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Export of internal Abseil changes

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--
a3e58c1870a9626039f4d178d2d599319bd9f8a8 by Matt Kulukundis <kfm@google.com>:

Allow MakeCordFromExternal to take a zero arg releaser.

PiperOrigin-RevId: 298650274

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01897c4a9bb99f3dc329a794019498ad345ddebd by Samuel Benzaquen <sbenza@google.com>:

Reduce library bloat for absl::Flag by moving the definition of base virtual functions to a .cc file.
This removes the duplicate symbols in user translation units and  has the side effect of moving the vtable definition too (re key function)

PiperOrigin-RevId: 298617920

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190f0d3782c63aed01046886d7fbc1be5bca2de9 by Derek Mauro <dmauro@google.com>:

Import GitHub #596: Unbreak stacktrace code for UWP apps

PiperOrigin-RevId: 298600834

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cd5cf6f8c87b35b85a9584e94da2a99057345b73 by Gennadiy Rozental <rogeeff@google.com>:

Use union of heap allocated pointer, one word atomic and two word atomic to represent flags value.

Any type T, which is trivially copy-able and with with sizeof(T) <= 8, will be stored in atomic int64_t.
Any type T, which is trivially copy-able and with with 8 < sizeof(T) <= 16, will be stored in atomic AlignedTwoWords.

We also introducing value storage type to distinguish these cases.

PiperOrigin-RevId: 298497200

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f8fe7bd53bfed601f002f521e34ab4bc083fc28b by Matthew Brown <matthewbr@google.com>:

Ensure a deep copy and proper equality on absl::Status::ErasePayload

PiperOrigin-RevId: 298482742

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a5c9ccddf4b04f444e3f7e27dbc14faf1fcb5373 by Gennadiy Rozental <rogeeff@google.com>:

Change ChunkIterator implementation to use fixed capacity collection of CordRep*. We can now assume that depth never exceeds 91. That makes comparison operator exception safe.

I've tested that with this CL we do not observe an overhead of chunk_end. Compiler optimized this iterator completely.

PiperOrigin-RevId: 298458472

--
327ea5e8910bc388b03389c730763f9823abfce5 by Abseil Team <absl-team@google.com>:

Minor cleanups in b-tree code:
- Rename some variables: fix issues of different param names between definition/declaration, move away from `x` as a default meaningless variable name.
- Make init_leaf/init_internal be non-static methods (they already take the node as the first parameter).
- In internal_emplace/try_shrink, update root/rightmost the same way as in insert_unique/insert_multi.
- Replace a TODO with a comment.

PiperOrigin-RevId: 298432836

--
8020ce9ec8558ee712d9733ae3d660ac1d3ffe1a by Abseil Team <absl-team@google.com>:

Guard against unnecessary copy in case the buffer is empty. This is important in cases were the user is explicitly tuning their chunks to match PiecewiseChunkSize().

PiperOrigin-RevId: 298366044

--
89324441d1c0c697c90ba7d8fc63639805fcaa9d by Abseil Team <absl-team@google.com>:

Internal change

PiperOrigin-RevId: 298219363
GitOrigin-RevId: a3e58c1870a9626039f4d178d2d599319bd9f8a8
Change-Id: I28dffc684b6fd0292b94807b88ec6664d5d0e183
This commit is contained in:
Abseil Team 2020-03-03 11:22:10 -08:00 • committed by Andy Soffer
parent 06f0e767d1
commit b19ba96766
24 changed files with 842 additions and 501 deletions
Download patch file Download diff file Expand all files Collapse all files

