net/http/http

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
FindStringEnd
FindDelimiter
ParseContentType
ParseRanges
ParseRangeHeader
HasHeader
IsSafeHeader
StripHeaders
IsNonCoalescingHeader
IsLWS
TrimLWS
IsQuote
IsToken
Unquote
Unquote
Quote
LocateStartOfStatusLine
LocateEndOfHeaders
IsLineSegmentContinuable
FindStatusLineEnd
FindFirstNonLWS
AssembleRawHeaders
ConvertHeadersBackToHTTPResponse
GenerateAcceptLanguageHeader
AppendHeaderIfMissing
HasStrongValidators
GetStatusCodesForHistogram
MapStatusCodeForHistogram
GetNext
AdvanceTo
GetNext
value_is_quoted_
GetNext
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// The rules for parsing content-types were borrowed from Firefox:
// http://lxr.mozilla.org/mozilla/source/netwerk/base/src/nsURLHelper.cpp#834

#include "net/http/http_util.h"

#include <algorithm>

#include "base/basictypes.h"
#include "base/logging.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_piece.h"
#include "base/strings/string_tokenizer.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
#include "base/time/time.h"


namespace net {

// Helpers --------------------------------------------------------------------

// Returns the index of the closing quote of the string, if any.  |start| points
// at the opening quote.
static size_t FindStringEnd(const std::string& line, size_t start, char delim) {
  DCHECK_LT(start, line.length());
  DCHECK_EQ(line[start], delim);
  DCHECK((delim == '"') || (delim == '\''));

  const char set[] = { delim, '\\', '\0' };
  for (size_t end = line.find_first_of(set, start + 1);
       end != std::string::npos; end = line.find_first_of(set, end + 2)) {
    if (line[end] != '\\')
      return end;
  }
  return line.length();
}


// HttpUtil -------------------------------------------------------------------

// static
size_t HttpUtil::FindDelimiter(const std::string& line,
                               size_t search_start,
                               char delimiter) {
  do {
    // search_start points to the spot from which we should start looking
    // for the delimiter.
    const char delim_str[] = { delimiter, '"', '\'', '\0' };
    size_t cur_delim_pos = line.find_first_of(delim_str, search_start);
    if (cur_delim_pos == std::string::npos)
      return line.length();

    char ch = line[cur_delim_pos];
    if (ch == delimiter) {
      // Found delimiter
      return cur_delim_pos;
    }

    // We hit the start of a quoted string.  Look for its end.
    search_start = FindStringEnd(line, cur_delim_pos, ch);
    if (search_start == line.length())
      return search_start;

    ++search_start;

    // search_start now points to the first char after the end of the
    // string, so just go back to the top of the loop and look for
    // |delimiter| again.
  } while (true);

  NOTREACHED();
  return line.length();
}

// static
void HttpUtil::ParseContentType(const std::string& content_type_str,
                                std::string* mime_type,
                                std::string* charset,
                                bool* had_charset,
                                std::string* boundary) {
  const std::string::const_iterator begin = content_type_str.begin();

  // Trim leading and trailing whitespace from type.  We include '(' in
  // the trailing trim set to catch media-type comments, which are not at all
  // standard, but may occur in rare cases.
  size_t type_val = content_type_str.find_first_not_of(HTTP_LWS);
  type_val = std::min(type_val, content_type_str.length());
  size_t type_end = content_type_str.find_first_of(HTTP_LWS ";(", type_val);
  if (type_end == std::string::npos)
    type_end = content_type_str.length();

  size_t charset_val = 0;
  size_t charset_end = 0;
  bool type_has_charset = false;

