/*************************************************************************/
/*  file_access.cpp                                                      */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                      https://godotengine.org                          */
/*************************************************************************/
/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md).   */
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/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the       */
/* "Software"), to deal in the Software without restriction, including   */
/* without limitation the rights to use, copy, modify, merge, publish,   */
/* distribute, sublicense, and/or sell copies of the Software, and to    */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions:                                             */
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/* The above copyright notice and this permission notice shall be        */
/* included in all copies or substantial portions of the Software.       */
/*                                                                       */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
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/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
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/*************************************************************************/

#include "file_access.h"

#include "core/config/project_settings.h"
#include "core/crypto/crypto_core.h"
#include "core/io/file_access_pack.h"
#include "core/io/marshalls.h"
#include "core/os/os.h"

FileAccess::CreateFunc FileAccess::create_func[ACCESS_MAX] = { nullptr, nullptr };

FileAccess::FileCloseFailNotify FileAccess::close_fail_notify = nullptr;

bool FileAccess::backup_save = false;

Ref<FileAccess> FileAccess::create(AccessType p_access) {
	ERR_FAIL_INDEX_V(p_access, ACCESS_MAX, nullptr);

	Ref<FileAccess> ret = create_func[p_access]();
	ret->_set_access_type(p_access);
	return ret;
}

bool FileAccess::exists(const String &p_name) {
	if (PackedData::get_singleton() && !PackedData::get_singleton()->is_disabled() && PackedData::get_singleton()->has_path(p_name)) {
		return true;
	}

	Ref<FileAccess> f = open(p_name, READ);
	if (f.is_null()) {
		return false;
	}
	return true;
}

void FileAccess::_set_access_type(AccessType p_access) {
	_access_type = p_access;
}

Ref<FileAccess> FileAccess::create_for_path(const String &p_path) {
	Ref<FileAccess> ret;
	if (p_path.begins_with("res://")) {
		ret = create(ACCESS_RESOURCES);
	} else if (p_path.begins_with("user://")) {
		ret = create(ACCESS_USERDATA);

	} else {
		ret = create(ACCESS_FILESYSTEM);
	}

	return ret;
}

Error FileAccess::reopen(const String &p_path, int p_mode_flags) {
	return _open(p_path, p_mode_flags);
}

Ref<FileAccess> FileAccess::open(const String &p_path, int p_mode_flags, Error *r_error) {
	//try packed data first

	Ref<FileAccess> ret;
	if (!(p_mode_flags & WRITE) && PackedData::get_singleton() && !PackedData::get_singleton()->is_disabled()) {
		ret = PackedData::get_singleton()->try_open_path(p_path);
		if (ret.is_valid()) {
			if (r_error) {
				*r_error = OK;
			}
			return ret;
		}
	}

	ret = create_for_path(p_path);
	Error err = ret->_open(p_path, p_mode_flags);

	if (r_error) {
		*r_error = err;
	}
	if (err != OK) {
		ret.unref();
	}

	return ret;
}

FileAccess::CreateFunc FileAccess::get_create_func(AccessType p_access) {
	return create_func[p_access];
}

String FileAccess::fix_path(const String &p_path) const {
	//helper used by file accesses that use a single filesystem

	String r_path = p_path.replace("\\", "/");

	switch (_access_type) {
		case ACCESS_RESOURCES: {
			if (ProjectSettings::get_singleton()) {
				if (r_path.begins_with("res://")) {
					String resource_path = ProjectSettings::get_singleton()->get_resource_path();
					if (!resource_path.is_empty()) {
						return r_path.replace("res:/", resource_path);
					}
					return r_path.replace("res://", "");
				}
			}

		} break;
		case ACCESS_USERDATA: {
			if (r_path.begins_with("user://")) {
				String data_dir = OS::get_singleton()->get_user_data_dir();
				if (!data_dir.is_empty()) {
					return r_path.replace("user:/", data_dir);
				}
				return r_path.replace("user://", "");
			}

