Implement basic classes for HPACK (HTTP/2 compression)

net/spdy/hpack_encoding_context.cc

Index: net/spdy/hpack_encoding_context.cc
diff --git a/net/spdy/hpack_encoding_context.cc b/net/spdy/hpack_encoding_context.cc
new file mode 100644
index 0000000000000000000000000000000000000000..cdcbfb3e553446839de8caa407fcf2c33c524878
--- /dev/null
+++ b/net/spdy/hpack_encoding_context.cc
@@ -0,0 +1,194 @@
+#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 {
+
+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
+};
+
+#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;
+}
+
+base::StringPiece HpackEncodingContext::GetNameAt(uint32 index) const {
+  CHECK_LT(index, GetEntryCount());
+  if (index >= header_table_.GetEntryCount()) {
+    const StaticEntry& entry =
+        kStaticTable[index - header_table_.GetEntryCount()];
+    return base::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()) {
+    const StaticEntry& entry =
+        kStaticTable[index - header_table_.GetEntryCount()];
+    return base::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())
+    return false;
+  return header_table_.GetEntry(index).IsReferenced();
+}
+
+uint32 HpackEncodingContext::GetTouchCountAt(uint32 index) const {
+  CHECK_LT(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,
+    std::vector<uint32>* removed_referenced_indices) {
+  if (index >= GetEntryCount())
+    return false;
+
+  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) {
+      header_table_.GetMutableEntry(*new_index)->SetReferenced(true);
+    }
+  }
+  return true;
+}
+
+bool HpackEncodingContext::ProcessLiteralHeaderWithIncrementalIndexing(
+    base::StringPiece name,
+    base::StringPiece value,
+    int32* index,
+    std::vector<uint32>* removed_referenced_indices) {
+  HpackEntry entry(name, value);
+  header_table_.TryAddEntry(entry, index, removed_referenced_indices);
+  if (*index >= 0) {
+    header_table_.GetMutableEntry(*index)->SetReferenced(true);
+  }
+  return true;
+}
+
+}  // namespace net