CMakeLists.txt

@@ -52,8 +52,8 @@ elseif(CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang")
   set(WHOLE_ARCHIVE_PREFIX "-Wl,-force_load,")
   # set(NO_WHOLE_ARCHIVE_PREFIX "")
 elseif(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
-  # set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -gz")
-  # set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -gz")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -gz")
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -gz")
   # set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -static-libgcc -static-libstdc++")
   # set(CMAKE_C_FLAGS "${CMAKE_CXX_FLAGS} -static-libgcc -static-libstdc++")
 
@@ -153,6 +153,7 @@ set(TILE_SRCS
     "tile/base/encoding/detail/hex_chars.cc"
     "tile/base/encoding/hex.cc"
     "tile/base/encoding/percent.cc"
+    "tile/base/exposed_var.cc"
     "tile/base/internal/background_task_host.cc"
     "tile/base/internal/background_task_host.h"
     "tile/base/internal/case_insensitive_hash_map.h"
@@ -279,6 +280,7 @@ if(TILE_BUILD_TESTS)
     target_sources(${PROJECT_NAME}_test_all PRIVATE ${test_file})
   endmacro()
 
+  tile_add_test(base_exposed_var_test "tile/base/exposed_var_test.cc")
 tile_add_test(fiber_detail_scheduler_test "tile/fiber/detail/scheduler_test.cc")
   tile_add_test(base_internal_meta_test "tile/base/internal/meta_test.cc")
   # tile_add_test(net_internal_http_engine_test

third_party/json/json.h

@@ -1,7 +0,0 @@
-#ifndef TILE__THIRD_PARTY_JSON_JSON_H
-#define TILE__THIRD_PARTY_JSON_JSON_H
-
-#pragma once
-#include "nlohmann/json.hpp"
-
-#endif // TILE__THIRD_PARTY_JSON_JSON_H

