Update HPACK implementation to draft 05

net/spdy/hpack_encoding_context.cc

 // Copyright 2014 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/spdy/hpack_encoding_context.h"
 
 #include <cstddef>
 
 #include "base/logging.h"
 #include "base/macros.h"
 #include "net/spdy/hpack_entry.h"
 
 namespace net {
 
+using base::StringPiece;
+
 namespace {
 
 // An entry in the static table. Must be a POD in order to avoid
 // static initializers, i.e. no user-defined constructors or
 // destructors.
 struct StaticEntry {
   const char* const name;
   const size_t name_len;
   const char* const value;
   const size_t value_len;
 };
 
 // The "constructor" for a StaticEntry that computes the lengths at
 // compile time.
 #define STATIC_ENTRY(name, value) \
   { name, arraysize(name) - 1, value, arraysize(value) - 1 }
 
 const StaticEntry kStaticTable[] = {
-  STATIC_ENTRY(":authority"                  , ""),             // 0
-  STATIC_ENTRY(":method"                     , "GET"),          // 1
-  STATIC_ENTRY(":method"                     , "POST"),         // 2
-  STATIC_ENTRY(":path"                       , "/"),            // 3
-  STATIC_ENTRY(":path"                       , "/index.html"),  // 4
-  STATIC_ENTRY(":scheme"                     , "http"),         // 5
-  STATIC_ENTRY(":scheme"                     , "https"),        // 6
-  STATIC_ENTRY(":status"                     , "200"),          // 7
-  STATIC_ENTRY(":status"                     , "500"),          // 8
-  STATIC_ENTRY(":status"                     , "404"),          // 9
-  STATIC_ENTRY(":status"                     , "403"),          // 10
-  STATIC_ENTRY(":status"                     , "400"),          // 11
-  STATIC_ENTRY(":status"                     , "401"),          // 12
-  STATIC_ENTRY("accept-charset"              , ""),             // 13
-  STATIC_ENTRY("accept-encoding"             , ""),             // 14
-  STATIC_ENTRY("accept-language"             , ""),             // 15
-  STATIC_ENTRY("accept-ranges"               , ""),             // 16
-  STATIC_ENTRY("accept"                      , ""),             // 17
-  STATIC_ENTRY("access-control-allow-origin" , ""),             // 18
-  STATIC_ENTRY("age"                         , ""),             // 19
-  STATIC_ENTRY("allow"                       , ""),             // 20
-  STATIC_ENTRY("authorization"               , ""),             // 21
-  STATIC_ENTRY("cache-control"               , ""),             // 22
-  STATIC_ENTRY("content-disposition"         , ""),             // 23
-  STATIC_ENTRY("content-encoding"            , ""),             // 24
-  STATIC_ENTRY("content-language"            , ""),             // 25
-  STATIC_ENTRY("content-length"              , ""),             // 26
-  STATIC_ENTRY("content-location"            , ""),             // 27
-  STATIC_ENTRY("content-range"               , ""),             // 28
-  STATIC_ENTRY("content-type"                , ""),             // 29
-  STATIC_ENTRY("cookie"                      , ""),             // 30
-  STATIC_ENTRY("date"                        , ""),             // 31
-  STATIC_ENTRY("etag"                        , ""),             // 32
-  STATIC_ENTRY("expect"                      , ""),             // 33
-  STATIC_ENTRY("expires"                     , ""),             // 34
-  STATIC_ENTRY("from"                        , ""),             // 35
-  STATIC_ENTRY("if-match"                    , ""),             // 36
-  STATIC_ENTRY("if-modified-since"           , ""),             // 37
-  STATIC_ENTRY("if-none-match"               , ""),             // 38
-  STATIC_ENTRY("if-range"                    , ""),             // 39
-  STATIC_ENTRY("if-unmodified-since"         , ""),             // 40
-  STATIC_ENTRY("last-modified"               , ""),             // 41
-  STATIC_ENTRY("link"                        , ""),             // 42
-  STATIC_ENTRY("location"                    , ""),             // 43
-  STATIC_ENTRY("max-forwards"                , ""),             // 44
-  STATIC_ENTRY("proxy-authenticate"          , ""),             // 45
-  STATIC_ENTRY("proxy-authorization"         , ""),             // 46
-  STATIC_ENTRY("range"                       , ""),             // 47
-  STATIC_ENTRY("referer"                     , ""),             // 48
-  STATIC_ENTRY("refresh"                     , ""),             // 49
-  STATIC_ENTRY("retry-after"                 , ""),             // 50
-  STATIC_ENTRY("server"                      , ""),             // 51
-  STATIC_ENTRY("set-cookie"                  , ""),             // 52
-  STATIC_ENTRY("strict-transport-security"   , ""),             // 53
-  STATIC_ENTRY("transfer-encoding"           , ""),             // 54
-  STATIC_ENTRY("user-agent"                  , ""),             // 55
-  STATIC_ENTRY("vary"                        , ""),             // 56