		} break;
		case ACCESS_FILESYSTEM: {
			return r_path;
		} break;
		case ACCESS_MAX:
			break; // Can't happen, but silences warning
	}

	return r_path;
}

/* these are all implemented for ease of porting, then can later be optimized */

uint16_t FileAccess::get_16() const {
	uint16_t res;
	uint8_t a, b;

	a = get_8();
	b = get_8();

	if (big_endian) {
		SWAP(a, b);
	}

	res = b;
	res <<= 8;
	res |= a;

	return res;
}

uint32_t FileAccess::get_32() const {
	uint32_t res;
	uint16_t a, b;

	a = get_16();
	b = get_16();

	if (big_endian) {
		SWAP(a, b);
	}

	res = b;
	res <<= 16;
	res |= a;

	return res;
}

uint64_t FileAccess::get_64() const {
	uint64_t res;
	uint32_t a, b;

	a = get_32();
	b = get_32();

	if (big_endian) {
		SWAP(a, b);
	}

	res = b;
	res <<= 32;
	res |= a;

	return res;
}

float FileAccess::get_float() const {
	MarshallFloat m;
	m.i = get_32();
	return m.f;
}

real_t FileAccess::get_real() const {
	if (real_is_double) {
		return get_double();
	} else {
		return get_float();
	}
}

double FileAccess::get_double() const {
	MarshallDouble m;
	m.l = get_64();
	return m.d;
}

String FileAccess::get_token() const {
	CharString token;

	char32_t c = get_8();

	while (!eof_reached()) {
		if (c <= ' ') {
			if (token.length()) {
				break;
			}
		} else {
			token += c;
		}
		c = get_8();
	}

	return String::utf8(token.get_data());
}

class CharBuffer {
	Vector<char> vector;
	char stack_buffer[256];

	char *buffer = nullptr;
	int capacity = 0;
	int written = 0;

	bool grow() {
		if (vector.resize(next_power_of_2(1 + written)) != OK) {
			return false;
		}

		if (buffer == stack_buffer) { // first chunk?

			for (int i = 0; i < written; i++) {
				vector.write[i] = stack_buffer[i];
			}
		}

		buffer = vector.ptrw();
		capacity = vector.size();
		ERR_FAIL_COND_V(written >= capacity, false);

		return true;
	}

public:
	_FORCE_INLINE_ CharBuffer() :
			buffer(stack_buffer),
			capacity(sizeof(stack_buffer) / sizeof(char)) {
	}

	_FORCE_INLINE_ void push_back(char c) {
		if (written >= capacity) {
			ERR_FAIL_COND(!grow());
		}

		buffer[written++] = c;
	}

	_FORCE_INLINE_ const char *get_data() const {
		return buffer;
	}
};

String FileAccess::get_line() const {
	CharBuffer line;

	char32_t c = get_8();

	while (!eof_reached()) {
		if (c == '\n' || c == '\0') {
			line.push_back(0);
			return String::utf8(line.get_data());
		} else if (c != '\r') {
			line.push_back(c);
		}

		c = get_8();
	}
	line.push_back(0);
	return String::utf8(line.get_data());
}

Vector<String> FileAccess::get_csv_line(const String &p_delim) const {
	ERR_FAIL_COND_V_MSG(p_delim.length() != 1, Vector<String>(), "Only single character delimiters are supported to parse CSV lines.");
	ERR_FAIL_COND_V_MSG(p_delim[0] == '"', Vector<String>(), "The double quotation mark character (\") is not supported as a delimiter for CSV lines.");

	String line;

	// CSV can support entries with line breaks as long as they are enclosed
	// in double quotes. So our "line" might be more than a single line in the
	// text file.
	int qc = 0;
	do {
		if (eof_reached()) {
			break;
		}
		line += get_line() + "\n";
		qc = 0;
		for (int i = 0; i < line.length(); i++) {
			if (line[i] == '"') {
				qc++;
			}
		}
	} while (qc % 2);

	// Remove the extraneous newline we've added above.
	line = line.substr(0, line.length() - 1);

