net/base/mime

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
FindMimeType
GetMimeTypeFromExtension
GetWellKnownMimeTypeFromExtension
GetMimeTypeFromFile
GetMimeTypeFromExtensionHelper
IsCodecSupportedOnAndroid
AreSupportedCodecs
InitializeMimeTypeMaps
IsSupportedImageMimeType
IsSupportedMediaMimeType
IsSupportedNonImageMimeType
IsUnsupportedTextMimeType
IsSupportedJavascriptMimeType
IsSupportedMimeType
MatchesMimeTypeParameters
MatchesMimeType
IsMimeType
AreSupportedMediaCodecs
ParseCodecString
IsStrictMediaMimeType
IsSupportedStrictMediaMimeType
RemoveProprietaryMediaTypesAndCodecsForTests
GetMimeTypeFromExtension
GetMimeTypeFromFile
GetWellKnownMimeTypeFromExtension
GetPreferredExtensionForMimeType
IsSupportedImageMimeType
IsSupportedMediaMimeType
IsSupportedNonImageMimeType
IsUnsupportedTextMimeType
IsSupportedJavascriptMimeType
IsSupportedMimeType
MatchesMimeType
IsMimeType
AreSupportedMediaCodecs
IsStrictMediaMimeType
IsSupportedStrictMediaMimeType
ParseCodecString
GetExtensionsFromHardCodedMappings
GetExtensionsHelper
HashSetToVector
GetExtensionsForMimeType
RemoveProprietaryMediaTypesAndCodecsForTests
GetIANAMediaType
GetCertificateMimeTypeForMimeType
IsSupportedCertificateMimeType
AddMultipartValueForUpload
AddMultipartFinalDelimiterForUpload
// 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.

#include <algorithm>
#include <iterator>
#include <map>
#include <string>

#include "base/containers/hash_tables.h"
#include "base/lazy_instance.h"
#include "base/logging.h"
#include "base/stl_util.h"
#include "base/strings/string_split.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "net/base/mime_util.h"
#include "net/base/platform_mime_util.h"

#if defined(OS_ANDROID)
#include "base/android/build_info.h"
#endif

using std::string;

namespace {

struct MediaType {
  const char name[12];
  const char matcher[13];
};

static const MediaType kIanaMediaTypes[] = {
  { "application", "application/" },
  { "audio", "audio/" },
  { "example", "example/" },
  { "image", "image/" },
  { "message", "message/" },
  { "model", "model/" },
  { "multipart", "multipart/" },
  { "text", "text/" },
  { "video", "video/" },
};

}  // namespace

namespace net {

// Singleton utility class for mime types.
class MimeUtil : public PlatformMimeUtil {
 public:
  bool GetMimeTypeFromExtension(const base::FilePath::StringType& ext,
                                std::string* mime_type) const;

  bool GetMimeTypeFromFile(const base::FilePath& file_path,
                           std::string* mime_type) const;

  bool GetWellKnownMimeTypeFromExtension(const base::FilePath::StringType& ext,
                                         std::string* mime_type) const;

  bool IsSupportedImageMimeType(const std::string& mime_type) const;
  bool IsSupportedMediaMimeType(const std::string& mime_type) const;
  bool IsSupportedNonImageMimeType(const std::string& mime_type) const;
  bool IsUnsupportedTextMimeType(const std::string& mime_type) const;
  bool IsSupportedJavascriptMimeType(const std::string& mime_type) const;

  bool IsSupportedMimeType(const std::string& mime_type) const;

  bool MatchesMimeType(const std::string &mime_type_pattern,
                       const std::string &mime_type) const;

  bool IsMimeType(const std::string& type_string) const;

  bool AreSupportedMediaCodecs(const std::vector<std::string>& codecs) const;

  void ParseCodecString(const std::string& codecs,
                        std::vector<std::string>* codecs_out,
                        bool strip);

  bool IsStrictMediaMimeType(const std::string& mime_type) const;
  bool IsSupportedStrictMediaMimeType(
      const std::string& mime_type,
      const std::vector<std::string>& codecs) const;

  void RemoveProprietaryMediaTypesAndCodecsForTests();

 private:
  friend struct base::DefaultLazyInstanceTraits<MimeUtil>;

  typedef base::hash_set<std::string> MimeMappings;
  typedef std::map<std::string, MimeMappings> StrictMappings;

  MimeUtil();

  // Returns true if |codecs| is nonempty and all the items in it are present in
  // |supported_codecs|.
  static bool AreSupportedCodecs(const MimeMappings& supported_codecs,
                                 const std::vector<std::string>& codecs);

  // For faster lookup, keep hash sets.
  void InitializeMimeTypeMaps();

  bool GetMimeTypeFromExtensionHelper(const base::FilePath::StringType& ext,
                                      bool include_platform_types,
                                      std::string* mime_type) const;