  // Iterate over parameters
  size_t param_start = content_type_str.find_first_of(';', type_end);
  if (param_start != std::string::npos) {
    base::StringTokenizer tokenizer(begin + param_start, content_type_str.end(),
                                    ";");
    tokenizer.set_quote_chars("\"");
    while (tokenizer.GetNext()) {
      std::string::const_iterator equals_sign =
          std::find(tokenizer.token_begin(), tokenizer.token_end(), '=');
      if (equals_sign == tokenizer.token_end())
        continue;

      std::string::const_iterator param_name_begin = tokenizer.token_begin();
      std::string::const_iterator param_name_end = equals_sign;
      TrimLWS(&param_name_begin, &param_name_end);

      std::string::const_iterator param_value_begin = equals_sign + 1;
      std::string::const_iterator param_value_end = tokenizer.token_end();
      DCHECK(param_value_begin <= tokenizer.token_end());
      TrimLWS(&param_value_begin, &param_value_end);

      if (LowerCaseEqualsASCII(param_name_begin, param_name_end, "charset")) {
        // TODO(abarth): Refactor this function to consistently use iterators.
        charset_val = param_value_begin - begin;
        charset_end = param_value_end - begin;
        type_has_charset = true;
      } else if (LowerCaseEqualsASCII(param_name_begin, param_name_end,
                                      "boundary")) {
        if (boundary)
          boundary->assign(param_value_begin, param_value_end);
      }
    }
  }

  if (type_has_charset) {
    // Trim leading and trailing whitespace from charset_val.  We include
    // '(' in the trailing trim set to catch media-type comments, which are
    // not at all standard, but may occur in rare cases.
    charset_val = content_type_str.find_first_not_of(HTTP_LWS, charset_val);
    charset_val = std::min(charset_val, charset_end);
    char first_char = content_type_str[charset_val];
    if (first_char == '"' || first_char == '\'') {
      charset_end = FindStringEnd(content_type_str, charset_val, first_char);
      ++charset_val;
      DCHECK(charset_end >= charset_val);
    } else {
      charset_end = std::min(content_type_str.find_first_of(HTTP_LWS ";(",
                                                            charset_val),
                             charset_end);
    }
  }

  // if the server sent "*/*", it is meaningless, so do not store it.
  // also, if type_val is the same as mime_type, then just update the
  // charset.  however, if charset is empty and mime_type hasn't
  // changed, then don't wipe-out an existing charset.  We
  // also want to reject a mime-type if it does not include a slash.
  // some servers give junk after the charset parameter, which may
  // include a comma, so this check makes us a bit more tolerant.
  if (content_type_str.length() != 0 &&
      content_type_str != "*/*" &&
      content_type_str.find_first_of('/') != std::string::npos) {
    // Common case here is that mime_type is empty
    bool eq = !mime_type->empty() && LowerCaseEqualsASCII(begin + type_val,
                                                          begin + type_end,
                                                          mime_type->data());
    if (!eq) {
      mime_type->assign(begin + type_val, begin + type_end);
      StringToLowerASCII(mime_type);
    }
    if ((!eq && *had_charset) || type_has_charset) {
      *had_charset = true;
      charset->assign(begin + charset_val, begin + charset_end);
      StringToLowerASCII(charset);
    }
  }
}

// static
// Parse the Range header according to RFC 2616 14.35.1
// ranges-specifier = byte-ranges-specifier
// byte-ranges-specifier = bytes-unit "=" byte-range-set
// byte-range-set  = 1#( byte-range-spec | suffix-byte-range-spec )
// byte-range-spec = first-byte-pos "-" [last-byte-pos]
// first-byte-pos  = 1*DIGIT
// last-byte-pos   = 1*DIGIT
bool HttpUtil::ParseRanges(const std::string& headers,
                           std::vector<HttpByteRange>* ranges) {
  std::string ranges_specifier;
  HttpUtil::HeadersIterator it(headers.begin(), headers.end(), "\r\n");

  while (it.GetNext()) {
    // Look for "Range" header.
    if (!LowerCaseEqualsASCII(it.name(), "range"))
      continue;
    ranges_specifier = it.values();
    // We just care about the first "Range" header, so break here.
    break;
  }

  if (ranges_specifier.empty())
    return false;

  return ParseRangeHeader(ranges_specifier, ranges);
}

// static
bool HttpUtil::ParseRangeHeader(const std::string& ranges_specifier,
                                std::vector<HttpByteRange>* ranges) {
  size_t equal_char_offset = ranges_specifier.find('=');
  if (equal_char_offset == std::string::npos)
    return false;