236
absl/strings/cord.cc
View file

@ -30,7 +30,6 @@
#include "absl/base/internal/raw_logging.h"
#include "absl/base/port.h"
#include "absl/container/fixed_array.h"
#include "absl/container/inlined_vector.h"
#include "absl/strings/escaping.h"
#include "absl/strings/internal/cord_internal.h"
#include "absl/strings/internal/resize_uninitialized.h"
@ -132,6 +131,14 @@ inline const CordRepExternal* CordRep::external() const {
return static_cast<const CordRepExternal*>(this);
}
using CordTreeConstPath = CordTreePath<const CordRep*, MaxCordDepth()>;
// This type is used to store the list of pending nodes during re-balancing.
// Its maximum size is 2 * MaxCordDepth() because the tree has a maximum
// possible depth of MaxCordDepth() and every concat node along a tree path
// could theoretically be split during rebalancing.
using RebalancingStack = CordTreePath<CordRep*, 2 * MaxCordDepth()>;
} // namespace cord_internal
static const size_t kFlatOverhead = offsetof(CordRep, data);
@ -180,8 +187,8 @@ static constexpr size_t TagToLength(uint8_t tag) {
// Enforce that kMaxFlatSize maps to a well-known exact tag value.
static_assert(TagToAllocatedSize(224) == kMaxFlatSize, "Bad tag logic");
constexpr uint64_t Fibonacci(unsigned char n, uint64_t a = 0, uint64_t b = 1) {
return n == 0 ? a : Fibonacci(n - 1, b, a + b);
constexpr uint64_t Fibonacci(uint8_t n, uint64_t a = 0, uint64_t b = 1) {
return n == 0 ? a : n == 1 ? b : Fibonacci(n - 1, b, a + b);
}
static_assert(Fibonacci(63) == 6557470319842,
@ -189,89 +196,68 @@ static_assert(Fibonacci(63) == 6557470319842,
// Minimum length required for a given depth tree -- a tree is considered
// balanced if
// length(t) >= min_length[depth(t)]
// The root node depth is allowed to become twice as large to reduce rebalancing
// for larger strings (see IsRootBalanced).
static constexpr uint64_t min_length[] = {
Fibonacci(2),
Fibonacci(3),
Fibonacci(4),
Fibonacci(5),
Fibonacci(6),
Fibonacci(7),
Fibonacci(8),
Fibonacci(9),
Fibonacci(10),
Fibonacci(11),
Fibonacci(12),
Fibonacci(13),
Fibonacci(14),
Fibonacci(15),
Fibonacci(16),
Fibonacci(17),
Fibonacci(18),
Fibonacci(19),
Fibonacci(20),
Fibonacci(21),
Fibonacci(22),
Fibonacci(23),
Fibonacci(24),
Fibonacci(25),
Fibonacci(26),
Fibonacci(27),
Fibonacci(28),
Fibonacci(29),
Fibonacci(30),
Fibonacci(31),
Fibonacci(32),
Fibonacci(33),
Fibonacci(34),
Fibonacci(35),
Fibonacci(36),
Fibonacci(37),
Fibonacci(38),
Fibonacci(39),
Fibonacci(40),
Fibonacci(41),
Fibonacci(42),
Fibonacci(43),
Fibonacci(44),
Fibonacci(45),
Fibonacci(46),
Fibonacci(47),
0xffffffffffffffffull, // Avoid overflow
};
// length(t) >= kMinLength[depth(t)]
// The node depth is allowed to become larger to reduce rebalancing
// for larger strings (see ShouldRebalance).
constexpr uint64_t kMinLength[] = {
Fibonacci(2), Fibonacci(3), Fibonacci(4), Fibonacci(5), Fibonacci(6),
Fibonacci(7), Fibonacci(8), Fibonacci(9), Fibonacci(10), Fibonacci(11),
Fibonacci(12), Fibonacci(13), Fibonacci(14), Fibonacci(15), Fibonacci(16),
Fibonacci(17), Fibonacci(18), Fibonacci(19), Fibonacci(20), Fibonacci(21),
Fibonacci(22), Fibonacci(23), Fibonacci(24), Fibonacci(25), Fibonacci(26),
Fibonacci(27), Fibonacci(28), Fibonacci(29), Fibonacci(30), Fibonacci(31),
Fibonacci(32), Fibonacci(33), Fibonacci(34), Fibonacci(35), Fibonacci(36),
Fibonacci(37), Fibonacci(38), Fibonacci(39), Fibonacci(40), Fibonacci(41),
Fibonacci(42), Fibonacci(43), Fibonacci(44), Fibonacci(45), Fibonacci(46),
Fibonacci(47), Fibonacci(48), Fibonacci(49), Fibonacci(50), Fibonacci(51),
Fibonacci(52), Fibonacci(53), Fibonacci(54), Fibonacci(55), Fibonacci(56),
Fibonacci(57), Fibonacci(58), Fibonacci(59), Fibonacci(60), Fibonacci(61),
Fibonacci(62), Fibonacci(63), Fibonacci(64), Fibonacci(65), Fibonacci(66),