  MimeMappings image_map_;
  MimeMappings media_map_;
  MimeMappings non_image_map_;
  MimeMappings unsupported_text_map_;
  MimeMappings javascript_map_;
  MimeMappings codecs_map_;

  StrictMappings strict_format_map_;
};  // class MimeUtil

// This variable is Leaky because we need to access it from WorkerPool threads.
static base::LazyInstance<MimeUtil>::Leaky g_mime_util =
    LAZY_INSTANCE_INITIALIZER;

struct MimeInfo {
  const char* mime_type;
  const char* extensions;  // comma separated list
};

static const MimeInfo primary_mappings[] = {
  { "text/html", "html,htm,shtml,shtm" },
  { "text/css", "css" },
  { "text/xml", "xml" },
  { "image/gif", "gif" },
  { "image/jpeg", "jpeg,jpg" },
  { "image/webp", "webp" },
  { "image/png", "png" },
  { "video/mp4", "mp4,m4v" },
  { "audio/x-m4a", "m4a" },
  { "audio/mp3", "mp3" },
  { "video/ogg", "ogv,ogm" },
  { "audio/ogg", "ogg,oga,opus" },
  { "video/webm", "webm" },
  { "audio/webm", "webm" },
  { "audio/wav", "wav" },
  { "application/xhtml+xml", "xhtml,xht,xhtm" },
  { "application/x-chrome-extension", "crx" },
  { "multipart/related", "mhtml,mht" }
};

static const MimeInfo secondary_mappings[] = {
  { "application/octet-stream", "exe,com,bin" },
  { "application/gzip", "gz" },
  { "application/pdf", "pdf" },
  { "application/postscript", "ps,eps,ai" },
  { "application/javascript", "js" },
  { "application/font-woff", "woff" },
  { "image/bmp", "bmp" },
  { "image/x-icon", "ico" },
  { "image/vnd.microsoft.icon", "ico" },
  { "image/jpeg", "jfif,pjpeg,pjp" },
  { "image/tiff", "tiff,tif" },
  { "image/x-xbitmap", "xbm" },
  { "image/svg+xml", "svg,svgz" },
  { "message/rfc822", "eml" },
  { "text/plain", "txt,text" },
  { "text/html", "ehtml" },
  { "application/rss+xml", "rss" },
  { "application/rdf+xml", "rdf" },
  { "text/xml", "xsl,xbl,xslt" },
  { "application/vnd.mozilla.xul+xml", "xul" },
  { "application/x-shockwave-flash", "swf,swl" },
  { "application/pkcs7-mime", "p7m,p7c,p7z" },
  { "application/pkcs7-signature", "p7s" }
};

static const char* FindMimeType(const MimeInfo* mappings,
                                size_t mappings_len,
                                const char* ext) {
  size_t ext_len = strlen(ext);

  for (size_t i = 0; i < mappings_len; ++i) {
    const char* extensions = mappings[i].extensions;
    for (;;) {
      size_t end_pos = strcspn(extensions, ",");
      if (end_pos == ext_len &&
          base::strncasecmp(extensions, ext, ext_len) == 0)
        return mappings[i].mime_type;
      extensions += end_pos;
      if (!*extensions)
        break;
      extensions += 1;  // skip over comma
    }
  }
  return NULL;
}

bool MimeUtil::GetMimeTypeFromExtension(const base::FilePath::StringType& ext,
                                        string* result) const {
  return GetMimeTypeFromExtensionHelper(ext, true, result);
}

bool MimeUtil::GetWellKnownMimeTypeFromExtension(
    const base::FilePath::StringType& ext,
    string* result) const {
  return GetMimeTypeFromExtensionHelper(ext, false, result);
}

bool MimeUtil::GetMimeTypeFromFile(const base::FilePath& file_path,
                                   string* result) const {
  base::FilePath::StringType file_name_str = file_path.Extension();
  if (file_name_str.empty())
    return false;
  return GetMimeTypeFromExtension(file_name_str.substr(1), result);
}

bool MimeUtil::GetMimeTypeFromExtensionHelper(
    const base::FilePath::StringType& ext,
    bool include_platform_types,
    string* result) const {
  // Avoids crash when unable to handle a long file path. See crbug.com/48733.
  const unsigned kMaxFilePathSize = 65536;
  if (ext.length() > kMaxFilePathSize)
    return false;

  // We implement the same algorithm as Mozilla for mapping a file extension to
  // a mime type.  That is, we first check a hard-coded list (that cannot be
  // overridden), and then if not found there, we defer to the system registry.
  // Finally, we scan a secondary hard-coded list to catch types that we can
  // deduce but that we also want to allow the OS to override.