  // Try to extract bytes-unit part.
  std::string::const_iterator bytes_unit_begin = ranges_specifier.begin();
  std::string::const_iterator bytes_unit_end = bytes_unit_begin +
                                               equal_char_offset;
  std::string::const_iterator byte_range_set_begin = bytes_unit_end + 1;
  std::string::const_iterator byte_range_set_end = ranges_specifier.end();

  TrimLWS(&bytes_unit_begin, &bytes_unit_end);
  // "bytes" unit identifier is not found.
  if (!LowerCaseEqualsASCII(bytes_unit_begin, bytes_unit_end, "bytes"))
    return false;

  ValuesIterator byte_range_set_iterator(byte_range_set_begin,
                                         byte_range_set_end, ',');
  while (byte_range_set_iterator.GetNext()) {
    size_t minus_char_offset = byte_range_set_iterator.value().find('-');
    // If '-' character is not found, reports failure.
    if (minus_char_offset == std::string::npos)
      return false;

    std::string::const_iterator first_byte_pos_begin =
        byte_range_set_iterator.value_begin();
    std::string::const_iterator first_byte_pos_end =
        first_byte_pos_begin +  minus_char_offset;
    TrimLWS(&first_byte_pos_begin, &first_byte_pos_end);
    std::string first_byte_pos(first_byte_pos_begin, first_byte_pos_end);

    HttpByteRange range;
    // Try to obtain first-byte-pos.
    if (!first_byte_pos.empty()) {
      int64 first_byte_position = -1;
      if (!base::StringToInt64(first_byte_pos, &first_byte_position))
        return false;
      range.set_first_byte_position(first_byte_position);
    }

    std::string::const_iterator last_byte_pos_begin =
        byte_range_set_iterator.value_begin() + minus_char_offset + 1;
    std::string::const_iterator last_byte_pos_end =
        byte_range_set_iterator.value_end();
    TrimLWS(&last_byte_pos_begin, &last_byte_pos_end);
    std::string last_byte_pos(last_byte_pos_begin, last_byte_pos_end);

    // We have last-byte-pos or suffix-byte-range-spec in this case.
    if (!last_byte_pos.empty()) {
      int64 last_byte_position;
      if (!base::StringToInt64(last_byte_pos, &last_byte_position))
        return false;
      if (range.HasFirstBytePosition())
        range.set_last_byte_position(last_byte_position);
      else
        range.set_suffix_length(last_byte_position);
    } else if (!range.HasFirstBytePosition()) {
      return false;
    }

    // Do a final check on the HttpByteRange object.
    if (!range.IsValid())
      return false;
    ranges->push_back(range);
  }
  return !ranges->empty();
}

// static
bool HttpUtil::HasHeader(const std::string& headers, const char* name) {
  size_t name_len = strlen(name);
  std::string::const_iterator it =
      std::search(headers.begin(),
                  headers.end(),
                  name,
                  name + name_len,
                  base::CaseInsensitiveCompareASCII<char>());
  if (it == headers.end())
    return false;

  // ensure match is prefixed by newline
  if (it != headers.begin() && it[-1] != '\n')
    return false;

  // ensure match is suffixed by colon
  if (it + name_len >= headers.end() || it[name_len] != ':')
    return false;

  return true;
}

namespace {
// A header string containing any of the following fields will cause
// an error. The list comes from the XMLHttpRequest standard.
// http://www.w3.org/TR/XMLHttpRequest/#the-setrequestheader-method
const char* const kForbiddenHeaderFields[] = {
  "accept-charset",
  "accept-encoding",
  "access-control-request-headers",
  "access-control-request-method",
  "connection",
  "content-length",
  "cookie",
  "cookie2",
  "content-transfer-encoding",
  "date",
  "expect",
  "host",
  "keep-alive",
  "origin",
  "referer",
  "te",
  "trailer",
  "transfer-encoding",
  "upgrade",
  "user-agent",
  "via",
};
}  // anonymous namespace

