diff options
Diffstat (limited to 'chromium/net/base/sdch_filter.cc')
| -rw-r--r-- | chromium/net/base/sdch_filter.cc | 388 |
1 files changed, 0 insertions, 388 deletions
diff --git a/chromium/net/base/sdch_filter.cc b/chromium/net/base/sdch_filter.cc deleted file mode 100644 index 89891b66f49..00000000000 --- a/chromium/net/base/sdch_filter.cc +++ /dev/null @@ -1,388 +0,0 @@ -// Copyright (c) 2011 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 "net/base/sdch_filter.h" - -#include <limits.h> -#include <ctype.h> -#include <algorithm> - -#include "base/logging.h" -#include "base/metrics/histogram.h" -#include "net/base/sdch_manager.h" - -#include "sdch/open-vcdiff/src/google/vcdecoder.h" - -namespace net { - -SdchFilter::SdchFilter(const FilterContext& filter_context) - : filter_context_(filter_context), - decoding_status_(DECODING_UNINITIALIZED), - dictionary_hash_(), - dictionary_hash_is_plausible_(false), - dictionary_(NULL), - dest_buffer_excess_(), - dest_buffer_excess_index_(0), - source_bytes_(0), - output_bytes_(0), - possible_pass_through_(false) { - bool success = filter_context.GetMimeType(&mime_type_); - DCHECK(success); - success = filter_context.GetURL(&url_); - DCHECK(success); -} - -SdchFilter::~SdchFilter() { - // All code here is for gathering stats, and can be removed when SDCH is - // considered stable. - - static int filter_use_count = 0; - ++filter_use_count; - if (META_REFRESH_RECOVERY == decoding_status_) { - UMA_HISTOGRAM_COUNTS("Sdch3.FilterUseBeforeDisabling", filter_use_count); - } - - if (vcdiff_streaming_decoder_.get()) { - if (!vcdiff_streaming_decoder_->FinishDecoding()) { - decoding_status_ = DECODING_ERROR; - SdchManager::SdchErrorRecovery(SdchManager::INCOMPLETE_SDCH_CONTENT); - // Make it possible for the user to hit reload, and get non-sdch content. - // Note this will "wear off" quickly enough, and is just meant to assure - // in some rare case that the user is not stuck. - SdchManager::BlacklistDomain(url_); - UMA_HISTOGRAM_COUNTS("Sdch3.PartialBytesIn", - static_cast<int>(filter_context_.GetByteReadCount())); - UMA_HISTOGRAM_COUNTS("Sdch3.PartialVcdiffIn", source_bytes_); - UMA_HISTOGRAM_COUNTS("Sdch3.PartialVcdiffOut", output_bytes_); - } - } - - if (!dest_buffer_excess_.empty()) { - // Filter chaining error, or premature teardown. - SdchManager::SdchErrorRecovery(SdchManager::UNFLUSHED_CONTENT); - UMA_HISTOGRAM_COUNTS("Sdch3.UnflushedBytesIn", - static_cast<int>(filter_context_.GetByteReadCount())); - UMA_HISTOGRAM_COUNTS("Sdch3.UnflushedBufferSize", - dest_buffer_excess_.size()); - UMA_HISTOGRAM_COUNTS("Sdch3.UnflushedVcdiffIn", source_bytes_); - UMA_HISTOGRAM_COUNTS("Sdch3.UnflushedVcdiffOut", output_bytes_); - } - - if (filter_context_.IsCachedContent()) { - // Not a real error, but it is useful to have this tally. - // TODO(jar): Remove this stat after SDCH stability is validated. - SdchManager::SdchErrorRecovery(SdchManager::CACHE_DECODED); - return; // We don't need timing stats, and we aready got ratios. - } - - switch (decoding_status_) { - case DECODING_IN_PROGRESS: { - if (output_bytes_) - UMA_HISTOGRAM_PERCENTAGE("Sdch3.Network_Decode_Ratio_a", - static_cast<int>( - (filter_context_.GetByteReadCount() * 100) / output_bytes_)); - UMA_HISTOGRAM_COUNTS("Sdch3.Network_Decode_Bytes_VcdiffOut_a", - output_bytes_); - filter_context_.RecordPacketStats(FilterContext::SDCH_DECODE); - - // Allow latency experiments to proceed. - SdchManager::Global()->SetAllowLatencyExperiment(url_, true); - return; - } - case PASS_THROUGH: { - filter_context_.RecordPacketStats(FilterContext::SDCH_PASSTHROUGH); - return; - } - case DECODING_UNINITIALIZED: { - SdchManager::SdchErrorRecovery(SdchManager::UNINITIALIZED); - return; - } - case WAITING_FOR_DICTIONARY_SELECTION: { - SdchManager::SdchErrorRecovery(SdchManager::PRIOR_TO_DICTIONARY); - return; - } - case DECODING_ERROR: { - SdchManager::SdchErrorRecovery(SdchManager::DECODE_ERROR); - return; - } - case META_REFRESH_RECOVERY: { - // Already accounted for when set. - return; - } - } // end of switch. -} - -bool SdchFilter::InitDecoding(Filter::FilterType filter_type) { - if (decoding_status_ != DECODING_UNINITIALIZED) - return false; - - // Handle case where sdch filter is guessed, but not required. - if (FILTER_TYPE_SDCH_POSSIBLE == filter_type) - possible_pass_through_ = true; - - // Initialize decoder only after we have a dictionary in hand. - decoding_status_ = WAITING_FOR_DICTIONARY_SELECTION; - return true; -} - -#ifndef NDEBUG -static const char* kDecompressionErrorHtml = - "<head><META HTTP-EQUIV=\"Refresh\" CONTENT=\"0\"></head>" - "<div style=\"position:fixed;top:0;left:0;width:100%;border-width:thin;" - "border-color:black;border-style:solid;text-align:left;font-family:arial;" - "font-size:10pt;foreground-color:black;background-color:white\">" - "An error occurred. This page will be reloaded shortly. " - "Or press the \"reload\" button now to reload it immediately." - "</div>"; -#else -static const char* kDecompressionErrorHtml = - "<head><META HTTP-EQUIV=\"Refresh\" CONTENT=\"0\"></head>"; -#endif - -Filter::FilterStatus SdchFilter::ReadFilteredData(char* dest_buffer, - int* dest_len) { - int available_space = *dest_len; - *dest_len = 0; // Nothing output yet. - - if (!dest_buffer || available_space <= 0) - return FILTER_ERROR; - - if (WAITING_FOR_DICTIONARY_SELECTION == decoding_status_) { - FilterStatus status = InitializeDictionary(); - if (FILTER_NEED_MORE_DATA == status) - return FILTER_NEED_MORE_DATA; - if (FILTER_ERROR == status) { - DCHECK_EQ(DECODING_ERROR, decoding_status_); - DCHECK_EQ(0u, dest_buffer_excess_index_); - DCHECK(dest_buffer_excess_.empty()); - // This is where we try very hard to do error recovery, and make this - // protocol robust in the face of proxies that do many different things. - // If we decide that things are looking very bad (too hard to recover), - // we may even issue a "meta-refresh" to reload the page without an SDCH - // advertisement (so that we are sure we're not hurting anything). - // - // Watch out for an error page inserted by the proxy as part of a 40x - // error response. When we see such content molestation, we certainly - // need to fall into the meta-refresh case. - if (filter_context_.GetResponseCode() == 404) { - // We could be more generous, but for now, only a "NOT FOUND" code will - // cause a pass through. All other bad codes will fall into a - // meta-refresh. - SdchManager::SdchErrorRecovery(SdchManager::PASS_THROUGH_404_CODE); - decoding_status_ = PASS_THROUGH; - } else if (filter_context_.GetResponseCode() != 200) { - // We need to meta-refresh, with SDCH disabled. - } else if (filter_context_.IsCachedContent() - && !dictionary_hash_is_plausible_) { - // We must have hit the back button, and gotten content that was fetched - // before we *really* advertised SDCH and a dictionary. - SdchManager::SdchErrorRecovery(SdchManager::PASS_THROUGH_OLD_CACHED); - decoding_status_ = PASS_THROUGH; - } else if (possible_pass_through_) { - // This is the potentially most graceful response. There really was no - // error. We were just overly cautious when we added a TENTATIVE_SDCH. - // We added the sdch coding tag, and it should not have been added. - // This can happen in server experiments, where the server decides - // not to use sdch, even though there is a dictionary. To be - // conservative, we locally added the tentative sdch (fearing that a - // proxy stripped it!) and we must now recant (pass through). - SdchManager::SdchErrorRecovery(SdchManager::DISCARD_TENTATIVE_SDCH); - // However.... just