Fibonacci(67), Fibonacci(68), Fibonacci(69), Fibonacci(70), Fibonacci(71),
Fibonacci(72), Fibonacci(73), Fibonacci(74), Fibonacci(75), Fibonacci(76),
Fibonacci(77), Fibonacci(78), Fibonacci(79), Fibonacci(80), Fibonacci(81),
Fibonacci(82), Fibonacci(83), Fibonacci(84), Fibonacci(85), Fibonacci(86),
Fibonacci(87), Fibonacci(88), Fibonacci(89), Fibonacci(90), Fibonacci(91),
Fibonacci(92), Fibonacci(93)};
static const int kMinLengthSize = ABSL_ARRAYSIZE(min_length);
static_assert(sizeof(kMinLength) / sizeof(uint64_t) ==
(cord_internal::MaxCordDepth() + 1),
"Not enough elements in kMinLength array to cover all the "
"supported Cord depth(s)");
// The inlined size to use with absl::InlinedVector.
//
// Note: The InlinedVectors in this file (and in cord.h) do not need to use
// the same value for their inlined size. The fact that they do is historical.
// It may be desirable for each to use a different inlined size optimized for
// that InlinedVector's usage.
//
// TODO(jgm): Benchmark to see if there's a more optimal value than 47 for
// the inlined vector size (47 exists for backward compatibility).
static const int kInlinedVectorSize = 47;
inline bool ShouldRebalance(const CordRep* node) {
if (node->tag != CONCAT) return false;
static inline bool IsRootBalanced(CordRep* node) {
if (node->tag != CONCAT) {
return true;
} else if (node->concat()->depth() <= 15) {
return true;
} else if (node->concat()->depth() > kMinLengthSize) {
return false;
} else {
// Allow depth to become twice as large as implied by fibonacci rule to
// reduce rebalancing for larger strings.
return (node->length >= min_length[node->concat()->depth() / 2]);
}
size_t node_depth = node->concat()->depth();
if (node_depth <= 15) return false;
// Rebalancing Cords is expensive, so we reduce how often rebalancing occurs
// by allowing shallow Cords to have twice the depth that the Fibonacci rule
// would otherwise imply. Deep Cords need to follow the rule more closely,
// however to ensure algorithm correctness. We implement this with linear
// interpolation. Cords of depth 16 are treated as though they have a depth
// of 16 * 1/2, and Cords of depth MaxCordDepth() interpolate to
// MaxCordDepth() * 1.
return node->length <
kMinLength[(node_depth * (cord_internal::MaxCordDepth() - 16)) /
(2 * cord_internal::MaxCordDepth() - 16 - node_depth)];
}
// Unlike root balancing condition this one is part of the re-balancing
// algorithm and has to be always matching against right depth for
// algorithm to be correct.
inline bool IsNodeBalanced(const CordRep* node) {
if (node->tag != CONCAT) return true;
size_t node_depth = node->concat()->depth();
return node->length >= kMinLength[node_depth];
}
static CordRep* Rebalance(CordRep* node);
static void DumpNode(CordRep* rep, bool include_data, std::ostream* os);
static bool VerifyNode(CordRep* root, CordRep* start_node,
static void DumpNode(const CordRep* rep, bool include_data, std::ostream* os);
static bool VerifyNode(const CordRep* root, const CordRep* start_node,
bool full_validation);
static inline CordRep* VerifyTree(CordRep* node) {
@ -318,7 +304,8 @@ __attribute__((preserve_most))
static void UnrefInternal(CordRep* rep) {
assert(rep != nullptr);
absl::InlinedVector<CordRep*, kInlinedVectorSize> pending;
cord_internal::RebalancingStack pending;
while (true) {
if (rep->tag == CONCAT) {
CordRepConcat* rep_concat = rep->concat();
@ -400,6 +387,11 @@ static void SetConcatChildren(CordRepConcat* concat, CordRep* left,
concat->length = left->length + right->length;
concat->set_depth(1 + std::max(Depth(left), Depth(right)));
ABSL_INTERNAL_CHECK(concat->depth() <= cord_internal::MaxCordDepth(),
"Cord depth exceeds max");
