MaxOS::filesystem::format::Fat32Directory Class Reference

Handles the directory operations on the FAT32 filesystem. More...

#include <fat32.h>

Inheritance diagram for MaxOS::filesystem::format::Fat32Directory:

Public Member Functions
	Fat32Directory (Fat32Volume *volume, lba_t cluster, const string &name)
	Construct a new Fat32 Directory object.
void	read_from_disk () final
	read the directory from the disk
File *	create_file (const string &name) final
	Create a new file in the directory.
void	remove_file (const string &name) final
	Delete a file from the subdirectory.
Directory *	create_subdirectory (const string &name) final
	Create a new directory in the directory.
void	remove_subdirectory (const string &name) final
	Remove a directory entry from the directory.
lba_t	first_cluster () const
	Get the first cluster of the directory.
Public Member Functions inherited from MaxOS::filesystem::Directory
virtual	~Directory ()
	Destructor for Directory, frees all files and subdirectories.
common::Vector< File * >	files ()
	Get the files in the directory.
common::Vector< Directory * >	subdirectories ()
	Get the subdirectories in the directory.
File *	open_file (const string &name)
	Open a file in the directory.
Directory *	open_subdirectory (const string &name)
	Open a directory in the directory.
void	rename_file (File *file, const string &new_name)
	Rename a file in the directory.
virtual void	rename_file (const string &old_name, const string &new_name)
	Rename a file in the directory.
void	rename_subdirectory (Directory *directory, const string &new_name)
	Rename a subdirectory in the directory.
virtual void	rename_subdirectory (const string &old_name, const string &new_name)
	Rename a subdirectory in the directory.
string	name ()
	Get the name of the directory.
size_t	size ()
	Get the size of the directory.

Protected Member Functions
void	save_entry_to_disk (dir_entry_t *entry)
	Writes an updated directory entry to the disk.
void	update_entry_on_disk (size_t index)
	Save the directory entry at the given index to the disk.

Friends
class	Fat32File

Additional Inherited Members
Protected Attributes inherited from MaxOS::filesystem::Directory
common::Vector< File * >	m_files
	The files in this directory.
common::Vector< Directory * >	m_subdirectories
	The subdirectories in this directory.
string	m_name
	The name of this directory.

Detailed Description

Handles the directory operations on the FAT32 filesystem.

Definition at line 235 of file fat32.h.

Constructor & Destructor Documentation

Fat32Directory()

Fat32Directory::Fat32Directory	(	Fat32Volume *	volume,
		lba_t	cluster,
		const string &	name
	)

Construct a new Fat32 Directory object.

Parameters

volume	The FAT32 volume
cluster	The cluster of the directory
name	The name of the directory

Definition at line 424 of file fat32.cpp.

        : m_volume(volume),
        m_first_cluster(cluster) {
    m_name = name;
}

References MaxOS::filesystem::Directory::m_name, and MaxOS::filesystem::Directory::name().

Member Function Documentation

create_file()

File * Fat32Directory::create_file ( const string &  name )

finalvirtual

Create a new file in the directory.

Parameters

name	The name of the file to create

Returns

The new file object or null if it could not be created

Reimplemented from MaxOS::filesystem::Directory.

Definition at line 890 of file fat32.cpp.

                                                    {
 
    // Check if the file already exists
    for(auto& file : m_files)
        if(file->name() == name)
            return nullptr;
 
    // Check if the name is too long
    if(name.length() > MAX_NAME_LENGTH)
        return nullptr;
 
    // Create the file
    auto file = new Fat32File(m_volume, this, create_entry(name, false), name);
    m_files.push_back(file);
    return file;
}

References MaxOS::filesystem::Directory::m_files, MaxOS::filesystem::format::MAX_NAME_LENGTH, and MaxOS::filesystem::Directory::name().

create_subdirectory()

Directory * Fat32Directory::create_subdirectory ( const string &  name )

finalvirtual

Create a new directory in the directory.