tile/base/exposed_var.cc

@@ -0,0 +1,300 @@
+#include "tile/base/exposed_var.h"
+
+#include "tile/base/internal/logging.h"
+#include "tile/base/internal/move_on_copy.h"
+#include "tile/base/string.h"
+
+namespace tile {
+namespace exposed_var {
+
+namespace {
+#define CHECK_PATH(path)                                                       \
+  TILE_CHECK((path).size() <= 1 || (path).back() != '/',                       \
+             "Invalid path: [{}].", path);                                     \
+  TILE_CHECK((path).find("//") == tile::Slice::npos, "Invalid path: [{}].",    \
+             path);
+
+#define CHECK_RELATIVE_PATH(path)                                              \
+  CHECK_PATH(path);                                                            \
+  TILE_CHECK((path).empty() || (path).front() != '/', "Invalid path: [{}].",   \
+             path);
+
+#define CHECK_ABSOLUTE_PATH(path)                                              \
+  CHECK_PATH(path);                                                            \
+  TILE_CHECK((path).empty() || (path).front() == '/', "Invalid path: [{}]",    \
+             path);
+
+std::pair<Slice, Slice> SplitFirstPart(Slice path) {
+  auto pos = path.find_first_of('/');
+  if (pos == tile::Slice::npos) {
+    return std::make_pair(path, "");
+  } else {
+    return std::make_pair(path.substr(0, pos), path.substr(pos + 1));
+  }
+}
+
+std::pair<Slice, Slice> SplitLastPart(Slice path) {
+  auto pos = path.find_last_of('/');
+  if (pos == tile::Slice::npos) {
+    return std::make_pair("", path);
+  }
+
+  return std::make_pair(path.substr(0, pos), path.substr(pos + 1));
+}
+
+std::string JoinPath(Slice a, Slice b) {
+  if (EndsWith(b, "/")) {
+    b.RemoveSuffix(1);
+  }
+
+  if (EndsWith(a, "/")) {
+    a.RemoveSuffix(1);
+  }
+
+  if (b.empty()) {
+    return a.ToString();
+  }
+  if (a.empty()) {
+    return b.ToString();
+  }
+
+  return a.ToString() + "/" + b.ToString();
+}
+
+std::string SubstituteEscapedSlashForZero(Slice path) {
+  TILE_CHECK(path.find('\0') == tile::Slice::npos);
+  return Replace(path, "\\/", "\0");
+}
+
+std::string SubstituteZeroForEscapedSlash(Slice path) {
+  return Replace(path, "\0", "\\/");
+}
+
+std::string UnescapeZeroToPlainSlash(Slice path) {
+  return Replace(path, "\0", "/");
+}
+
+} // namespace
+
+ExposedVarGroup::Handle
+ExposedVarGroup::Add(Slice rel_path, std::function<Json::Value()> value) {
+
+  auto real_path = SubstituteEscapedSlashForZero(rel_path);
+  CHECK_RELATIVE_PATH(rel_path);
+
+  auto path_and_name = SplitLastPart(real_path);
+  auto name = path_and_name.second.ToString();
+
+  auto moved_func = tile::MakeMoveOnCopy(value);
+  return CreateUpto(path_and_name.first)
+      ->AddDirect(
+          name,
+          [name, moved_func](Slice expected) -> std::optional<Json::Value> {
+            auto jsv = moved_func.Ref()();
+            if (expected.empty()) {
+              return jsv;
+            }
+
+            auto real_path = SubstituteEscapedSlashForZero(expected);
+            Json::Value *ptr = &jsv;
+            auto pieces = Split(real_path, '/');
+
+            for (auto &&e : pieces) {
+              auto unescaped = UnescapeZeroToPlainSlash({e.data(), e.size()});
+              if (ptr->isObject()) {
+                if (ptr->isMember(unescaped)) {
+                  ptr = &(*ptr)[unescaped];
+                } else {
+                  return {};
+                }
+              } else if (ptr->isArray()) {
+                auto index = TryParse<std::size_t>(unescaped);
+                if (index && *index < ptr->size()) {
+                  ptr = &(*ptr)[static_cast<Json::ArrayIndex>(*index)];
+                } else {
+                  return {};
+                }
+              } else {
+                return {};
+              }
+            }
+
+            return *ptr;
+          });
+}
+
+ExposedVarGroup::Handle
+ExposedVarGroup::Add(Slice rel_path, ExposedVarDynamicTree *dynamic_tree) {
+  auto real_path = SubstituteEscapedSlashForZero(rel_path);
+  CHECK_RELATIVE_PATH(real_path);
+  auto path_and_name = SplitLastPart(real_path);
+  auto name = path_and_name.second.ToString();
+
+  return CreateUpto(path_and_name.first)
+      ->AddDirect(name, [dynamic_tree](Slice inner_path) {
+        return dynamic_tree->TryGet(inner_path);
+      });
+}
+
+ExposedVarGroup *ExposedVarGroup::FindOrCreate(Slice abs_path) {
+  auto real_path = SubstituteEscapedSlashForZero(abs_path);