ABSL_INTERNAL_CHECK(concat->length >= left->length, "Cord is too long");
ABSL_INTERNAL_CHECK(concat->length >= right->length, "Cord is too long");
}
// Create a concatenation of the specified nodes.
@ -425,7 +417,7 @@ static CordRep* RawConcat(CordRep* left, CordRep* right) {
static CordRep* Concat(CordRep* left, CordRep* right) {
CordRep* rep = RawConcat(left, right);
if (rep != nullptr && !IsRootBalanced(rep)) {
if (rep != nullptr && ShouldRebalance(rep)) {
rep = Rebalance(rep);
}
return VerifyTree(rep);
@ -916,7 +908,7 @@ void Cord::Prepend(absl::string_view src) {
static CordRep* RemovePrefixFrom(CordRep* node, size_t n) {
if (n >= node->length) return nullptr;
if (n == 0) return Ref(node);
absl::InlinedVector<CordRep*, kInlinedVectorSize> rhs_stack;
cord_internal::CordTreeMutablePath rhs_stack;
while (node->tag == CONCAT) {
assert(n <= node->length);
@ -957,7 +949,7 @@ static CordRep* RemovePrefixFrom(CordRep* node, size_t n) {
static CordRep* RemoveSuffixFrom(CordRep* node, size_t n) {
if (n >= node->length) return nullptr;
if (n == 0) return Ref(node);
absl::InlinedVector<CordRep*, kInlinedVectorSize> lhs_stack;
absl::cord_internal::CordTreeMutablePath lhs_stack;
bool inplace_ok = node->refcount.IsOne();
while (node->tag == CONCAT) {
@ -1028,6 +1020,7 @@ void Cord::RemoveSuffix(size_t n) {
// Work item for NewSubRange().
struct SubRange {
SubRange() = default;
SubRange(CordRep* a_node, size_t a_pos, size_t a_n)
: node(a_node), pos(a_pos), n(a_n) {}
CordRep* node; // nullptr means concat last 2 results.
@ -1036,8 +1029,11 @@ struct SubRange {
};
static CordRep* NewSubRange(CordRep* node, size_t pos, size_t n) {
absl::InlinedVector<CordRep*, kInlinedVectorSize> results;
absl::InlinedVector<SubRange, kInlinedVectorSize> todo;
cord_internal::CordTreeMutablePath results;
// The algorithm below in worst case scenario adds up to 3 nodes to the `todo`
// list, but we also pop one out on every cycle. If original tree has depth d
// todo list can grew up to 2*d in size.
cord_internal::CordTreePath<SubRange, 2 * cord_internal::MaxCordDepth()> todo;
todo.push_back(SubRange(node, pos, n));
do {
const SubRange& sr = todo.back();
@ -1074,7 +1070,7 @@ static CordRep* NewSubRange(CordRep* node, size_t pos, size_t n) {
}
} while (!todo.empty());
assert(results.size() == 1);
return results[0];
return results.back();
}
Cord Cord::Subcord(size_t pos, size_t new_size) const {
@ -1113,11 +1109,12 @@ Cord Cord::Subcord(size_t pos, size_t new_size) const {
class CordForest {
public:
explicit CordForest(size_t length)
: root_length_(length), trees_(kMinLengthSize, nullptr) {}
explicit CordForest(size_t length) : root_length_(length), trees_({}) {}
void Build(CordRep* cord_root) {
std::vector<CordRep*> pending = {cord_root};
// We are adding up to two nodes to the `pending` list, but we also popping
// one, so the size of `pending` will never exceed `MaxCordDepth()`.
cord_internal::CordTreeMutablePath pending(cord_root);
while (!pending.empty()) {
CordRep* node = pending.back();
@ -1129,21 +1126,20 @@ class CordForest {
}
CordRepConcat* concat_node = node->concat();
if (concat_node->depth() >= kMinLengthSize ||
concat_node->length < min_length[concat_node->depth()]) {
pending.push_back(concat_node->right);
pending.push_back(concat_node->left);
if (concat_node->refcount.IsOne()) {
concat_node->left = concat_freelist_;
concat_freelist_ = concat_node;
} else {
Ref(concat_node->right);
Ref(concat_node->left);
Unref(concat_node);
}
} else {
if (IsNodeBalanced(concat_node)) {
AddNode(node);
continue;
}
pending.push_back(concat_node->right);
pending.push_back(concat_node->left);
if (concat_node->refcount.IsOne()) {
concat_node->left = concat_freelist_;
concat_freelist_ = concat_node;
} else {
Ref(concat_node->right);
