// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
/*
 * Ceph - scalable distributed file system
 *
 * Copyright (C) 2011 New Dream Network
 *
 * This is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License version 2.1, as published by the Free Software
 * Foundation.  See file COPYING.
 *
 */

#include "common/escape.h"

#include <stdio.h>
#include <string.h>
#include <iomanip>
#include <boost/optional.hpp>

/*
 * Some functions for escaping RGW responses
 */

/* Static string length */
#define SSTRL(x) ((sizeof(x)/sizeof(x[0])) - 1)

#define LESS_THAN_XESCAPE		"&lt;"
#define AMPERSAND_XESCAPE		"&amp;"
#define GREATER_THAN_XESCAPE		"&gt;"
#define SGL_QUOTE_XESCAPE		"&apos;"
#define DBL_QUOTE_XESCAPE		"&quot;"

size_t escape_xml_attr_len(const char *buf)
{
	const char *b;
	size_t ret = 0;
	for (b = buf; *b; ++b) {
		unsigned char c = *b;
		switch (c) {
		case '<':
			ret += SSTRL(LESS_THAN_XESCAPE);
			break;
		case '&':
			ret += SSTRL(AMPERSAND_XESCAPE);
			break;
		case '>':
			ret += SSTRL(GREATER_THAN_XESCAPE);
			break;
		case '\'':
			ret += SSTRL(SGL_QUOTE_XESCAPE);
			break;
		case '"':
			ret += SSTRL(DBL_QUOTE_XESCAPE);
			break;
		default:
			// Escape control characters.
			if (((c < 0x20) && (c != 0x09) && (c != 0x0a)) ||
				    (c == 0x7f)) {
				ret += 6;
			}
			else {
				ret++;
			}
		}
	}
	// leave room for null terminator
	ret++;
	return ret;
}

void escape_xml_attr(const char *buf, char *out)
{
	char *o = out;
	const char *b;
	for (b = buf; *b; ++b) {
		unsigned char c = *b;
		switch (c) {
		case '<':
			memcpy(o, LESS_THAN_XESCAPE, SSTRL(LESS_THAN_XESCAPE));
			o += SSTRL(LESS_THAN_XESCAPE);
			break;
		case '&':
			memcpy(o, AMPERSAND_XESCAPE, SSTRL(AMPERSAND_XESCAPE));
			o += SSTRL(AMPERSAND_XESCAPE);
			break;
		case '>':
			memcpy(o, GREATER_THAN_XESCAPE, SSTRL(GREATER_THAN_XESCAPE));
			o += SSTRL(GREATER_THAN_XESCAPE);
			break;
		case '\'':
			memcpy(o, SGL_QUOTE_XESCAPE, SSTRL(SGL_QUOTE_XESCAPE));
			o += SSTRL(SGL_QUOTE_XESCAPE);
			break;
		case '"':
			memcpy(o, DBL_QUOTE_XESCAPE, SSTRL(DBL_QUOTE_XESCAPE));
			o += SSTRL(DBL_QUOTE_XESCAPE);
			break;
		default:
			// Escape control characters.
			if (((c < 0x20) && (c != 0x09) && (c != 0x0a)) ||
				    (c == 0x7f)) {
				snprintf(o, 7, "&#x%02x;", c);
				o += 6;
			}
			else {
				*o++ = c;
			}
			break;
		}
	}
	// null terminator
	*o = '\0';
}

// applies hex formatting on construction, restores on destruction
struct hex_formatter {
  std::ostream& out;
  const char old_fill;
  const std::ostream::fmtflags old_flags;

  explicit hex_formatter(std::ostream& out)
    : out(out),
      old_fill(out.fill('0')),
      old_flags(out.setf(out.hex, out.basefield))
  {}
  ~hex_formatter() {
    out.fill(old_fill);
    out.flags(old_flags);
  }
};

std::ostream& operator<<(std::ostream& out, const xml_stream_escaper& e)
{
  boost::optional<hex_formatter> fmt;