// static
bool HttpUtil::IsSafeHeader(const std::string& name) {
  std::string lower_name(StringToLowerASCII(name));
  if (StartsWithASCII(lower_name, "proxy-", true) ||
      StartsWithASCII(lower_name, "sec-", true))
    return false;
  for (size_t i = 0; i < arraysize(kForbiddenHeaderFields); ++i) {
    if (lower_name == kForbiddenHeaderFields[i])
      return false;
  }
  return true;
}

// static
std::string HttpUtil::StripHeaders(const std::string& headers,
                                   const char* const headers_to_remove[],
                                   size_t headers_to_remove_len) {
  std::string stripped_headers;
  net::HttpUtil::HeadersIterator it(headers.begin(), headers.end(), "\r\n");

  while (it.GetNext()) {
    bool should_remove = false;
    for (size_t i = 0; i < headers_to_remove_len; ++i) {
      if (LowerCaseEqualsASCII(it.name_begin(), it.name_end(),
                               headers_to_remove[i])) {
        should_remove = true;
        break;
      }
    }
    if (!should_remove) {
      // Assume that name and values are on the same line.
      stripped_headers.append(it.name_begin(), it.values_end());
      stripped_headers.append("\r\n");
    }
  }
  return stripped_headers;
}

// static
bool HttpUtil::IsNonCoalescingHeader(std::string::const_iterator name_begin,
                                     std::string::const_iterator name_end) {
  // NOTE: "set-cookie2" headers do not support expires attributes, so we don't
  // have to list them here.
  const char* kNonCoalescingHeaders[] = {
    "date",
    "expires",
    "last-modified",
    "location",  // See bug 1050541 for details
    "retry-after",
    "set-cookie",
    // The format of auth-challenges mixes both space separated tokens and
    // comma separated properties, so coalescing on comma won't work.
    "www-authenticate",
    "proxy-authenticate",
    // STS specifies that UAs must not process any STS headers after the first
    // one.
    "strict-transport-security"
  };
  for (size_t i = 0; i < arraysize(kNonCoalescingHeaders); ++i) {
    if (LowerCaseEqualsASCII(name_begin, name_end, kNonCoalescingHeaders[i]))
      return true;
  }
  return false;
}

bool HttpUtil::IsLWS(char c) {
  return strchr(HTTP_LWS, c) != NULL;
}

void HttpUtil::TrimLWS(std::string::const_iterator* begin,
                       std::string::const_iterator* end) {
  // leading whitespace
  while (*begin < *end && IsLWS((*begin)[0]))
    ++(*begin);

  // trailing whitespace
  while (*begin < *end && IsLWS((*end)[-1]))
    --(*end);
}

bool HttpUtil::IsQuote(char c) {
  // Single quote mark isn't actually part of quoted-text production,
  // but apparently some servers rely on this.
  return c == '"' || c == '\'';
}

// See RFC 2616 Sec 2.2 for the definition of |token|.
bool HttpUtil::IsToken(std::string::const_iterator begin,
                       std::string::const_iterator end) {
  if (begin == end)
    return false;
  for (std::string::const_iterator iter = begin; iter != end; ++iter) {
    unsigned char c = *iter;
    if (c >= 0x80 || c <= 0x1F || c == 0x7F ||
        c == '(' || c == ')' || c == '<' || c == '>' || c == '@' ||
        c == ',' || c == ';' || c == ':' || c == '\\' || c == '"' ||
        c == '/' || c == '[' || c == ']' || c == '?' || c == '=' ||
        c == '{' || c == '}' || c == ' ' || c == '\t')
      return false;
  }
  return true;
}

std::string HttpUtil::Unquote(std::string::const_iterator begin,
                              std::string::const_iterator end) {
  // Empty string
  if (begin == end)
    return std::string();