+  CHECK_ABSOLUTE_PATH(real_path);
+
+  return Root()->CreateUpto(real_path.substr(1));
+}
+std::optional<Json::Value> ExposedVarGroup::TryGet(Slice abs_path) {
+  auto real_path = SubstituteEscapedSlashForZero(abs_path);
+  TILE_CHECK(!real_path.empty());
+  CHECK_ABSOLUTE_PATH(real_path);
+
+  if (real_path == "/") {
+    return Root()->Dump();
+  }
+
+  Slice left_path;
+  auto rel_path = real_path.substr(1);
+  auto parent = Root()->FindLowest(rel_path, &left_path);
+
+  auto name_and_rest = SplitFirstPart(left_path);
+  if (name_and_rest.first.empty()) {
+    return parent->Dump();
+  }
+
+  auto s = name_and_rest.first.ToString();
+  std::lock_guard<std::mutex> lk(parent->lock_);
+  auto iter = parent->leaves_.find(s);
+  if (iter != parent->leaves_.end()) {
+    return iter->second(SubstituteZeroForEscapedSlash(name_and_rest.second));
+  } else {
+    auto iter = parent->nodes_.find(s);
+    if (iter != parent->nodes_.end()) {
+      return iter->second->Dump();
+    } else {
+      return {};
+    }
+  }
+}
+
+ExposedVarGroup::ExposedVarGroup(std::string abs_path)
+    : abs_path_(std::move(abs_path)) {
+  CHECK_ABSOLUTE_PATH(abs_path);
+}
+
+ExposedVarGroup *ExposedVarGroup::Root() {
+  static ExposedVarGroup evg("/");
+  return &evg;
+}
+const std::string &ExposedVarGroup::AbsolutePath() const { return abs_path_; }
+
+ExposedVarGroup *ExposedVarGroup::FindLowest(Slice rel_path, Slice *left) {
+  CHECK_RELATIVE_PATH(rel_path);
+  auto current = this;
+
+  while (!rel_path.empty()) {
+    auto name_and_rest = SplitFirstPart(rel_path);
+
+    std::lock_guard<std::mutex> lk(current->lock_);
+    auto iter = current->nodes_.find(name_and_rest.first.ToString());
+    if (iter == current->nodes_.end()) {
+      break;
+    } else {
+      current = &*iter->second;
+    }
+
+    rel_path = name_and_rest.second;
+  }
+
+  if (left) {
+    *left = rel_path;
+  }
+  return current;
+}
+
+ExposedVarGroup *ExposedVarGroup::CreateUpto(Slice rel_path) {
+  CHECK_RELATIVE_PATH(rel_path);
+
+  Slice left_path;
+  auto current = FindLowest(rel_path, &left_path);
+
+  auto pieces = Split(left_path, '/');
+
+  for (auto &&e : pieces) {
+    auto s = e.ToString();
+
+    std::lock_guard<std::mutex> lk(current->lock_);
+    auto p = JoinPath(current->AbsolutePath(), s);
+
+    TILE_CHECK(
+        current->leaves_.find(s) == current->leaves_.end(),
+        "Path [{}] has already been used: A value is registered at [{}].",
+        rel_path, p);
+
+    TILE_CHECK(current->nodes_.find(s) == current->nodes_.end());
+    auto evg = std::unique_ptr<ExposedVarGroup>(new ExposedVarGroup(p));
+    current->nodes_[s] = std::move(evg);
+    current = &*(current->nodes_[s]);
+  }
+
+  TILE_CHECK(EndsWith(current->AbsolutePath(), rel_path), "[{}] vs [{}]",
+             current->AbsolutePath(), rel_path);
+  return current;
+}
+
+ExposedVarGroup::Handle ExposedVarGroup::AddDirect(Slice name, Getter value) {
+  auto s = name.ToString();
+  std::lock_guard<std::mutex> lk(lock_);
+
+  TILE_CHECK(leaves_.find(s) == leaves_.end(),
+             "Value [{}] has already been registered at [{}].", name,
+             AbsolutePath());
+  TILE_CHECK(nodes_.find(s) == nodes_.end(), "Path [{}] has already been used.",
+             JoinPath(AbsolutePath(), name));
+  leaves_[s] = std::move(value);
+
+  return Deferred([this, s] {
+    std::lock_guard<std::mutex> lk(lock_);
+    TILE_CHECK_EQ(leaves_.erase(s), 1);
+  });
+}
+
+Json::Value ExposedVarGroup::Dump() const {
+  std::lock_guard<std::mutex> lk(lock_);
+  Json::Value jsv;
+  for (auto &&node : nodes_) {
+    jsv[UnescapeZeroToPlainSlash(node.first)] = node.second->Dump();
+  }
+
+  for (auto &&leave : leaves_) {
+    jsv[UnescapeZeroToPlainSlash(leave.first)] = *leave.second("");
+  }
+
+  return jsv;
+}
+
+ExposedVarDynamicTree::ExposedVarDynamicTree(
+    Slice rel_path, std::function<Json::Value()> getter,
+    ExposedVarGroup *parent)
+    : getter_(std::move(getter)) {
+  handle_ = parent->Add(rel_path, this);
+}
+
+std::optional<Json::Value> ExposedVarDynamicTree::TryGet(Slice rel_path) const {
+  auto real_path = SubstituteEscapedSlashForZero(rel_path);
+  auto jsv = getter_();
+  Json::Value *ptr = &jsv;
+
+  auto pieces = Split(real_path, '/');
+  for (auto &&e : pieces) {
+    auto unescaped = UnescapeZeroToPlainSlash({e.data(), e.size()});
+    ptr = &(*ptr)[unescaped];
+  }
+
+  if (ptr->isNull()) {
+    return {};
+  }
+
+  return *ptr;
+}
+
+} // namespace exposed_var
+} // namespace tile