	Vector<String> strings;

	bool in_quote = false;
	String current;
	for (int i = 0; i < line.length(); i++) {
		char32_t c = line[i];
		// A delimiter ends the current entry, unless it's in a quoted string.
		if (!in_quote && c == p_delim[0]) {
			strings.push_back(current);
			current = String();
		} else if (c == '"') {
			// Doubled quotes are escapes for intentional quotes in the string.
			if (line[i + 1] == '"' && in_quote) {
				current += '"';
				i++;
			} else {
				in_quote = !in_quote;
			}
		} else {
			current += c;
		}
	}
	strings.push_back(current);

	return strings;
}

uint64_t FileAccess::get_buffer(uint8_t *p_dst, uint64_t p_length) const {
	ERR_FAIL_COND_V(!p_dst && p_length > 0, -1);

	uint64_t i = 0;
	for (i = 0; i < p_length && !eof_reached(); i++) {
		p_dst[i] = get_8();
	}

	return i;
}

String FileAccess::get_as_utf8_string() const {
	Vector<uint8_t> sourcef;
	uint64_t len = get_length();
	sourcef.resize(len + 1);

	uint8_t *w = sourcef.ptrw();
	uint64_t r = get_buffer(w, len);
	ERR_FAIL_COND_V(r != len, String());
	w[len] = 0;

	String s;
	s.parse_utf8((const char *)w);
	return s;
}

void FileAccess::store_16(uint16_t p_dest) {
	uint8_t a, b;

	a = p_dest & 0xFF;
	b = p_dest >> 8;

	if (big_endian) {
		SWAP(a, b);
	}

	store_8(a);
	store_8(b);
}

void FileAccess::store_32(uint32_t p_dest) {
	uint16_t a, b;

	a = p_dest & 0xFFFF;
	b = p_dest >> 16;

	if (big_endian) {
		SWAP(a, b);
	}

	store_16(a);
	store_16(b);
}

void FileAccess::store_64(uint64_t p_dest) {
	uint32_t a, b;

	a = p_dest & 0xFFFFFFFF;
	b = p_dest >> 32;

	if (big_endian) {
		SWAP(a, b);
	}

	store_32(a);
	store_32(b);
}

void FileAccess::store_real(real_t p_real) {
	if (sizeof(real_t) == 4) {
		store_float(p_real);
	} else {
		store_double(p_real);
	}
}

void FileAccess::store_float(float p_dest) {
	MarshallFloat m;
	m.f = p_dest;
	store_32(m.i);
}

void FileAccess::store_double(double p_dest) {
	MarshallDouble m;
	m.d = p_dest;
	store_64(m.l);
}

uint64_t FileAccess::get_modified_time(const String &p_file) {
	if (PackedData::get_singleton() && !PackedData::get_singleton()->is_disabled() && (PackedData::get_singleton()->has_path(p_file) || PackedData::get_singleton()->has_directory(p_file))) {
		return 0;
	}

	Ref<FileAccess> fa = create_for_path(p_file);
	ERR_FAIL_COND_V_MSG(fa.is_null(), 0, "Cannot create FileAccess for path '" + p_file + "'.");

	uint64_t mt = fa->_get_modified_time(p_file);
	return mt;
}

uint32_t FileAccess::get_unix_permissions(const String &p_file) {
	if (PackedData::get_singleton() && !PackedData::get_singleton()->is_disabled() && (PackedData::get_singleton()->has_path(p_file) || PackedData::get_singleton()->has_directory(p_file))) {
		return 0;
	}

	Ref<FileAccess> fa = create_for_path(p_file);
	ERR_FAIL_COND_V_MSG(fa.is_null(), 0, "Cannot create FileAccess for path '" + p_file + "'.");

	uint32_t mt = fa->_get_unix_permissions(p_file);
	return mt;
}

Error FileAccess::set_unix_permissions(const String &p_file, uint32_t p_permissions) {
	if (PackedData::get_singleton() && !PackedData::get_singleton()->is_disabled() && (PackedData::get_singleton()->has_path(p_file) || PackedData::get_singleton()->has_directory(p_file))) {
		return ERR_UNAVAILABLE;
	}

	Ref<FileAccess> fa = create_for_path(p_file);
	ERR_FAIL_COND_V_MSG(fa.is_null(), ERR_CANT_CREATE, "Cannot create FileAccess for path '" + p_file + "'.");

	Error err = fa->_set_unix_permissions(p_file, p_permissions);
	return err;
}

void FileAccess::store_string(const String &p_string) {
	if (p_string.length() == 0) {
		return;
	}

	CharString cs = p_string.utf8();
	store_buffer((uint8_t *)&cs[0], cs.length());
}

void FileAccess::store_pascal_string(const String &p_string) {
	CharString cs = p_string.utf8();
	store_32(cs.length());
	store_buffer((uint8_t *)&cs[0], cs.length());
}