  base::FilePath path_ext(ext);
  const string ext_narrow_str = path_ext.AsUTF8Unsafe();
  const char* mime_type = FindMimeType(primary_mappings,
                                       arraysize(primary_mappings),
                                       ext_narrow_str.c_str());
  if (mime_type) {
    *result = mime_type;
    return true;
  }

  if (include_platform_types && GetPlatformMimeTypeFromExtension(ext, result))
    return true;

  mime_type = FindMimeType(secondary_mappings, arraysize(secondary_mappings),
                           ext_narrow_str.c_str());
  if (mime_type) {
    *result = mime_type;
    return true;
  }

  return false;
}

// From WebKit's WebCore/platform/MIMETypeRegistry.cpp:

static const char* const supported_image_types[] = {
  "image/jpeg",
  "image/pjpeg",
  "image/jpg",
  "image/webp",
  "image/png",
  "image/gif",
  "image/bmp",
  "image/vnd.microsoft.icon",    // ico
  "image/x-icon",    // ico
  "image/x-xbitmap"  // xbm
};

// A list of media types: http://en.wikipedia.org/wiki/Internet_media_type
// A comprehensive mime type list: http://plugindoc.mozdev.org/winmime.php
// This set of codecs is supported by all variations of Chromium.
static const char* const common_media_types[] = {
  // Ogg.
  "audio/ogg",
  "application/ogg",
#if !defined(OS_ANDROID)  // Android doesn't support Ogg Theora.
  "video/ogg",
#endif

  // WebM.
  "video/webm",
  "audio/webm",

  // Wav.
  "audio/wav",
  "audio/x-wav",

#if defined(OS_ANDROID)
  // HLS. Supported by Android ICS and above.
  "application/vnd.apple.mpegurl",
  "application/x-mpegurl",
#endif
};

// List of proprietary types only supported by Google Chrome.
static const char* const proprietary_media_types[] = {
  // MPEG-4.
  "video/mp4",
  "video/x-m4v",
  "audio/mp4",
  "audio/x-m4a",

  // MP3.
  "audio/mp3",
  "audio/x-mp3",
  "audio/mpeg",
};

// List of supported codecs when passed in with <source type="...">.
// This set of codecs is supported by all variations of Chromium.
//
// Refer to http://wiki.whatwg.org/wiki/Video_type_parameters#Browser_Support
// for more information.
//
// The codecs for WAV are integers as defined in Appendix A of RFC2361:
// http://tools.ietf.org/html/rfc2361
static const char* const common_media_codecs[] = {
#if !defined(OS_ANDROID)  // Android doesn't support Ogg Theora.
  "theora",
#endif
  "opus",
  "vorbis",
  "vp8",
  "vp9",
  "1"  // WAVE_FORMAT_PCM.
};

// List of proprietary codecs only supported by Google Chrome.
static const char* const proprietary_media_codecs[] = {
  "avc1",
  "avc3",
  "mp4a"
};

// Note:
// - does not include javascript types list (see supported_javascript_types)
// - does not include types starting with "text/" (see
//   IsSupportedNonImageMimeType())
static const char* const supported_non_image_types[] = {
  "image/svg+xml",  // SVG is text-based XML, even though it has an image/ type
  "application/xml",
  "application/atom+xml",
  "application/rss+xml",
  "application/xhtml+xml",
  "application/json",
  "multipart/related",  // For MHTML support.
  "multipart/x-mixed-replace"
  // Note: ADDING a new type here will probably render it AS HTML. This can
  // result in cross site scripting.
};

// Dictionary of cryptographic file mime types.
struct CertificateMimeTypeInfo {
  const char* mime_type;
  CertificateMimeType cert_type;
};

static const CertificateMimeTypeInfo supported_certificate_types[] = {
  { "application/x-x509-user-cert",
      CERTIFICATE_MIME_TYPE_X509_USER_CERT },
#if defined(OS_ANDROID)
  { "application/x-x509-ca-cert", CERTIFICATE_MIME_TYPE_X509_CA_CERT },
  { "application/x-pkcs12", CERTIFICATE_MIME_TYPE_PKCS12_ARCHIVE },
#endif
};

// These types are excluded from the logic that allows all text/ types because
// while they are technically text, it's very unlikely that a user expects to
// see them rendered in text form.
static const char* const unsupported_text_types[] = {
  "text/calendar",
  "text/x-calendar",
  "text/x-vcalendar",
  "text/vcalendar",
  "text/vcard",
  "text/x-vcard",
  "text/directory",
  "text/ldif",
  "text/qif",
  "text/x-qif",
  "text/x-csv",
  "text/x-vcf",
  "text/rtf",
  "text/comma-separated-values",
  "text/csv",
  "text/tab-separated-values",
  "text/tsv",
  "text/ofx",                           // http://crbug.com/162238
  "text/vnd.sun.j2me.app-descriptor"    // http://crbug.com/176450
};