  // Nothing to unquote.
  if (!IsQuote(*begin))
    return std::string(begin, end);

  // No terminal quote mark.
  if (end - begin < 2 || *begin != *(end - 1))
    return std::string(begin, end);

  // Strip quotemarks
  ++begin;
  --end;

  // Unescape quoted-pair (defined in RFC 2616 section 2.2)
  std::string unescaped;
  bool prev_escape = false;
  for (; begin != end; ++begin) {
    char c = *begin;
    if (c == '\\' && !prev_escape) {
      prev_escape = true;
      continue;
    }
    prev_escape = false;
    unescaped.push_back(c);
  }
  return unescaped;
}

// static
std::string HttpUtil::Unquote(const std::string& str) {
  return Unquote(str.begin(), str.end());
}

// static
std::string HttpUtil::Quote(const std::string& str) {
  std::string escaped;
  escaped.reserve(2 + str.size());

  std::string::const_iterator begin = str.begin();
  std::string::const_iterator end = str.end();

  // Esape any backslashes or quotemarks within the string, and
  // then surround with quotes.
  escaped.push_back('"');
  for (; begin != end; ++begin) {
    char c = *begin;
    if (c == '"' || c == '\\')
      escaped.push_back('\\');
    escaped.push_back(c);
  }
  escaped.push_back('"');
  return escaped;
}

// Find the "http" substring in a status line. This allows for
// some slop at the start. If the "http" string could not be found
// then returns -1.
// static
int HttpUtil::LocateStartOfStatusLine(const char* buf, int buf_len) {
  const int slop = 4;
  const int http_len = 4;

  if (buf_len >= http_len) {
    int i_max = std::min(buf_len - http_len, slop);
    for (int i = 0; i <= i_max; ++i) {
      if (LowerCaseEqualsASCII(buf + i, buf + i + http_len, "http"))
        return i;
    }
  }
  return -1;  // Not found
}

int HttpUtil::LocateEndOfHeaders(const char* buf, int buf_len, int i) {
  bool was_lf = false;
  char last_c = '\0';
  for (; i < buf_len; ++i) {
    char c = buf[i];
    if (c == '\n') {
      if (was_lf)
        return i + 1;
      was_lf = true;
    } else if (c != '\r' || last_c != '\n') {
      was_lf = false;
    }
    last_c = c;
  }
  return -1;
}

// In order for a line to be continuable, it must specify a
// non-blank header-name. Line continuations are specifically for
// header values -- do not allow headers names to span lines.
static bool IsLineSegmentContinuable(const char* begin, const char* end) {
  if (begin == end)
    return false;

  const char* colon = std::find(begin, end, ':');
  if (colon == end)
    return false;

  const char* name_begin = begin;
  const char* name_end = colon;

  // Name can't be empty.
  if (name_begin == name_end)
    return false;

  // Can't start with LWS (this would imply the segment is a continuation)
  if (HttpUtil::IsLWS(*name_begin))
    return false;

  return true;
}

// Helper used by AssembleRawHeaders, to find the end of the status line.
static const char* FindStatusLineEnd(const char* begin, const char* end) {
  size_t i = base::StringPiece(begin, end - begin).find_first_of("\r\n");
  if (i == base::StringPiece::npos)
    return end;
  return begin + i;
}

// Helper used by AssembleRawHeaders, to skip past leading LWS.
static const char* FindFirstNonLWS(const char* begin, const char* end) {
  for (const char* cur = begin; cur != end; ++cur) {
    if (!HttpUtil::IsLWS(*cur))
      return cur;
  }
  return end;  // Not found.
}

std::string HttpUtil::AssembleRawHeaders(const char* input_begin,
                                         int input_len) {
  std::string raw_headers;
  raw_headers.reserve(input_len);

  const char* input_end = input_begin + input_len;