Ref(concat_node->left);
Unref(concat_node);
}
}
}
@ -1175,7 +1171,7 @@ class CordForest {
// Collect together everything with which we will merge node
int i = 0;
for (; node->length > min_length[i + 1]; ++i) {
for (; node->length > kMinLength[i + 1]; ++i) {
auto& tree_at_i = trees_[i];
if (tree_at_i == nullptr) continue;
@ -1186,7 +1182,7 @@ class CordForest {
sum = AppendNode(node, sum);
// Insert sum into appropriate place in the forest
for (; sum->length >= min_length[i]; ++i) {
for (; sum->length >= kMinLength[i]; ++i) {
auto& tree_at_i = trees_[i];
if (tree_at_i == nullptr) continue;
@ -1194,7 +1190,7 @@ class CordForest {
tree_at_i = nullptr;
}
// min_length[0] == 1, which means sum->length >= min_length[0]
// kMinLength[0] == 1, which means sum->length >= kMinLength[0]
assert(i > 0);
trees_[i - 1] = sum;
}
@ -1227,9 +1223,7 @@ class CordForest {
}
size_t root_length_;
// use an inlined vector instead of a flat array to get bounds checking
absl::InlinedVector<CordRep*, kInlinedVectorSize> trees_;
std::array<cord_internal::CordRep*, cord_internal::MaxCordDepth()> trees_;
// List of concat nodes we can re-use for Cord balancing.
CordRepConcat* concat_freelist_ = nullptr;
@ -1841,18 +1835,18 @@ absl::string_view Cord::FlattenSlowPath() {
}
}
static void DumpNode(CordRep* rep, bool include_data, std::ostream* os) {
static void DumpNode(const CordRep* rep, bool include_data, std::ostream* os) {
const int kIndentStep = 1;
int indent = 0;
absl::InlinedVector<CordRep*, kInlinedVectorSize> stack;
absl::InlinedVector<int, kInlinedVectorSize> indents;
cord_internal::CordTreeConstPath stack;
cord_internal::CordTreePath<int, cord_internal::MaxCordDepth()> indents;
for (;;) {
*os << std::setw(3) << rep->refcount.Get();
*os << " " << std::setw(7) << rep->length;
*os << " [";
if (include_data) *os << static_cast<void*>(rep);
if (include_data) *os << static_cast<const void*>(rep);
*os << "]";
*os << " " << (IsRootBalanced(rep) ? 'b' : 'u');
*os << " " << (IsNodeBalanced(rep) ? 'b' : 'u');
*os << " " << std::setw(indent) << "";
if (rep->tag == CONCAT) {
*os << "CONCAT depth=" << Depth(rep) << "\n";
@ -1873,7 +1867,7 @@ static void DumpNode(CordRep* rep, bool include_data, std::ostream* os) {
} else {
*os << "FLAT cap=" << TagToLength(rep->tag) << " [";
if (include_data)
*os << absl::CEscape(std::string(rep->data, rep->length));
*os << absl::CEscape(absl::string_view(rep->data, rep->length));
*os << "]\n";
}
if (stack.empty()) break;
@ -1886,19 +1880,19 @@ static void DumpNode(CordRep* rep, bool include_data, std::ostream* os) {
ABSL_INTERNAL_CHECK(indents.empty(), "");
}
static std::string ReportError(CordRep* root, CordRep* node) {
static std::string ReportError(const CordRep* root, const CordRep* node) {
std::ostringstream buf;
buf << "Error at node " << node << " in:";
DumpNode(root, true, &buf);
return buf.str();
}
static bool VerifyNode(CordRep* root, CordRep* start_node,
static bool VerifyNode(const CordRep* root, const CordRep* start_node,
bool full_validation) {
absl::InlinedVector<CordRep*, 2> worklist;
cord_internal::CordTreeConstPath worklist;
worklist.push_back(start_node);
do {
CordRep* node = worklist.back();
const CordRep* node = worklist.back();
worklist.pop_back();
ABSL_INTERNAL_CHECK(node != nullptr, ReportError(root, node));
@ -1948,7 +1942,7 @@ static bool VerifyNode(CordRep* root, CordRep* start_node,
// Iterate over the tree. cur_node is never a leaf node and leaf nodes will
// never be appended to tree_stack. This reduces overhead from manipulating
// tree_stack.
absl::InlinedVector<const CordRep*, kInlinedVectorSize> tree_stack;
cord_internal::CordTreeConstPath tree_stack;
const CordRep* cur_node = rep;
while (true) {
const CordRep* next_node = nullptr;