Parameters

name	The name of the directory to create

Returns

The new directory object or null if it could not be created

Reimplemented from MaxOS::filesystem::Directory.

Definition at line 933 of file fat32.cpp.

                                                                 {
 
    // Check if the directory already exists
    for(auto& subdirectory : m_subdirectories)
        if(subdirectory->name() == name)
            return nullptr;
 
    // Check if the name is too long
    if(name.length() > MAX_NAME_LENGTH)
        return nullptr;
 
    // Create the directory
    auto entry = create_entry(name, true);
    uint32_t cluster = ((entry->first_cluster_high << 16) | entry->first_cluster_low);
 
    // Store the directory
    auto directory = new Fat32Directory(m_volume, cluster, name);
    m_subdirectories.push_back(directory);
    return directory;
}

References MaxOS::filesystem::Directory::m_subdirectories, MaxOS::filesystem::format::MAX_NAME_LENGTH, and MaxOS::filesystem::Directory::name().

first_cluster()

lba_t MaxOS::filesystem::format::Fat32Directory::first_cluster ( ) const

inline

Get the first cluster of the directory.

Returns

The first cluster of the directory

Definition at line 279 of file fat32.h.

{ return m_first_cluster; }

Referenced by remove_file(), and remove_subdirectory().

read_from_disk()

void Fat32Directory::read_from_disk ( )

finalvirtual

read the directory from the disk

Reimplemented from MaxOS::filesystem::Directory.

Definition at line 829 of file fat32.cpp.

                                    {
 
    for(auto& file : m_files)
        delete file;
    m_files.clear();
 
    for(auto& directory : m_subdirectories)
        delete directory;
    m_subdirectories.clear();
 
    // Load the entries from the disk into memory
    read_all_entries();
 
    // Parse the entries
    string long_name = "";
    for(auto& entry : m_entries) {
 
        // Skip free entries and volume labels
        if(entry.name[0] == (uint8_t) DirectoryEntryType::FREE
           || entry.attributes == (uint8_t) DirectoryEntryAttributes::FREE
           || entry.attributes == (uint8_t) DirectoryEntryAttributes::VOLUME_ID)
            continue;
 
        // Extract the long name
        if(entry.attributes == (uint8_t) DirectoryEntryAttributes::LONG_NAME) {
            long_name = parse_long_filename((long_file_name_entry_t*) &entry, long_name);
            continue;
        }
 
        bool is_directory = entry.attributes == (uint8_t) DirectoryEntryAttributes::DIRECTORY;
 
        // Get the name of the entry
        string name = long_name;
        if(long_name == "") {
            name = string(entry.name, 8);
 
            // Add the extension
            if(!is_directory)
                name = name.strip() + "." + string(entry.extension, 3);
        }
 
        long_name = "";
 
        // Get the starting cluster
        uint32_t start_cluster = (entry.first_cluster_high << 16) | entry.first_cluster_low;
 
        // Store the file or directory
        if(is_directory)
            m_subdirectories.push_back(new Fat32Directory(m_volume, start_cluster, name.strip()));
        else
            m_files.push_back(new Fat32File(m_volume, this, &entry, name));
 
    }
}

References MaxOS::filesystem::Directory::m_files, MaxOS::filesystem::Directory::m_subdirectories, and MaxOS::filesystem::Directory::name().

remove_file()

void Fat32Directory::remove_file ( const string &  name )

finalvirtual

Delete a file from the subdirectory.

Parameters

name	The name of the file to delete

Reimplemented from MaxOS::filesystem::Directory.

Definition at line 912 of file fat32.cpp.

                                                   {
    // Find the file if it exists
    for(auto& file : m_files)
        if(file->name() == name) {
 
            // Remove the file from the directory
            m_files.erase(file);
            remove_entry(((Fat32File*) file)->first_cluster());
 
            // Delete the file reference
            delete file;
            return;
        }
}

References first_cluster(), MaxOS::filesystem::Directory::m_files, and MaxOS::filesystem::Directory::name().

remove_subdirectory()

void Fat32Directory::remove_subdirectory ( const string &  name )

finalvirtual

Remove a directory entry from the directory.