  // Skip any leading slop, since the consumers of this output
  // (HttpResponseHeaders) don't deal with it.
  int status_begin_offset = LocateStartOfStatusLine(input_begin, input_len);
  if (status_begin_offset != -1)
    input_begin += status_begin_offset;

  // Copy the status line.
  const char* status_line_end = FindStatusLineEnd(input_begin, input_end);
  raw_headers.append(input_begin, status_line_end);

  // After the status line, every subsequent line is a header line segment.
  // Should a segment start with LWS, it is a continuation of the previous
  // line's field-value.

  // TODO(ericroman): is this too permissive? (delimits on [\r\n]+)
  base::CStringTokenizer lines(status_line_end, input_end, "\r\n");

  // This variable is true when the previous line was continuable.
  bool prev_line_continuable = false;

  while (lines.GetNext()) {
    const char* line_begin = lines.token_begin();
    const char* line_end = lines.token_end();

    if (prev_line_continuable && IsLWS(*line_begin)) {
      // Join continuation; reduce the leading LWS to a single SP.
      raw_headers.push_back(' ');
      raw_headers.append(FindFirstNonLWS(line_begin, line_end), line_end);
    } else {
      // Terminate the previous line.
      raw_headers.push_back('\n');

      // Copy the raw data to output.
      raw_headers.append(line_begin, line_end);

      // Check if the current line can be continued.
      prev_line_continuable = IsLineSegmentContinuable(line_begin, line_end);
    }
  }

  raw_headers.append("\n\n", 2);

  // Use '\0' as the canonical line terminator. If the input already contained
  // any embeded '\0' characters we will strip them first to avoid interpreting
  // them as line breaks.
  raw_headers.erase(std::remove(raw_headers.begin(), raw_headers.end(), '\0'),
                    raw_headers.end());
  std::replace(raw_headers.begin(), raw_headers.end(), '\n', '\0');

  return raw_headers;
}

std::string HttpUtil::ConvertHeadersBackToHTTPResponse(const std::string& str) {
  std::string disassembled_headers;
  base::StringTokenizer tokenizer(str, std::string(1, '\0'));
  while (tokenizer.GetNext()) {
    disassembled_headers.append(tokenizer.token_begin(), tokenizer.token_end());
    disassembled_headers.append("\r\n");
  }
  disassembled_headers.append("\r\n");

  return disassembled_headers;
}

// TODO(jungshik): 1. If the list is 'fr-CA,fr-FR,en,de', we have to add
// 'fr' after 'fr-CA' with the same q-value as 'fr-CA' because
// web servers, in general, do not fall back to 'fr' and may end up picking
// 'en' which has a lower preference than 'fr-CA' and 'fr-FR'.
// 2. This function assumes that the input is a comma separated list
// without any whitespace. As long as it comes from the preference and
// a user does not manually edit the preference file, it's the case. Still,
// we may have to make it more robust.
std::string HttpUtil::GenerateAcceptLanguageHeader(
    const std::string& raw_language_list) {
  // We use integers for qvalue and qvalue decrement that are 10 times
  // larger than actual values to avoid a problem with comparing
  // two floating point numbers.
  const unsigned int kQvalueDecrement10 = 2;
  unsigned int qvalue10 = 10;
  base::StringTokenizer t(raw_language_list, ",");
  std::string lang_list_with_q;
  while (t.GetNext()) {
    std::string language = t.token();
    if (qvalue10 == 10) {
      // q=1.0 is implicit.
      lang_list_with_q = language;
    } else {
      DCHECK_LT(qvalue10, 10U);
      base::StringAppendF(&lang_list_with_q, ",%s;q=0.%d", language.c_str(),
                          qvalue10);
    }
    // It does not make sense to have 'q=0'.
    if (qvalue10 > kQvalueDecrement10)
      qvalue10 -= kQvalueDecrement10;
  }
  return lang_list_with_q;
}