to be sure we don't get burned by proxies that - // re-compress with gzip or other system, we can sniff to see if this - // is compressed data etc. For now, we do nothing, which gets us into - // the meta-refresh result. - // TODO(jar): Improve robustness by sniffing for valid text that we can - // actual use re: decoding_status_ = PASS_THROUGH; - } else if (dictionary_hash_is_plausible_) { - // We need a meta-refresh since we don't have the dictionary. - // The common cause is a restart of the browser, where we try to render - // cached content that was saved when we had a dictionary. - } else if (filter_context_.IsSdchResponse()) { - // This is a very corrupt SDCH request response. We can't decode it. - // We'll use a meta-refresh, and get content without asking for SDCH. - // This will also progressively disable SDCH for this domain. - } else { - // One of the first 9 bytes precluded consideration as a hash. - // This can't be an SDCH payload, even though the server said it was. - // This is a major error, as the server or proxy tagged this SDCH even - // though it is not! - // Meta-refresh won't help, as we didn't advertise an SDCH dictionary!! - // Worse yet, meta-refresh could lead to an infinite refresh loop. - SdchManager::SdchErrorRecovery(SdchManager::PASSING_THROUGH_NON_SDCH); - decoding_status_ = PASS_THROUGH; - // ... but further back-off on advertising SDCH support. - SdchManager::BlacklistDomain(url_); - } - - if (decoding_status_ == PASS_THROUGH) { - dest_buffer_excess_ = dictionary_hash_; // Send what we scanned. - } else { - // This is where we try to do the expensive meta-refresh. - if (std::string::npos == mime_type_.find("text/html")) { - // Since we can't do a meta-refresh (along with an exponential - // backoff), we'll just make sure this NEVER happens again. - SdchManager::BlacklistDomainForever(url_); - if (filter_context_.IsCachedContent()) - SdchManager::SdchErrorRecovery( - SdchManager::CACHED_META_REFRESH_UNSUPPORTED); - else - SdchManager::SdchErrorRecovery( - SdchManager::META_REFRESH_UNSUPPORTED); - return FILTER_ERROR; - } - // HTML content means we can issue a meta-refresh, and get the content - // again, perhaps without SDCH (to be safe). - if (filter_context_.IsCachedContent()) { - // Cached content is probably a startup tab, so we'll just get fresh - // content and try again, without disabling sdch. - SdchManager::SdchErrorRecovery( - SdchManager::META_REFRESH_CACHED_RECOVERY); - } else { - // Since it wasn't in the cache, we definately need at least some - // period of blacklisting to get the correct content. - SdchManager::BlacklistDomain(url_); - SdchManager::SdchErrorRecovery(SdchManager::META_REFRESH_RECOVERY); - } - decoding_status_ = META_REFRESH_RECOVERY; - // Issue a meta redirect with SDCH disabled. - dest_buffer_excess_ = kDecompressionErrorHtml; - } - } else { - DCHECK_EQ(DECODING_IN_PROGRESS, decoding_status_); - } - } - - int amount = OutputBufferExcess(dest_buffer, available_space); - *dest_len += amount; - dest_buffer += amount; - available_space -= amount; - DCHECK_GE(available_space, 0); - - if (available_space <= 0) - return FILTER_OK; - DCHECK(dest_buffer_excess_.empty()); - DCHECK_EQ(0u, dest_buffer_excess_index_); - - if (decoding_status_ != DECODING_IN_PROGRESS) { - if (META_REFRESH_RECOVERY == decoding_status_) { - // Absorb all input data. We've already output page reload HTML. - next_stream_data_ = NULL; - stream_data_len_ = 0; - return FILTER_NEED_MORE_DATA; - } - if (PASS_THROUGH == decoding_status_) { - // We must pass in available_space, but it will be changed to bytes_used. - FilterStatus result = CopyOut(dest_buffer, &available_space); - // Accumulate the returned count of bytes_used (a.k.a., available_space). - *dest_len += available_space; - return result; - } - DCHECK(false); - decoding_status_ = DECODING_ERROR; - return FILTER_ERROR; - } - - if (!next_stream_data_ || stream_data_len_ <= 0) - return FILTER_NEED_MORE_DATA; - - bool ret = vcdiff_streaming_decoder_->DecodeChunk( - next_stream_data_, stream_data_len_, &dest_buffer_excess_); - // Assume all data was used in decoding. - next_stream_data_ = NULL; - source_bytes_ += stream_data_len_; - stream_data_len_ = 0; - output_bytes_ += dest_buffer_excess_.size(); - if (!ret) { - vcdiff_streaming_decoder_.reset(NULL); // Don't call it again. - decoding_status_ = DECODING_ERROR; - SdchManager::SdchErrorRecovery(SdchManager::DECODE_BODY_ERROR); - return FILTER_ERROR; - } - - amount = OutputBufferExcess(dest_buffer, available_space); - *dest_len += amount; - dest_buffer += amount; - available_space -= amount; - if (0 == available_space && !dest_buffer_excess_.empty()) - return FILTER_OK; - return FILTER_NEED_MORE_DATA; -} - -Filter::FilterStatus SdchFilter::InitializeDictionary() { - const size_t kServerIdLength = 9; // Dictionary hash plus null from server. - size_t bytes_needed = kServerIdLength - dictionary_hash_.size(); - DCHECK_GT(bytes_needed, 0u); - if (!next_stream_data_) - return FILTER_NEED_MORE_DATA; - if (static_cast<size_t>(stream_data_len_) < bytes_needed) { - dictionary_hash_.append(next_stream_data_, stream_data_len_); - next_stream_data_ = NULL; - stream_data_len_ = 0; - return FILTER_NEED_MORE_DATA; - } - dictionary_hash_.append(next_stream_data_, bytes_needed); - DCHECK(kServerIdLength == dictionary_hash_.size()); - stream_data_len_ -= bytes_needed; - DCHECK_LE(0, stream_data_len_); - if (stream_data_len_ > 0) - next_stream_data_ += bytes_needed; - else - next_stream_data_ = NULL; - - DCHECK(!dictionary_.get()); - dictionary_hash_is_plausible_ = true; // Assume plausible, but check. - - SdchManager::Dictionary* dictionary = NULL; - if ('\0' == dictionary_hash_[kServerIdLength - 1]) - SdchManager::Global()->GetVcdiffDictionary(std::string(dictionary_hash_, 0, - kServerIdLength - 1), - url_, &dictionary); - else - dictionary_hash_is_plausible_ = false; - - if (!dictionary) { - DCHECK(dictionary_hash_.size() == kServerIdLength); - // Since dictionary was not found, check to see if hash was even plausible. - for (size_t i = 0; i < kServerIdLength - 1; ++i) { - char base64_char = dictionary_hash_[i]; - if (!isalnum(base64_char) && '-' != base64_char && '_' != base64_char) { - dictionary_hash_is_plausible_ = false; - break; - } - } - if (dictionary_hash_is_plausible_) - SdchManager::SdchErrorRecovery(SdchManager::DICTIONARY_HASH_NOT_FOUND); - else - SdchManager::SdchErrorRecovery(SdchManager::DICTIONARY_HASH_MALFORMED); - decoding_status_ = DECODING_ERROR; - return FILTER_ERROR; - } - dictionary_ = dictionary; - vcdiff_streaming_decoder_.reset(new open_vcdiff::VCDiffStreamingDecoder); - vcdiff_streaming_decoder_->SetAllowVcdTarget(false); - vcdiff_streaming_decoder_->StartDecoding(dictionary_->text().data(), - dictionary_->text().size()); - decoding_status_ = DECODING_IN_PROGRESS; - return FILTER_OK; -} - -int SdchFilter::OutputBufferExcess(char* const dest_buffer, - size_t available_space) { - if (dest_buffer_excess_.empty()) - return 0; - DCHECK(dest_buffer_excess_.size() > dest_buffer_excess_index_); - size_t amount = std::min(available_space, - dest_buffer_excess_.size() - dest_buffer_excess_index_); - memcpy(dest_buffer, dest_buffer_excess_.data() + dest_buffer_excess_index_, - amount); - dest_buffer_excess_index_ += amount; - if (dest_buffer_excess_.size() <= dest_buffer_excess_index_) { - DCHECK(dest_buffer_excess_.size() == dest_buffer_excess_index_); - dest_buffer_excess_.clear(); - dest_buffer_excess_index_ = 0; - } - return amount; -} - -} // namespace net |