Parameters

name	The name of the entry to remove

Reimplemented from MaxOS::filesystem::Directory.

Definition at line 959 of file fat32.cpp.

                                                           {
    // Find the directory if it exists
    for(auto& subdirectory : m_subdirectories) {
        if(subdirectory->name() != name)
            continue;
 
        // Remove all the files in the directory
        for(auto& file : subdirectory->files())
            subdirectory->remove_file(file->name());
 
        // Remove all the subdirectories in the directory
        for(auto& child_dir : subdirectory->subdirectories())
            child_dir->remove_subdirectory(child_dir->name());
 
        // Remove the entry
        m_subdirectories.erase(subdirectory);
        remove_entry(((Fat32Directory*) subdirectory)->first_cluster());
 
        // Delete the directory
        delete subdirectory;
        return;
    }
}

References first_cluster(), MaxOS::filesystem::Directory::m_subdirectories, and MaxOS::filesystem::Directory::name().

save_entry_to_disk()

void Fat32Directory::save_entry_to_disk ( dir_entry_t *  entry )

protected

Writes an updated directory entry to the disk.

Parameters

entry

The entry to write

Definition at line 589 of file fat32.cpp.

                                                             {
 
    int index = 0;
    for(auto& m_entry : m_entries) {
        if(&m_entry == entry)
            break;
        index++;
    }
 
    update_entry_on_disk(index);
}

References update_entry_on_disk().

Referenced by MaxOS::filesystem::format::Fat32File::write().

update_entry_on_disk()

void Fat32Directory::update_entry_on_disk ( size_t  index )

protected

Save the directory entry at the given index to the disk.

Parameters

index

The index of the entry to update

Definition at line 605 of file fat32.cpp.

                                                      {
 
    // Get the entry
    auto entry = m_entries[index];
 
    // Determine sector offset and in-sector byte offset
    uint32_t bytes_per_sector = m_volume->bpb.bytes_per_sector;
    uint32_t entry_offset = index * sizeof(dir_entry_t);
    uint32_t sector_offset = entry_offset / bytes_per_sector;
    uint32_t in_sector_offset = entry_offset % bytes_per_sector;
 
    // Find which cluster has the entry
    uint32_t cluster = m_first_cluster;
    for(uint32_t offset_remaining = entry_offset;
        offset_remaining >= bytes_per_sector; offset_remaining -= bytes_per_sector)
        cluster = m_volume->next_cluster(cluster);
 
    // Read the full sector into a buffer
    lba_t base_lba = m_volume->data_lba + (cluster - 2) * m_volume->bpb.sectors_per_cluster;
    buffer_t sector_buffer(bytes_per_sector, false);
    m_volume->disk->read(base_lba + sector_offset, &sector_buffer);
 
    // Update the entry in the buffer
    sector_buffer.copy_from(&entry, sizeof(dir_entry_t), in_sector_offset);
    m_volume->disk->write(base_lba + sector_offset, &sector_buffer);
}

References MaxOS::filesystem::format::Fat32Volume::bpb, MaxOS::filesystem::format::Fat32Volume::data_lba, MaxOS::filesystem::format::Fat32Volume::disk, MaxOS::filesystem::format::Fat32Volume::next_cluster(), MaxOS::drivers::disk::Disk::read(), and MaxOS::drivers::disk::Disk::write().

Referenced by save_entry_to_disk().

Friends And Related Symbol Documentation

Fat32File

friend class Fat32File

friend

Definition at line 236 of file fat32.h.

---

The documentation for this class was generated from the following files:

• /home/runner/work/MaxOS/MaxOS/kernel/include/filesystem/format/fat32.h
• /home/runner/work/MaxOS/MaxOS/kernel/src/filesystem/format/fat32.cpp