//  Mozilla 1.8 and WinIE 7 both accept text/javascript and text/ecmascript.
//  Mozilla 1.8 accepts application/javascript, application/ecmascript, and
// application/x-javascript, but WinIE 7 doesn't.
//  WinIE 7 accepts text/javascript1.1 - text/javascript1.3, text/jscript, and
// text/livescript, but Mozilla 1.8 doesn't.
//  Mozilla 1.8 allows leading and trailing whitespace, but WinIE 7 doesn't.
//  Mozilla 1.8 and WinIE 7 both accept the empty string, but neither accept a
// whitespace-only string.
//  We want to accept all the values that either of these browsers accept, but
// not other values.
static const char* const supported_javascript_types[] = {
  "text/javascript",
  "text/ecmascript",
  "application/javascript",
  "application/ecmascript",
  "application/x-javascript",
  "text/javascript1.1",
  "text/javascript1.2",
  "text/javascript1.3",
  "text/jscript",
  "text/livescript"
};

#if defined(OS_ANDROID)
static bool IsCodecSupportedOnAndroid(const std::string& codec) {
  // VP9 is supported only in KitKat+ (API Level 19).
  if ((!codec.compare("vp9") || !codec.compare("vp9.0")) &&
      base::android::BuildInfo::GetInstance()->sdk_int() < 19) {
    return false;
  }

  // TODO(vigneshv): Change this similar to the VP9 check once Opus is
  // supported on Android (http://crbug.com/318436).
  if (!codec.compare("opus")) {
    return false;
  }
  return true;
}
#endif

struct MediaFormatStrict {
  const char* mime_type;
  const char* codecs_list;
};

static const MediaFormatStrict format_codec_mappings[] = {
  { "video/webm", "opus,vorbis,vp8,vp8.0,vp9,vp9.0" },
  { "audio/webm", "opus,vorbis" },
  { "audio/wav", "1" }
};

MimeUtil::MimeUtil() {
  InitializeMimeTypeMaps();
}

// static
bool MimeUtil::AreSupportedCodecs(const MimeMappings& supported_codecs,
                                  const std::vector<std::string>& codecs) {
  for (size_t i = 0; i < codecs.size(); ++i) {
    if (supported_codecs.find(codecs[i]) == supported_codecs.end())
      return false;
  }
  return !codecs.empty();
}

void MimeUtil::InitializeMimeTypeMaps() {
  for (size_t i = 0; i < arraysize(supported_image_types); ++i)
    image_map_.insert(supported_image_types[i]);

  // Initialize the supported non-image types.
  for (size_t i = 0; i < arraysize(supported_non_image_types); ++i)
    non_image_map_.insert(supported_non_image_types[i]);
  for (size_t i = 0; i < arraysize(supported_certificate_types); ++i)
    non_image_map_.insert(supported_certificate_types[i].mime_type);
  for (size_t i = 0; i < arraysize(unsupported_text_types); ++i)
    unsupported_text_map_.insert(unsupported_text_types[i]);
  for (size_t i = 0; i < arraysize(supported_javascript_types); ++i)
    non_image_map_.insert(supported_javascript_types[i]);
  for (size_t i = 0; i < arraysize(common_media_types); ++i)
    non_image_map_.insert(common_media_types[i]);
#if defined(USE_PROPRIETARY_CODECS)
  for (size_t i = 0; i < arraysize(proprietary_media_types); ++i)
    non_image_map_.insert(proprietary_media_types[i]);
#endif

  // Initialize the supported media types.
  for (size_t i = 0; i < arraysize(common_media_types); ++i)
    media_map_.insert(common_media_types[i]);
#if defined(USE_PROPRIETARY_CODECS)
  for (size_t i = 0; i < arraysize(proprietary_media_types); ++i)
    media_map_.insert(proprietary_media_types[i]);
#endif

  for (size_t i = 0; i < arraysize(supported_javascript_types); ++i)
    javascript_map_.insert(supported_javascript_types[i]);

  for (size_t i = 0; i < arraysize(common_media_codecs); ++i) {
#if defined(OS_ANDROID)
    if (!IsCodecSupportedOnAndroid(common_media_codecs[i]))
      continue;
#endif
    codecs_map_.insert(common_media_codecs[i]);
  }
#if defined(USE_PROPRIETARY_CODECS)
  for (size_t i = 0; i < arraysize(proprietary_media_codecs); ++i)
    codecs_map_.insert(proprietary_media_codecs[i]);
#endif

  // Initialize the strict supported media types.
  for (size_t i = 0; i < arraysize(format_codec_mappings); ++i) {
    std::vector<std::string> mime_type_codecs;
    ParseCodecString(format_codec_mappings[i].codecs_list,
                     &mime_type_codecs,
                     false);

