path) -> std::optional<dentry>;
+    [[nodiscard]] auto resolve_path(std::string_view path) -> kstd::shared_ptr<dentry>;
 
     kstd::shared_ptr<filesystem> m_root_fs;
     kstd::shared_ptr<dentry> m_root_dentry;
diff --git a/kernel/src/filesystem/dentry.cpp b/kernel/src/filesystem/dentry.cpp
index e498b52..76949f2 100644
--- a/kernel/src/filesystem/dentry.cpp
+++ b/kernel/src/filesystem/dentry.cpp
@@ -6,12 +6,15 @@
 
 #include <kstd/memory>
 
+#include <algorithm>
 #include <cstdint>
+#include <string_view>
 
 namespace filesystem
 {
-  dentry::dentry(kstd::shared_ptr<dentry> const & parent, kstd::shared_ptr<inode> const & node)
-      : m_parent(parent)
+  dentry::dentry(kstd::shared_ptr<dentry> const & parent, kstd::shared_ptr<inode> const & node, std::string_view name)
+      : m_name(name)
+      , m_parent(parent)
       , m_inode(node)
   {
     if (!m_inode)
@@ -30,6 +33,17 @@ namespace filesystem
     return m_parent;
   }
 
+  auto dentry::add_child(kstd::shared_ptr<dentry> const & child) -> void
+  {
+    m_children.push_back(child);
+  }
+
+  auto dentry::find_child(std::string_view name) const -> kstd::shared_ptr<dentry>
+  {
+    auto it = std::ranges::find_if(m_children, [&](auto const & child) { return child->m_name == name; });
+    return (it != m_children.end()) ? *it : nullptr;
+  }
+
   auto dentry::set_flag(dentry_flags flag) -> void
   {
     m_flags |= static_cast<uint32_t>(flag);
diff --git a/kernel/src/filesystem/vfs.cpp b/kernel/src/filesystem/vfs.cpp
index ece3080..0e8a76d 100644
--- a/kernel/src/filesystem/vfs.cpp
+++ b/kernel/src/filesystem/vfs.cpp
@@ -15,6 +15,7 @@
 
 #include <algorithm>
 #include <optional>
+#include <ranges>
 #include <string_view>
 
 namespace filesystem
@@ -42,7 +43,6 @@ namespace filesystem
     if (auto boot_device = storage_mgmt.determine_boot_device())
     {
       m_root_fs = kstd::make_shared<ext2::ext2_filesystem>();
-
       m_root_fs->mount(boot_device);
 
       m_root_dentry = kstd::make_shared<dentry>(nullptr, m_root_fs->root_inode());
@@ -131,7 +131,7 @@ namespace filesystem
     m_device_nodes.push_back(device_node_entry{device->name().view(), kstd::make_shared<device_inode>(device)});
   }
 
-  auto vfs::resolve_path(std::string_view path) -> std::optional<dentry>
+  auto vfs::resolve_path(std::string_view path) -> kstd::shared_ptr<dentry>
   {
     // TODO BA-FS26 implement real path resolution with mounts and directories etc.
     // For now, just support device nodes at /dev/<device_name>.
@@ -148,13 +148,49 @@ namespace filesystem
 
       if (entry != m_device_nodes.end())
       {
-        return dentry{nullptr, entry->value().node};
+        return kstd::make_shared<dentry>(nullptr, entry->value().node);
       }
 
-      return std::nullopt;
+      return nullptr;
     }
+    else if (!path.empty() && path.front() == '/')
+    {
+      auto path_parts =
+          std::views::split(path, '/') | std::views::filter([](auto const & part) { return !part.empty(); });
+      auto parent = m_root_dentry;
 
-    return std::nullopt;
+      for (auto const & part : path_parts)
+      {
+        if (auto child = parent->find_child(std::string_view{part}))
+        {
+          parent = child;
+        }
+        else if (auto found_inode = m_root_fs->lookup(parent->get_inode(), std::string_view{part}))
+        {
+          auto next_dentry = kstd::make_shared<dentry>(parent, found_inode, std::string_view{part});
+          parent->add_child(next_dentry);
+          parent = next_dentry;
+        }
+        else
+        {
+          return nullptr;
+        }
+      }
+      // | std::views::transform([this](auto const & part) {
+      //     // TODO BA-FS26 implement real path resolution with mounts and directories etc.
+      //     // For now, just return null for any non-device-node path.
+      //     return std::optional<kstd::shared_ptr<dentry>>{};
+      //   })
+      // | std::views::filter([](auto const & opt) { return opt.has_value(); })
+      // | std::views::transform([](auto const & opt) { return opt.value(); })
+      // | std::ranges::find_if(m_mount_table, [&](auto const & mount) {
+      //     // TODO BA-FS26 implement real path resolution with mounts and directories etc.
+      //     // For now, just check if the first path component matches a mount point.
+      //     return part == mount.path();
+      //   });
+    }
+
+    return nullptr;
   }
 
 }  // namespace filesystem
\ No newline at end of file