Add a new implementation of SpdyUnsafeArena for code sharing between chromium
and envoy. This new implementation is merely a copy of SpdyUnsafeArenaImpl from
chromium (https://cs.chromium.org/chromium/src/net/spdy/platform/impl/spdy_unsafe_arena_impl.h?g=0&l=17) which itself is an older data structure used by SpdyHeaderBlock.
This new implemenation is not used as google3 impl. However, it's nice to have
it in quiche for code sharing between platforms.
Once this class is in quiche, chromium platform can point to this one instead of keeping the same code in SpdyUnsafeArenaImpl.
gfe-relnote: n/a (new class not in use)
PiperOrigin-RevId: 243133213
Change-Id: I52875503efc6be97c7a531d9c3e02780d66b88cc
diff --git a/spdy/core/spdy_simple_arena.cc b/spdy/core/spdy_simple_arena.cc
new file mode 100644
index 0000000..08cdc62
--- /dev/null
+++ b/spdy/core/spdy_simple_arena.cc
@@ -0,0 +1,103 @@
+// Copyright 2016 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/third_party/quiche/src/spdy/core/spdy_simple_arena.h"
+
+#include "net/third_party/quiche/src/spdy/platform/api/spdy_logging.h"
+
+namespace spdy {
+
+SpdySimpleArena::SpdySimpleArena(size_t block_size) : block_size_(block_size) {}
+
+SpdySimpleArena::~SpdySimpleArena() = default;
+
+SpdySimpleArena::SpdySimpleArena(SpdySimpleArena&& other) = default;
+SpdySimpleArena& SpdySimpleArena::operator=(SpdySimpleArena&& other) = default;
+
+char* SpdySimpleArena::Alloc(size_t size) {
+ Reserve(size);
+ Block& b = blocks_.back();
+ DCHECK_GE(b.size, b.used + size);
+ char* out = b.data.get() + b.used;
+ b.used += size;
+ return out;
+}
+
+char* SpdySimpleArena::Realloc(char* original, size_t oldsize, size_t newsize) {
+ DCHECK(!blocks_.empty());
+ Block& last = blocks_.back();
+ if (last.data.get() <= original && original < last.data.get() + last.size) {
+ // (original, oldsize) is in the last Block.
+ DCHECK_GE(last.data.get() + last.used, original + oldsize);
+ if (original + oldsize == last.data.get() + last.used) {
+ // (original, oldsize) was the most recent allocation,
+ if (original + newsize < last.data.get() + last.size) {
+ // (original, newsize) fits in the same Block.
+ last.used += newsize - oldsize;
+ return original;
+ }
+ }
+ }
+ char* out = Alloc(newsize);
+ memcpy(out, original, oldsize);
+ return out;
+}
+
+char* SpdySimpleArena::Memdup(const char* data, size_t size) {
+ char* out = Alloc(size);
+ memcpy(out, data, size);
+ return out;
+}
+
+void SpdySimpleArena::Free(char* data, size_t size) {
+ if (blocks_.empty()) {
+ return;
+ }
+ Block& b = blocks_.back();
+ if (size <= b.used && data + size == b.data.get() + b.used) {
+ // The memory region passed by the caller was the most recent allocation
+ // from the final block in this arena.
+ b.used -= size;
+ }
+}
+
+void SpdySimpleArena::Reset() {
+ blocks_.clear();
+ status_.bytes_allocated_ = 0;
+}
+
+void SpdySimpleArena::Reserve(size_t additional_space) {
+ if (blocks_.empty()) {
+ AllocBlock(std::max(additional_space, block_size_));
+ } else {
+ const Block& last = blocks_.back();
+ if (last.size < last.used + additional_space) {
+ AllocBlock(std::max(additional_space, block_size_));
+ }
+ }
+}
+
+void SpdySimpleArena::AllocBlock(size_t size) {
+ blocks_.push_back(Block(size));
+ status_.bytes_allocated_ += size;
+}
+
+SpdySimpleArena::Block::Block(size_t s) : data(new char[s]), size(s), used(0) {}
+
+SpdySimpleArena::Block::~Block() = default;
+
+SpdySimpleArena::Block::Block(SpdySimpleArena::Block&& other)
+ : size(other.size), used(other.used) {
+ data = std::move(other.data);
+}
+
+SpdySimpleArena::Block& SpdySimpleArena::Block::operator=(
+ SpdySimpleArena::Block&& other) {
+ size = other.size;
+ used = other.used;
+ data = std::move(other.data);
+ return *this;
+}
+
+} // namespace spdy