    MimeMappings codecs;
    for (size_t j = 0; j < mime_type_codecs.size(); ++j) {
#if defined(OS_ANDROID)
      if (!IsCodecSupportedOnAndroid(mime_type_codecs[j]))
        continue;
#endif
      codecs.insert(mime_type_codecs[j]);
    }
    strict_format_map_[format_codec_mappings[i].mime_type] = codecs;
  }
}

bool MimeUtil::IsSupportedImageMimeType(const std::string& mime_type) const {
  return image_map_.find(mime_type) != image_map_.end();
}

bool MimeUtil::IsSupportedMediaMimeType(const std::string& mime_type) const {
  return media_map_.find(mime_type) != media_map_.end();
}

bool MimeUtil::IsSupportedNonImageMimeType(const std::string& mime_type) const {
  return non_image_map_.find(mime_type) != non_image_map_.end() ||
      (mime_type.compare(0, 5, "text/") == 0 &&
       !IsUnsupportedTextMimeType(mime_type)) ||
      (mime_type.compare(0, 12, "application/") == 0 &&
       MatchesMimeType("application/*+json", mime_type));
}

bool MimeUtil::IsUnsupportedTextMimeType(const std::string& mime_type) const {
  return unsupported_text_map_.find(mime_type) != unsupported_text_map_.end();
}

bool MimeUtil::IsSupportedJavascriptMimeType(
    const std::string& mime_type) const {
  return javascript_map_.find(mime_type) != javascript_map_.end();
}

// Mirrors WebViewImpl::CanShowMIMEType()
bool MimeUtil::IsSupportedMimeType(const std::string& mime_type) const {
  return (mime_type.compare(0, 6, "image/") == 0 &&
          IsSupportedImageMimeType(mime_type)) ||
         IsSupportedNonImageMimeType(mime_type);
}

// Tests for MIME parameter equality. Each parameter in the |mime_type_pattern|
// must be matched by a parameter in the |mime_type|. If there are no
// parameters in the pattern, the match is a success.
bool MatchesMimeTypeParameters(const std::string& mime_type_pattern,
                               const std::string& mime_type) {
  const std::string::size_type semicolon = mime_type_pattern.find(';');
  const std::string::size_type test_semicolon = mime_type.find(';');
  if (semicolon != std::string::npos) {
    if (test_semicolon == std::string::npos)
      return false;

    std::vector<std::string> pattern_parameters;
    base::SplitString(mime_type_pattern.substr(semicolon + 1),
                      ';', &pattern_parameters);

    std::vector<std::string> test_parameters;
    base::SplitString(mime_type.substr(test_semicolon + 1),
                      ';', &test_parameters);

    sort(pattern_parameters.begin(), pattern_parameters.end());
    sort(test_parameters.begin(), test_parameters.end());
    std::vector<std::string> difference =
      base::STLSetDifference<std::vector<std::string> >(pattern_parameters,
                                                        test_parameters);
    return difference.size() == 0;
  }
  return true;
}

// This comparison handles absolute maching and also basic
// wildcards.  The plugin mime types could be:
//      application/x-foo
//      application/*
//      application/*+xml
//      *
// Also tests mime parameters -- all parameters in the pattern must be present
// in the tested type for a match to succeed.
bool MimeUtil::MatchesMimeType(const std::string& mime_type_pattern,
                               const std::string& mime_type) const {
  // Verify caller is passing lowercase strings.
  DCHECK_EQ(StringToLowerASCII(mime_type_pattern), mime_type_pattern);
  DCHECK_EQ(StringToLowerASCII(mime_type), mime_type);

  if (mime_type_pattern.empty())
    return false;

  std::string::size_type semicolon = mime_type_pattern.find(';');
  const std::string base_pattern(mime_type_pattern.substr(0, semicolon));
  semicolon = mime_type.find(';');
  const std::string base_type(mime_type.substr(0, semicolon));

  if (base_pattern == "*" || base_pattern == "*/*")
    return MatchesMimeTypeParameters(mime_type_pattern, mime_type);

  const std::string::size_type star = base_pattern.find('*');
  if (star == std::string::npos) {
    if (base_pattern == base_type)
      return MatchesMimeTypeParameters(mime_type_pattern, mime_type);
    else
      return false;
  }