-  STATIC_ENTRY("via"                         , ""),             // 57
-  STATIC_ENTRY("www-authenticate"            , ""),             // 58
+  STATIC_ENTRY(":authority"                  , ""),             // 1
+  STATIC_ENTRY(":method"                     , "GET"),          // 2
+  STATIC_ENTRY(":method"                     , "POST"),         // 3
+  STATIC_ENTRY(":path"                       , "/"),            // 4
+  STATIC_ENTRY(":path"                       , "/index.html"),  // 5
+  STATIC_ENTRY(":scheme"                     , "http"),         // 6
+  STATIC_ENTRY(":scheme"                     , "https"),        // 7
+  STATIC_ENTRY(":status"                     , "200"),          // 8
+  STATIC_ENTRY(":status"                     , "500"),          // 9
+  STATIC_ENTRY(":status"                     , "404"),          // 10
+  STATIC_ENTRY(":status"                     , "403"),          // 11
+  STATIC_ENTRY(":status"                     , "400"),          // 12
+  STATIC_ENTRY(":status"                     , "401"),          // 13
+  STATIC_ENTRY("accept-charset"              , ""),             // 14
+  STATIC_ENTRY("accept-encoding"             , ""),             // 15
+  STATIC_ENTRY("accept-language"             , ""),             // 16
+  STATIC_ENTRY("accept-ranges"               , ""),             // 17
+  STATIC_ENTRY("accept"                      , ""),             // 18
+  STATIC_ENTRY("access-control-allow-origin" , ""),             // 19
+  STATIC_ENTRY("age"                         , ""),             // 20
+  STATIC_ENTRY("allow"                       , ""),             // 21
+  STATIC_ENTRY("authorization"               , ""),             // 22
+  STATIC_ENTRY("cache-control"               , ""),             // 23
+  STATIC_ENTRY("content-disposition"         , ""),             // 24
+  STATIC_ENTRY("content-encoding"            , ""),             // 25
+  STATIC_ENTRY("content-language"            , ""),             // 26
+  STATIC_ENTRY("content-length"              , ""),             // 27
+  STATIC_ENTRY("content-location"            , ""),             // 28
+  STATIC_ENTRY("content-range"               , ""),             // 29
+  STATIC_ENTRY("content-type"                , ""),             // 30
+  STATIC_ENTRY("cookie"                      , ""),             // 31
+  STATIC_ENTRY("date"                        , ""),             // 32
+  STATIC_ENTRY("etag"                        , ""),             // 33
+  STATIC_ENTRY("expect"                      , ""),             // 34
+  STATIC_ENTRY("expires"                     , ""),             // 35
+  STATIC_ENTRY("from"                        , ""),             // 36
+  STATIC_ENTRY("host"                        , ""),             // 37
+  STATIC_ENTRY("if-match"                    , ""),             // 38
+  STATIC_ENTRY("if-modified-since"           , ""),             // 39
+  STATIC_ENTRY("if-none-match"               , ""),             // 40
+  STATIC_ENTRY("if-range"                    , ""),             // 41
+  STATIC_ENTRY("if-unmodified-since"         , ""),             // 42
+  STATIC_ENTRY("last-modified"               , ""),             // 43
+  STATIC_ENTRY("link"                        , ""),             // 44
+  STATIC_ENTRY("location"                    , ""),             // 45
+  STATIC_ENTRY("max-forwards"                , ""),             // 46
+  STATIC_ENTRY("proxy-authenticate"          , ""),             // 47
+  STATIC_ENTRY("proxy-authorization"         , ""),             // 48
+  STATIC_ENTRY("range"                       , ""),             // 49
+  STATIC_ENTRY("referer"                     , ""),             // 50
+  STATIC_ENTRY("refresh"                     , ""),             // 51
+  STATIC_ENTRY("retry-after"                 , ""),             // 52
+  STATIC_ENTRY("server"                      , ""),             // 53
+  STATIC_ENTRY("set-cookie"                  , ""),             // 54
+  STATIC_ENTRY("strict-transport-security"   , ""),             // 55
+  STATIC_ENTRY("transfer-encoding"           , ""),             // 56
+  STATIC_ENTRY("user-agent"                  , ""),             // 57
+  STATIC_ENTRY("vary"                        , ""),             // 58
+  STATIC_ENTRY("via"                         , ""),             // 59
+  STATIC_ENTRY("www-authenticate"            , ""),             // 60
 };
 
 #undef STATIC_ENTRY
 
 const size_t kStaticEntryCount = arraysize(kStaticTable);
 
 }  // namespace
 
 const uint32 HpackEncodingContext::kUntouched = HpackEntry::kUntouched;
 
 HpackEncodingContext::HpackEncodingContext() {}
 
 HpackEncodingContext::~HpackEncodingContext() {}
 
-uint32 HpackEncodingContext::GetEntryCount() const {
-  return header_table_.GetEntryCount() + kStaticEntryCount;
+uint32 HpackEncodingContext::GetMutableEntryCount() const {
+  return header_table_.GetEntryCount();
 }
 