String FileAccess::get_pascal_string() {
	uint32_t sl = get_32();
	CharString cs;
	cs.resize(sl + 1);
	get_buffer((uint8_t *)cs.ptr(), sl);
	cs[sl] = 0;

	String ret;
	ret.parse_utf8(cs.ptr());
	return ret;
}

void FileAccess::store_line(const String &p_line) {
	store_string(p_line);
	store_8('\n');
}

void FileAccess::store_csv_line(const Vector<String> &p_values, const String &p_delim) {
	ERR_FAIL_COND(p_delim.length() != 1);

	String line = "";
	int size = p_values.size();
	for (int i = 0; i < size; ++i) {
		String value = p_values[i];

		if (value.contains("\"") || value.contains(p_delim) || value.contains("\n")) {
			value = "\"" + value.replace("\"", "\"\"") + "\"";
		}
		if (i < size - 1) {
			value += p_delim;
		}

		line += value;
	}

	store_line(line);
}

void FileAccess::store_buffer(const uint8_t *p_src, uint64_t p_length) {
	ERR_FAIL_COND(!p_src && p_length > 0);
	for (uint64_t i = 0; i < p_length; i++) {
		store_8(p_src[i]);
	}
}

Vector<uint8_t> FileAccess::get_file_as_array(const String &p_path, Error *r_error) {
	Ref<FileAccess> f = FileAccess::open(p_path, READ, r_error);
	if (f.is_null()) {
		if (r_error) { // if error requested, do not throw error
			return Vector<uint8_t>();
		}
		ERR_FAIL_V_MSG(Vector<uint8_t>(), "Can't open file from path '" + String(p_path) + "'.");
	}
	Vector<uint8_t> data;
	data.resize(f->get_length());
	f->get_buffer(data.ptrw(), data.size());
	return data;
}

String FileAccess::get_file_as_string(const String &p_path, Error *r_error) {
	Error err;
	Vector<uint8_t> array = get_file_as_array(p_path, &err);
	if (r_error) {
		*r_error = err;
	}
	if (err != OK) {
		if (r_error) {
			return String();
		}
		ERR_FAIL_V_MSG(String(), "Can't get file as string from path '" + String(p_path) + "'.");
	}

	String ret;
	ret.parse_utf8((const char *)array.ptr(), array.size());
	return ret;
}

String FileAccess::get_md5(const String &p_file) {
	Ref<FileAccess> f = FileAccess::open(p_file, READ);
	if (f.is_null()) {
		return String();
	}

	CryptoCore::MD5Context ctx;
	ctx.start();

	unsigned char step[32768];

	while (true) {
		uint64_t br = f->get_buffer(step, 32768);
		if (br > 0) {
			ctx.update(step, br);
		}
		if (br < 4096) {
			break;
		}
	}

	unsigned char hash[16];
	ctx.finish(hash);

	return String::md5(hash);
}

String FileAccess::get_multiple_md5(const Vector<String> &p_file) {
	CryptoCore::MD5Context ctx;
	ctx.start();

	for (int i = 0; i < p_file.size(); i++) {
		Ref<FileAccess> f = FileAccess::open(p_file[i], READ);
		ERR_CONTINUE(f.is_null());

		unsigned char step[32768];

		while (true) {
			uint64_t br = f->get_buffer(step, 32768);
			if (br > 0) {
				ctx.update(step, br);
			}
			if (br < 4096) {
				break;
			}
		}
	}

	unsigned char hash[16];
	ctx.finish(hash);

	return String::md5(hash);
}

String FileAccess::get_sha256(const String &p_file) {
	Ref<FileAccess> f = FileAccess::open(p_file, READ);
	if (f.is_null()) {
		return String();
	}

	CryptoCore::SHA256Context ctx;
	ctx.start();

	unsigned char step[32768];

	while (true) {
		uint64_t br = f->get_buffer(step, 32768);
		if (br > 0) {
			ctx.update(step, br);
		}
		if (br < 4096) {
			break;
		}
	}

	unsigned char hash[32];
	ctx.finish(hash);

	return String::hex_encode_buffer(hash, 32);
}