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// Copyright 2022 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 "media/formats/hls/playlist.h"
#include "media/formats/hls/items.h"
#include "media/formats/hls/playlist_common.h"
#include "media/formats/hls/tags.h"
#include "media/formats/hls/types.h"
#include "url/gurl.h"
namespace media::hls {
Playlist::Playlist(GURL uri,
types::DecimalInteger version,
bool independent_segments)
: uri_(std::move(uri)),
version_(version),
independent_segments_(independent_segments) {}
Playlist::Playlist(Playlist&&) = default;
Playlist& Playlist::operator=(Playlist&&) = default;
Playlist::~Playlist() = default;
// static
ParseStatus::Or<Playlist::Identification> Playlist::IdentifyPlaylist(
base::StringPiece source) {
absl::optional<Kind> playlist_kind;
absl::optional<XVersionTag> version_tag;
// Iterate through playlist lines until we can identify the version and the
// playlist kind.
SourceLineIterator iter(source);
while (!playlist_kind.has_value() || !version_tag.has_value()) {
auto item_result = GetNextLineItem(&iter);
if (item_result.has_error()) {
auto error = std::move(item_result).error();
// Only tolerated error is EOF
if (error.code() == ParseStatusCode::kReachedEOF) {
break;
}
return error;
}
auto item = std::move(item_result).value();
if (auto* tag = absl::get_if<TagItem>(&item)) {
// We can't make any assumptions on unknown tags
if (!tag->GetName().has_value()) {
continue;
}
const auto tag_name = tag->GetName().value();
// If this is a version tag, try parsing it to determine the version
if (tag_name == ToTagName(CommonTagName::kXVersion)) {
auto error = ParseUniqueTag(*tag, version_tag);
if (error.has_value()) {
return std::move(error).value();
}
// Ensure that the version is supported by this implementation
if (version_tag->version < Playlist::kMinSupportedVersion ||
version_tag->version > Playlist::kMaxSupportedVersion) {
return ParseStatusCode::kPlaylistHasUnsupportedVersion;
}
continue;
}
// Otherwise use the tag's kind to identify playlist kind without
// attempting to parse it.
switch (GetTagKind(tag_name)) {
case TagKind::kCommonTag:
break;
case TagKind::kMultivariantPlaylistTag:
if (playlist_kind == Kind::kMediaPlaylist) {
return ParseStatusCode::kMediaPlaylistHasMultivariantPlaylistTag;
}
playlist_kind = Kind::kMultivariantPlaylist;
break;
case TagKind::kMediaPlaylistTag:
if (playlist_kind == Kind::kMultivariantPlaylist) {
return ParseStatusCode::kMultivariantPlaylistHasMediaPlaylistTag;
}
playlist_kind = Kind::kMediaPlaylist;
break;
}
}
}
return Identification{
// If the playlist did not contain a version tag, version is implicitly
// `kDefaultVersion`.
.version = version_tag ? version_tag->version : kDefaultVersion,
// Media playlists must contain the EXT-X-TARGETDURATION tag, so if we
// never encountered a media playlist tag it must be an (empty)
// multivariant playlist.
.kind =
playlist_kind ? playlist_kind.value() : Kind::kMultivariantPlaylist,
};
}
} // namespace media::hls
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