void HttpUtil::AppendHeaderIfMissing(const char* header_name,
                                     const std::string& header_value,
                                     std::string* headers) {
  if (header_value.empty())
    return;
  if (net::HttpUtil::HasHeader(*headers, header_name))
    return;
  *headers += std::string(header_name) + ": " + header_value + "\r\n";
}

bool HttpUtil::HasStrongValidators(HttpVersion version,
                                   const std::string& etag_header,
                                   const std::string& last_modified_header,
                                   const std::string& date_header) {
  if (version < HttpVersion(1, 1))
    return false;

  if (!etag_header.empty()) {
    size_t slash = etag_header.find('/');
    if (slash == std::string::npos || slash == 0)
      return true;

    std::string::const_iterator i = etag_header.begin();
    std::string::const_iterator j = etag_header.begin() + slash;
    TrimLWS(&i, &j);
    if (!LowerCaseEqualsASCII(i, j, "w"))
      return true;
  }

  base::Time last_modified;
  if (!base::Time::FromString(last_modified_header.c_str(), &last_modified))
    return false;

  base::Time date;
  if (!base::Time::FromString(date_header.c_str(), &date))
    return false;

  return ((date - last_modified).InSeconds() >= 60);
}

// Functions for histogram initialization.  The code 0 is put in the map to
// track status codes that are invalid.
// TODO(gavinp): Greatly prune the collected codes once we learn which
// ones are not sent in practice, to reduce upload size & memory use.

enum {
  HISTOGRAM_MIN_HTTP_STATUS_CODE = 100,
  HISTOGRAM_MAX_HTTP_STATUS_CODE = 599,
};

// static
std::vector<int> HttpUtil::GetStatusCodesForHistogram() {
  std::vector<int> codes;
  codes.reserve(
      HISTOGRAM_MAX_HTTP_STATUS_CODE - HISTOGRAM_MIN_HTTP_STATUS_CODE + 2);
  codes.push_back(0);
  for (int i = HISTOGRAM_MIN_HTTP_STATUS_CODE;
       i <= HISTOGRAM_MAX_HTTP_STATUS_CODE; ++i)
    codes.push_back(i);
  return codes;
}

// static
int HttpUtil::MapStatusCodeForHistogram(int code) {
  if (HISTOGRAM_MIN_HTTP_STATUS_CODE <= code &&
      code <= HISTOGRAM_MAX_HTTP_STATUS_CODE)
    return code;
  return 0;
}

// BNF from section 4.2 of RFC 2616:
//
//   message-header = field-name ":" [ field-value ]
//   field-name     = token
//   field-value    = *( field-content | LWS )
//   field-content  = <the OCTETs making up the field-value
//                     and consisting of either *TEXT or combinations
//                     of token, separators, and quoted-string>
//

HttpUtil::HeadersIterator::HeadersIterator(
    std::string::const_iterator headers_begin,
    std::string::const_iterator headers_end,
    const std::string& line_delimiter)
    : lines_(headers_begin, headers_end, line_delimiter) {
}

HttpUtil::HeadersIterator::~HeadersIterator() {
}

bool HttpUtil::HeadersIterator::GetNext() {
  while (lines_.GetNext()) {
    name_begin_ = lines_.token_begin();
    values_end_ = lines_.token_end();

    std::string::const_iterator colon(std::find(name_begin_, values_end_, ':'));
    if (colon == values_end_)
      continue;  // skip malformed header

    name_end_ = colon;

    // If the name starts with LWS, it is an invalid line.
    // Leading LWS implies a line continuation, and these should have
    // already been joined by AssembleRawHeaders().
    if (name_begin_ == name_end_ || IsLWS(*name_begin_))
      continue;

    TrimLWS(&name_begin_, &name_end_);
    if (name_begin_ == name_end_)
      continue;  // skip malformed header

    values_begin_ = colon + 1;
    TrimLWS(&values_begin_, &values_end_);