  // Test length to prevent overlap between |left| and |right|.
  if (base_type.length() < base_pattern.length() - 1)
    return false;

  const std::string left(base_pattern.substr(0, star));
  const std::string right(base_pattern.substr(star + 1));

  if (base_type.find(left) != 0)
    return false;

  if (!right.empty() &&
      base_type.rfind(right) != base_type.length() - right.length())
    return false;

  return MatchesMimeTypeParameters(mime_type_pattern, mime_type);
}

// See http://www.iana.org/assignments/media-types/index.html
static const char* legal_top_level_types[] = {
  "application/",
  "audio/",
  "example/",
  "image/",
  "message/",
  "model/",
  "multipart/",
  "text/",
  "video/",
};

bool MimeUtil::IsMimeType(const std::string& type_string) const {
  // MIME types are always ASCII and case-insensitive (at least, the top-level
  // and secondary types we care about).
  if (!IsStringASCII(type_string))
    return false;

  if (type_string == "*/*" || type_string == "*")
    return true;

  for (size_t i = 0; i < arraysize(legal_top_level_types); ++i) {
    if (StartsWithASCII(type_string, legal_top_level_types[i], false) &&
        type_string.length() > strlen(legal_top_level_types[i])) {
      return true;
    }
  }

  // If there's a "/" separator character, and the token before it is
  // "x-" + (ascii characters), it is also a MIME type.
  size_t slash = type_string.find('/');
  if (slash < 3 ||
      slash == std::string::npos || slash == type_string.length() - 1) {
    return false;
  }

  if (StartsWithASCII(type_string, "x-", false))
    return true;

  return false;
}

bool MimeUtil::AreSupportedMediaCodecs(
    const std::vector<std::string>& codecs) const {
  return AreSupportedCodecs(codecs_map_, codecs);
}

void MimeUtil::ParseCodecString(const std::string& codecs,
                                std::vector<std::string>* codecs_out,
                                bool strip) {
  std::string no_quote_codecs;
  base::TrimString(codecs, "\"", &no_quote_codecs);
  base::SplitString(no_quote_codecs, ',', codecs_out);

  if (!strip)
    return;

  // Strip everything past the first '.'
  for (std::vector<std::string>::iterator it = codecs_out->begin();
       it != codecs_out->end();
       ++it) {
    size_t found = it->find_first_of('.');
    if (found != std::string::npos)
      it->resize(found);
  }
}

bool MimeUtil::IsStrictMediaMimeType(const std::string& mime_type) const {
  if (strict_format_map_.find(mime_type) == strict_format_map_.end())
    return false;
  return true;
}

bool MimeUtil::IsSupportedStrictMediaMimeType(
    const std::string& mime_type,
    const std::vector<std::string>& codecs) const {
  StrictMappings::const_iterator it = strict_format_map_.find(mime_type);
  return (it != strict_format_map_.end()) &&
      AreSupportedCodecs(it->second, codecs);
}

void MimeUtil::RemoveProprietaryMediaTypesAndCodecsForTests() {
  for (size_t i = 0; i < arraysize(proprietary_media_types); ++i) {
    non_image_map_.erase(proprietary_media_types[i]);
    media_map_.erase(proprietary_media_types[i]);
  }
  for (size_t i = 0; i < arraysize(proprietary_media_codecs); ++i)
    codecs_map_.erase(proprietary_media_codecs[i]);
}

//----------------------------------------------------------------------------
// Wrappers for the singleton
//----------------------------------------------------------------------------

bool GetMimeTypeFromExtension(const base::FilePath::StringType& ext,
                              std::string* mime_type) {
  return g_mime_util.Get().GetMimeTypeFromExtension(ext, mime_type);
}

bool GetMimeTypeFromFile(const base::FilePath& file_path,
                         std::string* mime_type) {
  return g_mime_util.Get().GetMimeTypeFromFile(file_path, mime_type);
}

bool GetWellKnownMimeTypeFromExtension(const base::FilePath::StringType& ext,
                                       std::string* mime_type) {
  return g_mime_util.Get().GetWellKnownMimeTypeFromExtension(ext, mime_type);
}

bool GetPreferredExtensionForMimeType(const std::string& mime_type,
                                      base::FilePath::StringType* extension) {
  return g_mime_util.Get().GetPreferredExtensionForMimeType(mime_type,
                                                            extension);
}

bool IsSupportedImageMimeType(const std::string& mime_type) {
  return g_mime_util.Get().IsSupportedImageMimeType(mime_type);
}

bool IsSupportedMediaMimeType(const std::string& mime_type) {
  return g_mime_util.Get().IsSupportedMediaMimeType(mime_type);
}

bool IsSupportedNonImageMimeType(const std::string& mime_type) {
  return g_mime_util.Get().IsSupportedNonImageMimeType(mime_type);
}

bool IsUnsupportedTextMimeType(const std::string& mime_type) {
  return g_mime_util.Get().IsUnsupportedTextMimeType(mime_type);
}

bool IsSupportedJavascriptMimeType(const std::string& mime_type) {
  return g_mime_util.Get().IsSupportedJavascriptMimeType(mime_type);
}