100
absl/strings/cord.h
View file

@ -41,13 +41,13 @@
#include <iostream>
#include <iterator>
#include <string>
#include <type_traits>
#include "absl/base/internal/endian.h"
#include "absl/base/internal/invoke.h"
#include "absl/base/internal/per_thread_tls.h"
#include "absl/base/macros.h"
#include "absl/base/port.h"
#include "absl/container/inlined_vector.h"
#include "absl/functional/function_ref.h"
#include "absl/meta/type_traits.h"
#include "absl/strings/internal/cord_internal.h"
@ -66,6 +66,73 @@ template <typename H>
H HashFragmentedCord(H, const Cord&);
}
namespace cord_internal {
// It's expensive to keep a tree perfectly balanced, so instead we keep trees
// approximately balanced. A tree node N of depth D(N) that contains a string
// of L(N) characters is considered balanced if L >= Fibonacci(D + 2).
// The "+ 2" is used to ensure that every leaf node contains at least one
// character. Here we presume that
// Fibonacci(0) = 0
// Fibonacci(1) = 1
// Fibonacci(2) = 1
// Fibonacci(3) = 2
// ...
//
// Fibonacci numbers are convenient because it means when two balanced trees of
// the same depth are made the children of a new node, the resulting tree is
// guaranteed to also be balanced:
//
//
// L(left) >= Fibonacci(D(left) + 2)
// L(right) >= Fibonacci(D(right) + 2)
//
// L(left) + L(right) >= Fibonacci(D(left) + 2) + Fibonacci(D(right) + 2)
// L(left) + L(right) == L(new_tree)
//
// L(new_tree) >= 2 * Fibonacci(D(child) + 2)
// D(child) == D(new_tree) - 1
//
// L(new_tree) >= 2 * Fibonacci(D(new_tree) + 1)
// 2 * Fibonacci(N) >= Fibonacci(N + 1)
//
// L(new_tree) >= Fibonacci(D(new_tree) + 2)
//
//
// The 93rd Fibonacci number is the largest Fibonacci number that can be
// represented in 64 bits, so the size of a balanced Cord of depth 92 is too big
// for an unsigned 64 bit integer to hold. Therefore we can safely assume that
// the maximum depth of a Cord is 91.
constexpr size_t MaxCordDepth() { return 91; }
// This class models fixed max size stack of CordRep pointers.
// The elements are being pushed back and popped from the back.
template <typename CordRepPtr, size_t N>
class CordTreePath {
public:
CordTreePath() {}
explicit CordTreePath(CordRepPtr root) { push_back(root); }
bool empty() const { return size_ == 0; }
size_t size() const { return size_; }
void clear() { size_ = 0; }
CordRepPtr back() { return data_[size_ - 1]; }
void pop_back() {
--size_;
assert(size_ < N);
}
void push_back(CordRepPtr elem) { data_[size_++] = elem; }
private:
CordRepPtr data_[N];
size_t size_ = 0;
};
using CordTreeMutablePath = CordTreePath<CordRep*, MaxCordDepth()>;
} // namespace cord_internal
// A Cord is a sequence of characters.
class Cord {
private:
@ -114,7 +181,8 @@ class Cord {
// finished with `data`. The data must remain live and unchanging until the
// releaser is called. The requirements for the releaser are that it:
// * is move constructible,
// * supports `void operator()(absl::string_view) const`,
// * supports `void operator()(absl::string_view) const` or
// `void operator()() const`,
// * does not have alignment requirement greater than what is guaranteed by
// ::operator new. This is dictated by alignof(std::max_align_t) before
// C++17 and __STDCPP_DEFAULT_NEW_ALIGNMENT__ if compiling with C++17 or
@ -127,8 +195,8 @@ class Cord {
// FillBlock(block);
// return absl::MakeCordFromExternal(
// block->ToStringView(),
// [pool, block](absl::string_view /*ignored*/) {
// pool->FreeBlock(block);
// [pool, block](absl::string_view v) {
// pool->FreeBlock(block, v);
// });
// }
//
@ -282,8 +350,7 @@ class Cord {
absl::cord_internal::CordRep* current_leaf_ = nullptr;
// The number of bytes left in the `Cord` over which we are iterating.
size_t bytes_remaining_ = 0;
absl::InlinedVector<absl::cord_internal::CordRep*, 4>
stack_of_right_children_;
absl::cord_internal::CordTreeMutablePath stack_of_right_children_;
};
// Returns an iterator to the first chunk of the `Cord`.
@ -667,6 +734,21 @@ ExternalRepReleaserPair NewExternalWithUninitializedReleaser(
absl::string_view data, ExternalReleaserInvoker invoker,
size_t releaser_size);
struct Rank1 {};
struct Rank0 : Rank1 {};
template <typename Releaser, typename = ::absl::base_internal::InvokeT<
Releaser, absl::string_view>>
void InvokeReleaser(Rank0, Releaser&& releaser, absl::string_view data) {
::absl::base_internal::Invoke(std::forward<Releaser>(releaser), data);
}
template <typename Releaser,
typename = ::absl::base_internal::InvokeT<Releaser>>
void InvokeReleaser(Rank1, Releaser&& releaser, absl::string_view) {
::absl::base_internal::Invoke(std::forward<Releaser>(releaser));
}
// Creates a new `CordRep` that owns `data` and `releaser` and returns a pointer
// to it, or `nullptr` if `data` was empty.
template <typename Releaser>
@ -684,14 +766,14 @@ CordRep* NewExternalRep(absl::string_view data, Releaser&& releaser) {
using ReleaserType = absl::decay_t<Releaser>;
if (data.empty()) {
// Never create empty external nodes.
::absl::base_internal::Invoke(
ReleaserType(std::forward<Releaser>(releaser)), data);
InvokeReleaser(Rank0{}, ReleaserType(std::forward<Releaser>(releaser)),
data);
return nullptr;
}
auto releaser_invoker = [](void* type_erased_releaser, absl::string_view d) {
auto* my_releaser = static_cast<ReleaserType*>(type_erased_releaser);
::absl::base_internal::Invoke(std::move(*my_releaser), d);
InvokeReleaser(Rank0{}, std::move(*my_releaser), d);
my_releaser->~ReleaserType();
return sizeof(Releaser);
};

