ocarina/core/file.c

/*
 * Copyright 2013 (c) Anna Schumaker.
 */
#include <core/file.h>
#include <core/string.h>
#include <core/version.h>
#include <errno.h>
#include <unistd.h>

#define REPORT_ERROR(fname, error) \
	g_printerr("%s (%s:%d): %s: %s\n", __func__, __FILE__, __LINE__, fname, error)
#define REPORT_ERRNO(fname) REPORT_ERROR(fname, strerror(errno))

static gchar *__file_path(const gchar *name)
{
	return g_strjoin("/", g_get_user_data_dir(), OCARINA_NAME, name, NULL);
}

static FILE *__file_open(gchar *path, const gchar *mode)
{
	FILE *ret = g_fopen(path, mode);

	if (!ret)
		REPORT_ERRNO(path);
	g_free(path);
	return ret;
}

static bool __file_mkdir()
{
	gchar *dir = __file_path(NULL);
	int    ret = g_mkdir_with_parents(dir, 0755);

	if (ret != 0)
		REPORT_ERRNO(dir);
	g_free(dir);
	return ret == 0;
}

static bool __file_can_write(struct file *file)
{
	gchar *path = file_path(file);
	bool   ret  = true;

	if (g_access(path, F_OK) == 0 && g_access(path, W_OK) < 0)
		ret = false;

	g_free(path);
	return ret;
}

static void __file_rename_tmp(struct file *file)
{
	gchar *path = file_path(file);
	gchar *real = file_write_path(file);

	g_rename(real, path);

	g_free(real);
	g_free(path);
}


void file_init(struct file *file,    const gchar *name,
	       unsigned int version, unsigned int min)
{
	file->f_mode = OPEN_READ;
	file->f_version = version;
	file->f_prev = 0;
	file->f_min  = 0;
	file->f_file = NULL;
	file->f_name = name;
}

gchar *file_path(struct file *file)
{
	if (string_length(file->f_name) != 0)
		return __file_path(file->f_name);
	return g_strdup("");
}

gchar *file_write_path(struct file *file)
{
	gchar *fname, *res;

	if (string_length(file->f_name) == 0)
		return g_strdup("");

	fname = g_strdup_printf(".%s.tmp", file->f_name);
	res   = __file_path(fname);
	g_free(fname);

	return res;
}

const unsigned int file_version(struct file *file)
{
	if (file->f_file && (file->f_mode == OPEN_READ))
		return file->f_prev;
	return file->f_version;
}

bool file_exists(struct file *file)
{
	gchar *path = file_path(file);
	bool    ret = g_file_test(path, G_FILE_TEST_EXISTS);

	g_free(path);
	return ret;
}

static bool __file_open_read(struct file *file)
{
	if (!file_exists(file))
		return false;

	file->f_file = __file_open(file_path(file), "r");
	if (!file->f_file)
		return false;

	file->f_mode = OPEN_READ;
	if (file_readf(file, "%u\n", &file->f_prev) != 1)
		return false;
	if (file->f_prev < file->f_min) {
		REPORT_ERROR(file->f_name, "File too old to be upgraded.");
		file_close(file);
		return false;
	}
	return true;
}

static bool __file_open_write(struct file *file)
{
	if (!__file_mkdir())
		return false;
	if (!__file_can_write(file))
		return false;

	file->f_file = __file_open(file_write_path(file), "w");
	if (!file->f_file)
		return false;

	file->f_mode = OPEN_WRITE;
	return file_writef(file, "%d\n", file->f_version) > 0;
}

bool file_open(struct file *file, enum open_mode mode)
{
	if ((string_length(file->f_name) == 0) || (file->f_file != NULL))
		return false;

	if (mode == OPEN_READ)
		return __file_open_read(file);
	return __file_open_write(file);
}

void file_close(struct file *file)
{
	if (file->f_file) {
		fclose(file->f_file);
		if (file->f_mode == OPEN_WRITE)
			__file_rename_tmp(file);
	}
	file->f_file = NULL;
}

int file_readf(struct file *file, const char *fmt, ...)
{
	va_list argp;
	int ret;

	va_start(argp, fmt);
	ret = vfscanf(file->f_file, fmt, argp);
	va_end(argp);

	return ret;
}

gchar *file_readl(struct file *file)
{
	gchar *res;

	if (file_readf(file, "%m[^\n]\n", &res) == 0)
		return g_strdup("");

	g_strstrip(res);
	return res;
}

int file_writef(struct file *file, const char *fmt, ...)
{
	va_list argp;
	int ret;

	va_start(argp, fmt);
	ret = g_vfprintf(file->f_file, fmt, argp);
	va_end(argp);

	if (ret < 0)
		REPORT_ERRNO(file->f_name);
	return ret;
}