bool IsSupportedMimeType(const std::string& mime_type) {
  return g_mime_util.Get().IsSupportedMimeType(mime_type);
}

bool MatchesMimeType(const std::string& mime_type_pattern,
                     const std::string& mime_type) {
  return g_mime_util.Get().MatchesMimeType(mime_type_pattern, mime_type);
}

bool IsMimeType(const std::string& type_string) {
  return g_mime_util.Get().IsMimeType(type_string);
}

bool AreSupportedMediaCodecs(const std::vector<std::string>& codecs) {
  return g_mime_util.Get().AreSupportedMediaCodecs(codecs);
}

bool IsStrictMediaMimeType(const std::string& mime_type) {
  return g_mime_util.Get().IsStrictMediaMimeType(mime_type);
}

bool IsSupportedStrictMediaMimeType(const std::string& mime_type,
                                    const std::vector<std::string>& codecs) {
  return g_mime_util.Get().IsSupportedStrictMediaMimeType(mime_type, codecs);
}

void ParseCodecString(const std::string& codecs,
                      std::vector<std::string>* codecs_out,
                      const bool strip) {
  g_mime_util.Get().ParseCodecString(codecs, codecs_out, strip);
}

namespace {

// From http://www.w3schools.com/media/media_mimeref.asp and
// http://plugindoc.mozdev.org/winmime.php
static const char* const kStandardImageTypes[] = {
  "image/bmp",
  "image/cis-cod",
  "image/gif",
  "image/ief",
  "image/jpeg",
  "image/webp",
  "image/pict",
  "image/pipeg",
  "image/png",
  "image/svg+xml",
  "image/tiff",
  "image/vnd.microsoft.icon",
  "image/x-cmu-raster",
  "image/x-cmx",
  "image/x-icon",
  "image/x-portable-anymap",
  "image/x-portable-bitmap",
  "image/x-portable-graymap",
  "image/x-portable-pixmap",
  "image/x-rgb",
  "image/x-xbitmap",
  "image/x-xpixmap",
  "image/x-xwindowdump"
};
static const char* const kStandardAudioTypes[] = {
  "audio/aac",
  "audio/aiff",
  "audio/amr",
  "audio/basic",
  "audio/midi",
  "audio/mp3",
  "audio/mp4",
  "audio/mpeg",
  "audio/mpeg3",
  "audio/ogg",
  "audio/vorbis",
  "audio/wav",
  "audio/webm",
  "audio/x-m4a",
  "audio/x-ms-wma",
  "audio/vnd.rn-realaudio",
  "audio/vnd.wave"
};
static const char* const kStandardVideoTypes[] = {
  "video/avi",
  "video/divx",
  "video/flc",
  "video/mp4",
  "video/mpeg",
  "video/ogg",
  "video/quicktime",
  "video/sd-video",
  "video/webm",
  "video/x-dv",
  "video/x-m4v",
  "video/x-mpeg",
  "video/x-ms-asf",
  "video/x-ms-wmv"
};

struct StandardType {
  const char* leading_mime_type;
  const char* const* standard_types;
  size_t standard_types_len;
};
static const StandardType kStandardTypes[] = {
  { "image/", kStandardImageTypes, arraysize(kStandardImageTypes) },
  { "audio/", kStandardAudioTypes, arraysize(kStandardAudioTypes) },
  { "video/", kStandardVideoTypes, arraysize(kStandardVideoTypes) },
  { NULL, NULL, 0 }
};

void GetExtensionsFromHardCodedMappings(
    const MimeInfo* mappings,
    size_t mappings_len,
    const std::string& leading_mime_type,
    base::hash_set<base::FilePath::StringType>* extensions) {
  base::FilePath::StringType extension;
  for (size_t i = 0; i < mappings_len; ++i) {
    if (StartsWithASCII(mappings[i].mime_type, leading_mime_type, false)) {
      std::vector<string> this_extensions;
      base::SplitStringUsingSubstr(mappings[i].extensions, ",",
                                   &this_extensions);
      for (size_t j = 0; j < this_extensions.size(); ++j) {
#if defined(OS_WIN)
        base::FilePath::StringType extension(
            base::UTF8ToWide(this_extensions[j]));
#else
        base::FilePath::StringType extension(this_extensions[j]);
#endif
        extensions->insert(extension);
      }
    }
  }
}

void GetExtensionsHelper(
    const char* const* standard_types,
    size_t standard_types_len,
    const std::string& leading_mime_type,
    base::hash_set<base::FilePath::StringType>* extensions) {
  for (size_t i = 0; i < standard_types_len; ++i) {
    g_mime_util.Get().GetPlatformExtensionsForMimeType(standard_types[i],
                                                       extensions);
  }