  for (unsigned char c : e.str) {
    switch (c) {
    case '<':
      out << LESS_THAN_XESCAPE;
      break;
    case '&':
      out << AMPERSAND_XESCAPE;
      break;
    case '>':
      out << GREATER_THAN_XESCAPE;
      break;
    case '\'':
      out << SGL_QUOTE_XESCAPE;
      break;
    case '"':
      out << DBL_QUOTE_XESCAPE;
      break;
    default:
      // Escape control characters.
      if (((c < 0x20) && (c != 0x09) && (c != 0x0a)) || (c == 0x7f)) {
        if (!fmt) {
          fmt.emplace(out); // enable hex formatting
        }
        out << "&#x" << std::setw(2) << static_cast<unsigned int>(c) << ';';
      } else {
        out << c;
      }
      break;
    }
  }
  return out;
}

#define DBL_QUOTE_JESCAPE "\\\""
#define BACKSLASH_JESCAPE "\\\\"
#define TAB_JESCAPE "\\t"
#define NEWLINE_JESCAPE "\\n"

size_t escape_json_attr_len(const char *buf, size_t src_len)
{
	const char *b;
	size_t i, ret = 0;
	for (i = 0, b = buf; i < src_len; ++i, ++b) {
		unsigned char c = *b;
		switch (c) {
		case '"':
			ret += SSTRL(DBL_QUOTE_JESCAPE);
			break;
		case '\\':
			ret += SSTRL(BACKSLASH_JESCAPE);
			break;
		case '\t':
			ret += SSTRL(TAB_JESCAPE);
			break;
		case '\n':
			ret += SSTRL(NEWLINE_JESCAPE);
			break;
		default:
			// Escape control characters.
			if ((c < 0x20) || (c == 0x7f)) {
				ret += 6;
			}
			else {
				ret++;
			}
		}
	}
	// leave room for null terminator
	ret++;
	return ret;
}

void escape_json_attr(const char *buf, size_t src_len, char *out)
{
	char *o = out;
	const char *b;
	size_t i;
	for (i = 0, b = buf; i < src_len; ++i, ++b) {
		unsigned char c = *b;
		switch (c) {
		case '"':
			// cppcheck-suppress invalidFunctionArg
			memcpy(o, DBL_QUOTE_JESCAPE, SSTRL(DBL_QUOTE_JESCAPE));
			o += SSTRL(DBL_QUOTE_JESCAPE);
			break;
		case '\\':
			// cppcheck-suppress invalidFunctionArg
			memcpy(o, BACKSLASH_JESCAPE, SSTRL(BACKSLASH_JESCAPE));
			o += SSTRL(BACKSLASH_JESCAPE);
			break;
		case '\t':
			// cppcheck-suppress invalidFunctionArg
			memcpy(o, TAB_JESCAPE, SSTRL(TAB_JESCAPE));
			o += SSTRL(TAB_JESCAPE);
			break;
		case '\n':
			// cppcheck-suppress invalidFunctionArg
			memcpy(o, NEWLINE_JESCAPE, SSTRL(NEWLINE_JESCAPE));
			o += SSTRL(NEWLINE_JESCAPE);
			break;
		default:
			// Escape control characters.
			if ((c < 0x20) || (c == 0x7f)) {
				snprintf(o, 7, "\\u%04x", c);
				o += 6;
			}
			else {
				*o++ = c;
			}
			break;
		}
	}
	// null terminator
	*o = '\0';
}

std::ostream& operator<<(std::ostream& out, const json_stream_escaper& e)
{
  boost::optional<hex_formatter> fmt;

  for (unsigned char c : e.str) {
    switch (c) {
    case '"':
      out << DBL_QUOTE_JESCAPE;
      break;
    case '\\':
      out << BACKSLASH_JESCAPE;
      break;
    case '\t':
      out << TAB_JESCAPE;
      break;
    case '\n':
      out << NEWLINE_JESCAPE;
      break;
    default:
      // Escape control characters.
      if ((c < 0x20) || (c == 0x7f)) {
        if (!fmt) {
          fmt.emplace(out); // enable hex formatting
        }
        out << "\\u" << std::setw(4) << static_cast<unsigned int>(c);
      } else {
        out << c;
      }
      break;
    }
  }
  return out;
}