-base::StringPiece HpackEncodingContext::GetNameAt(uint32 index) const {
-  CHECK_LT(index, GetEntryCount());
-  if (index >= header_table_.GetEntryCount()) {
+uint32 HpackEncodingContext::GetEntryCount() const {
+  return GetMutableEntryCount() + kStaticEntryCount;
+}
+
+StringPiece HpackEncodingContext::GetNameAt(uint32 index) const {
+  CHECK_GE(index, 1u);
+  CHECK_LE(index, GetEntryCount());
+  if (index > header_table_.GetEntryCount()) {
     const StaticEntry& entry =
-        kStaticTable[index - header_table_.GetEntryCount()];
-    return base::StringPiece(entry.name, entry.name_len);
+        kStaticTable[index - header_table_.GetEntryCount() - 1];
+    return StringPiece(entry.name, entry.name_len);
   }
   return header_table_.GetEntry(index).name();
 }
 
-base::StringPiece HpackEncodingContext::GetValueAt(uint32 index) const {
-  CHECK_LT(index, GetEntryCount());
-  if (index >= header_table_.GetEntryCount()) {
+StringPiece HpackEncodingContext::GetValueAt(uint32 index) const {
+  CHECK_GE(index, 1u);
+  CHECK_LE(index, GetEntryCount());
+  if (index > header_table_.GetEntryCount()) {
     const StaticEntry& entry =
-        kStaticTable[index - header_table_.GetEntryCount()];
-    return base::StringPiece(entry.value, entry.value_len);
+        kStaticTable[index - header_table_.GetEntryCount() - 1];
+    return StringPiece(entry.value, entry.value_len);
   }
   return header_table_.GetEntry(index).value();
 }
 
 bool HpackEncodingContext::IsReferencedAt(uint32 index) const {
-  CHECK_LT(index, GetEntryCount());
-  if (index >= header_table_.GetEntryCount())
+  CHECK_GE(index, 1u);
+  CHECK_LE(index, GetEntryCount());
+  if (index > header_table_.GetEntryCount())
     return false;
   return header_table_.GetEntry(index).IsReferenced();
 }
 
 uint32 HpackEncodingContext::GetTouchCountAt(uint32 index) const {
-  CHECK_LT(index, GetEntryCount());
-  if (index >= header_table_.GetEntryCount())
+  CHECK_GE(index, 1u);
+  CHECK_LE(index, GetEntryCount());
+  if (index > header_table_.GetEntryCount())
     return 0;
   return header_table_.GetEntry(index).TouchCount();
 }
 
 void HpackEncodingContext::SetReferencedAt(uint32 index, bool referenced) {
   header_table_.GetMutableEntry(index)->SetReferenced(referenced);
 }
 
 void HpackEncodingContext::AddTouchesAt(uint32 index, uint32 touch_count) {
   header_table_.GetMutableEntry(index)->AddTouches(touch_count);
 }
 
 void HpackEncodingContext::ClearTouchesAt(uint32 index) {
   header_table_.GetMutableEntry(index)->ClearTouches();
 }
 
 void HpackEncodingContext::SetMaxSize(uint32 max_size) {
   header_table_.SetMaxSize(max_size);
 }
 
 bool HpackEncodingContext::ProcessIndexedHeader(
     uint32 index,
-    int32* new_index,
+    uint32* new_index,
     std::vector<uint32>* removed_referenced_indices) {
-  if (index >= GetEntryCount())
+  if (index < 1 || index > GetEntryCount())
     return false;
 
-  if (index < header_table_.GetEntryCount()) {
+  if (index <= header_table_.GetEntryCount()) {
     *new_index = index;
     removed_referenced_indices->clear();
     HpackEntry* entry = header_table_.GetMutableEntry(index);
     entry->SetReferenced(!entry->IsReferenced());
   } else {
     // TODO(akalin): Make HpackEntry know about owned strings and
     // non-owned strings so that it can potentially avoid copies here.
     HpackEntry entry(GetNameAt(index), GetValueAt(index));
 
     header_table_.TryAddEntry(entry, new_index, removed_referenced_indices);
-    if (*new_index >= 0) {
+    if (*new_index >= 1) {
       header_table_.GetMutableEntry(*new_index)->SetReferenced(true);
     }
   }
   return true;
 }
 
 bool HpackEncodingContext::ProcessLiteralHeaderWithIncrementalIndexing(
-    base::StringPiece name,
-    base::StringPiece value,
-    int32* index,
+    StringPiece name,
+    StringPiece value,
+    uint32* index,
     std::vector<uint32>* removed_referenced_indices) {
   HpackEntry entry(name, value);
   header_table_.TryAddEntry(entry, index, removed_referenced_indices);
-  if (*index >= 0) {
+  if (*index >= 1) {
     header_table_.GetMutableEntry(*index)->SetReferenced(true);
   }
   return true;
 }
 
 }  // namespace net