  // Also look up the extensions from hard-coded mappings in case that some
  // supported extensions are not registered in the system registry, like ogg.
  GetExtensionsFromHardCodedMappings(primary_mappings,
                                     arraysize(primary_mappings),
                                     leading_mime_type,
                                     extensions);

  GetExtensionsFromHardCodedMappings(secondary_mappings,
                                     arraysize(secondary_mappings),
                                     leading_mime_type,
                                     extensions);
}

// Note that the elements in the source set will be appended to the target
// vector.
template<class T>
void HashSetToVector(base::hash_set<T>* source, std::vector<T>* target) {
  size_t old_target_size = target->size();
  target->resize(old_target_size + source->size());
  size_t i = 0;
  for (typename base::hash_set<T>::iterator iter = source->begin();
       iter != source->end(); ++iter, ++i)
    (*target)[old_target_size + i] = *iter;
}
}

void GetExtensionsForMimeType(
    const std::string& unsafe_mime_type,
    std::vector<base::FilePath::StringType>* extensions) {
  if (unsafe_mime_type == "*/*" || unsafe_mime_type == "*")
    return;

  const std::string mime_type = StringToLowerASCII(unsafe_mime_type);
  base::hash_set<base::FilePath::StringType> unique_extensions;

  if (EndsWith(mime_type, "/*", true)) {
    std::string leading_mime_type = mime_type.substr(0, mime_type.length() - 1);

    // Find the matching StandardType from within kStandardTypes, or fall
    // through to the last (default) StandardType.
    const StandardType* type = NULL;
    for (size_t i = 0; i < arraysize(kStandardTypes); ++i) {
      type = &(kStandardTypes[i]);
      if (type->leading_mime_type &&
          leading_mime_type == type->leading_mime_type)
        break;
    }
    DCHECK(type);
    GetExtensionsHelper(type->standard_types,
                        type->standard_types_len,
                        leading_mime_type,
                        &unique_extensions);
  } else {
    g_mime_util.Get().GetPlatformExtensionsForMimeType(mime_type,
                                                       &unique_extensions);

    // Also look up the extensions from hard-coded mappings in case that some
    // supported extensions are not registered in the system registry, like ogg.
    GetExtensionsFromHardCodedMappings(primary_mappings,
                                       arraysize(primary_mappings),
                                       mime_type,
                                       &unique_extensions);

    GetExtensionsFromHardCodedMappings(secondary_mappings,
                                       arraysize(secondary_mappings),
                                       mime_type,
                                       &unique_extensions);
  }

  HashSetToVector(&unique_extensions, extensions);
}

void RemoveProprietaryMediaTypesAndCodecsForTests() {
  g_mime_util.Get().RemoveProprietaryMediaTypesAndCodecsForTests();
}

const std::string GetIANAMediaType(const std::string& mime_type) {
  for (size_t i = 0; i < arraysize(kIanaMediaTypes); ++i) {
    if (StartsWithASCII(mime_type, kIanaMediaTypes[i].matcher, true)) {
      return kIanaMediaTypes[i].name;
    }
  }
  return std::string();
}

CertificateMimeType GetCertificateMimeTypeForMimeType(
    const std::string& mime_type) {
  // Don't create a map, there is only one entry in the table,
  // except on Android.
  for (size_t i = 0; i < arraysize(supported_certificate_types); ++i) {
    if (mime_type == net::supported_certificate_types[i].mime_type)
      return net::supported_certificate_types[i].cert_type;
  }
  return CERTIFICATE_MIME_TYPE_UNKNOWN;
}

bool IsSupportedCertificateMimeType(const std::string& mime_type) {
  CertificateMimeType file_type =
      GetCertificateMimeTypeForMimeType(mime_type);
  return file_type != CERTIFICATE_MIME_TYPE_UNKNOWN;
}

void AddMultipartValueForUpload(const std::string& value_name,
                                const std::string& value,
                                const std::string& mime_boundary,
                                const std::string& content_type,
                                std::string* post_data) {
  DCHECK(post_data);
  // First line is the boundary.
  post_data->append("--" + mime_boundary + "\r\n");
  // Next line is the Content-disposition.
  post_data->append("Content-Disposition: form-data; name=\"" +
                    value_name + "\"\r\n");
  if (!content_type.empty()) {
    // If Content-type is specified, the next line is that.
    post_data->append("Content-Type: " + content_type + "\r\n");
  }
  // Leave an empty line and append the value.
  post_data->append("\r\n" + value + "\r\n");
}

void AddMultipartFinalDelimiterForUpload(const std::string& mime_boundary,
                                         std::string* post_data) {
  DCHECK(post_data);
  post_data->append("--" + mime_boundary + "--\r\n");
}

}  // namespace net
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root/net/base/mime_util.cc

DEFINITIONS