    // if we got a header name, then we are done.
    return true;
  }
  return false;
}

bool HttpUtil::HeadersIterator::AdvanceTo(const char* name) {
  DCHECK(name != NULL);
  DCHECK_EQ(0, StringToLowerASCII<std::string>(name).compare(name))
      << "the header name must be in all lower case";

  while (GetNext()) {
    if (LowerCaseEqualsASCII(name_begin_, name_end_, name)) {
      return true;
    }
  }

  return false;
}

HttpUtil::ValuesIterator::ValuesIterator(
    std::string::const_iterator values_begin,
    std::string::const_iterator values_end,
    char delimiter)
    : values_(values_begin, values_end, std::string(1, delimiter)) {
  values_.set_quote_chars("\'\"");
}

HttpUtil::ValuesIterator::~ValuesIterator() {
}

bool HttpUtil::ValuesIterator::GetNext() {
  while (values_.GetNext()) {
    value_begin_ = values_.token_begin();
    value_end_ = values_.token_end();
    TrimLWS(&value_begin_, &value_end_);

    // bypass empty values.
    if (value_begin_ != value_end_)
      return true;
  }
  return false;
}

HttpUtil::NameValuePairsIterator::NameValuePairsIterator(
    std::string::const_iterator begin,
    std::string::const_iterator end,
    char delimiter)
    : props_(begin, end, delimiter),
      valid_(true),
      name_begin_(end),
      name_end_(end),
      value_begin_(end),
      value_end_(end),
      value_is_quoted_(false) {
}

HttpUtil::NameValuePairsIterator::~NameValuePairsIterator() {}

// We expect properties to be formatted as one of:
//   name="value"
//   name='value'
//   name='\'value\''
//   name=value
//   name = value
//   name=
// Due to buggy implementations found in some embedded devices, we also
// accept values with missing close quotemark (http://crbug.com/39836):
//   name="value
bool HttpUtil::NameValuePairsIterator::GetNext() {
  if (!props_.GetNext())
    return false;

  // Set the value as everything. Next we will split out the name.
  value_begin_ = props_.value_begin();
  value_end_ = props_.value_end();
  name_begin_ = name_end_ = value_end_;

  // Scan for the equals sign.
  std::string::const_iterator equals = std::find(value_begin_, value_end_, '=');
  if (equals == value_end_ || equals == value_begin_)
    return valid_ = false;  // Malformed, no equals sign

  // Verify that the equals sign we found wasn't inside of quote marks.
  for (std::string::const_iterator it = value_begin_; it != equals; ++it) {
    if (HttpUtil::IsQuote(*it))
      return valid_ = false;  // Malformed, quote appears before equals sign
  }

  name_begin_ = value_begin_;
  name_end_ = equals;
  value_begin_ = equals + 1;

  TrimLWS(&name_begin_, &name_end_);
  TrimLWS(&value_begin_, &value_end_);
  value_is_quoted_ = false;
  unquoted_value_.clear();

  if (value_begin_ == value_end_)
    return valid_ = false;  // Malformed, value is empty

  if (HttpUtil::IsQuote(*value_begin_)) {
    // Trim surrounding quotemarks off the value
    if (*value_begin_ != *(value_end_ - 1) || value_begin_ + 1 == value_end_) {
      // NOTE: This is not as graceful as it sounds:
      // * quoted-pairs will no longer be unquoted
      //   (["\"hello] should give ["hello]).
      // * Does not detect when the final quote is escaped
      //   (["value\"] should give [value"])
      ++value_begin_;  // Gracefully recover from mismatching quotes.
    } else {
      value_is_quoted_ = true;
      // Do not store iterators into this. See declaration of unquoted_value_.
      unquoted_value_ = HttpUtil::Unquote(value_begin_, value_end_);
    }
  }

  return true;
}

}  // namespace net
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root/net/http/http_util.cc

DEFINITIONS