56
absl/strings/cord_test.cc
View file

@ -1032,6 +1032,19 @@ TEST(ConstructFromExternal, MoveOnlyReleaser) {
EXPECT_TRUE(invoked);
}
TEST(ConstructFromExternal, NoArgLambda) {
bool invoked = false;
(void)absl::MakeCordFromExternal("dummy", [&invoked]() { invoked = true; });
EXPECT_TRUE(invoked);
}
TEST(ConstructFromExternal, StringViewArgLambda) {
bool invoked = false;
(void)absl::MakeCordFromExternal(
"dummy", [&invoked](absl::string_view) { invoked = true; });
EXPECT_TRUE(invoked);
}
TEST(ConstructFromExternal, NonTrivialReleaserDestructor) {
struct Releaser {
explicit Releaser(bool* destroyed) : destroyed(destroyed) {}
@ -1346,6 +1359,49 @@ TEST(CordChunkIterator, Operations) {
VerifyChunkIterator(subcords, 128);
}
TEST(CordChunkIterator, MaxLengthFullTree) {
absl::Cord cord;
size_t size = 1;
AddExternalMemory("x", &cord);
EXPECT_EQ(cord.size(), size);
for (int i = 0; i < 63; ++i) {
cord.Prepend(absl::Cord(cord));
size <<= 1;
EXPECT_EQ(cord.size(), size);
auto chunk_it = cord.chunk_begin();
EXPECT_EQ(*chunk_it, "x");
}
EXPECT_DEATH_IF_SUPPORTED(
(cord.Prepend(absl::Cord(cord)), *cord.chunk_begin()),
"Cord is too long");
}
TEST(CordChunkIterator, MaxDepth) {
// By reusing nodes, it's possible in pathological cases to build a Cord that
// exceeds both the maximum permissible length and depth. In this case, the
// violation of the maximum depth is reported.
absl::Cord left_child;
AddExternalMemory("x", &left_child);
absl::Cord root = left_child;
for (int i = 0; i < 91; ++i) {
size_t new_size = left_child.size() + root.size();
root.Prepend(left_child);
EXPECT_EQ(root.size(), new_size);
auto chunk_it = root.chunk_begin();
EXPECT_EQ(*chunk_it, "x");
std::swap(left_child, root);
}
EXPECT_DEATH_IF_SUPPORTED(root.Prepend(left_child), "Cord depth exceeds max");
}
TEST(CordCharIterator, Traits) {
static_assert(std::is_copy_constructible<absl::Cord::CharIterator>::value,
"");