path: root/Source/Kernel/VFS/File.class.cpp

#include "File.class.h"
#include <VFS/VFS.ns.h>
#include <TaskManager/Task.ns.h>

File::File() : m_file(NULL), m_valid(false), m_writable(false), m_position(0) {
}

File::File(String filename, u8int mode, FSNode* start) :
	m_file(NULL), m_valid(false), m_writable(false), m_position(0) {
	open(filename, mode, start);
}

File::~File() {
	close();
}

bool File::open(String filename, u8int mode, FSNode* start) {
	if (m_valid) return false;

	FSNode* node = VFS::find(filename, start);
	if (node == NULL) return false;
	if (node->type() != NT_FILE) return false;

	m_file = (FileNode*) node;

	m_writable = (mode != FM_READ);
	if (!m_file->writable() and m_writable) return false;

	if (mode == FM_READ or mode == FM_REPLACE) {
		m_position = 0;
	} else if (mode == FM_TRUNCATE) {
		if (!m_file->truncate()) return false;
		m_position = 0;
	} else if (mode == FM_APPEND) {
		m_position = m_file->getLength();
	}

	if (m_writable)
		m_file->m_readers++;
	else
		m_file->m_writers++;

	Task::currentProcess->registerFileDescriptor(this);
	m_valid = true;
	return true;
}

u32int File::read(u32int max_length, u8int *data) {
	if (!m_valid) return 0;
	u32int l = m_file->read(m_position, max_length, data);
	m_position += l;
	return l;
}

bool File::write(u32int length, u8int *data) {
	if (!m_valid) return false;
	if (!m_writable) return false;
	if (m_file->write(m_position, length, data)) {
		m_position += length;
		return true;
	}
	return false;
}

bool File::seek(u64int count, u8int mode) {
	if (!m_valid) return false;
	if (mode == SM_FORWARD) {
		if (m_position + count <= m_file->getLength()) {
			m_position += count;
			return true;
		} else {
			return false;
		}
	} else if (mode == SM_BACKWARD) {
		if (count <= m_position) {
			m_position -= count;
			return true;
		} else {
			return false;
		}
	} else if (mode == SM_BEGINNING) {
		if (count <= m_file->getLength()) {
			m_position = count;
			return true;
		} else {
			return false;
		}
	} else if (mode == SM_END) {
		if (count <= m_file->getLength()) {
			m_position = m_file->getLength() - count;
			return true;
		} else {
			return false;
		}
	}
	return false;
}

void File::close(bool unregisterFD) {
	if (!m_valid) return;
	if (m_writable)
		m_file->m_writers--;
	else
		m_file->m_readers--;
	m_valid = false;
	m_file = NULL;
	m_position = 0;
	m_writable = false;
	if (unregisterFD) Task::currentProcess->unregisterFileDescriptor(this);
}