tile/base/exposed_var.h

@@ -3,13 +3,145 @@
 
 #pragma once
 
-#include "inja/inja.h"
+#include "tile/base/deferred.h"
+#include "tile/base/internal/meta.h"
+#include "tile/base/optional.h"
+#include "tile/base/slice.h"
+#include "json/value.h"
+
+#include <unordered_map>
 
 namespace tile {
 namespace exposed_var {
-template <typename T> inja::json ToJson(const T &t) {
+
+template <typename T>
+auto ToJsonValue(const T &t)
+    -> enable_if_t<std::is_same<T, Json::Value>::value, Json::Value> {
+  return t;
 }
 
+template <typename T>
+auto ToJsonValue(const T &t)
+    -> enable_if_t<std::is_integral<T>::value && std::is_unsigned<T>::value,
+                   Json::Value> {
+  return Json::Value(static_cast<Json::UInt64>(t));
+}
+
+template <typename T>
+auto ToJsonValue(const T &t)
+    -> enable_if_t<std::is_integral<T>::value && !std::is_unsigned<T>::value,
+                   Json::Value> {
+  return Json::Value(static_cast<Json::Int64>(t));
+}
+
+template <typename T>
+auto ToJsonValue(const T &t)
+    -> enable_if_t<std::is_floating_point<T>::value ||
+                       std::is_same<T, std::string>::value ||
+                       std::is_same<T, const char *>::value ||
+                       std::is_same<T, bool>::value,
+                   Json::Value> {
+  return Json::Value(t);
+}
+
+template <typename T>
+auto ToJsonValue(const T &t)
+    -> enable_if_t<std::is_same<std::string,
+                                decltype(format_as(std::declval<T>()))>::value,
+                   Json::Value> {
+  return Json::Value(format_as(t));
+}
+
+template <class T> Json::Value ToJsonValue(const std::atomic<T> &v) {
+  return ToJsonValue(v.load(std::memory_order_relaxed));
+}
+
+class ExposedVarDynamicTree;
+
+class ExposedVarGroup {
+public:
+  using Handle = Deferred;
+
+  Handle Add(Slice rel_path, std::function<Json::Value()> value);
+  Handle Add(Slice rel_path, ExposedVarDynamicTree *dyanmic_tree);
+  static ExposedVarGroup *FindOrCreate(Slice abs_path);
+  static std::optional<Json::Value> TryGet(Slice abs_path);
+
+private:
+  using Getter = std::function<std::optional<Json::Value>(Slice)>;
+
+  explicit ExposedVarGroup(std::string abs_path);
+  const std::string &AbsolutePath() const;
+
+  ExposedVarGroup *FindLowest(Slice rel_path, Slice *left);
+  ExposedVarGroup *CreateUpto(Slice rel_path);
+  Handle AddDirect(Slice name, Getter getter);
+  Json::Value Dump() const;
+  static ExposedVarGroup *Root();
+
+private:
+  std::string abs_path_;
+  mutable std::mutex lock_;
+
+  std::unordered_map<std::string, std::unique_ptr<ExposedVarGroup>> nodes_;
+  std::unordered_map<std::string, Getter> leaves_;
+};
+
+template <typename T> class ExposedVar {
+public:
+  ExposedVar(Slice rel_path) {
+    LinkToParent(rel_path, ExposedVarGroup::FindOrCreate("/"));
+  }
+
+  template <typename U>
+  ExposedVar(Slice rel_path, U &&initial_value,
+             ExposedVarGroup *parent = ExposedVarGroup::FindOrCreate("/"))
+      : obj_(std::forward<U>(initial_value)) {
+    LinkToParent(rel_path, parent);
+  }
+
+  T *operator->() noexcept { return &obj_; }
+  T &operator*() noexcept { return obj_; }
+
+private:
+  void LinkToParent(Slice rel_path, ExposedVarGroup *parent) {
+    handle_ = parent->Add(rel_path,
+                          [this] { return exposed_var::ToJsonValue(obj_); });
+  }
+
+private:
+  T obj_{};
+  ExposedVarGroup::Handle handle_;
+};
+
+template <typename T> class ExposedVarDynamic {
+public:
+  ExposedVarDynamic(
+      Slice rel_path, std::function<T()> getter,
+      ExposedVarGroup *parent = ExposedVarGroup::FindOrCreate("/"))
+      : getter_(std::move(getter)) {
+    handle_ = parent->Add(
+        rel_path, [this] { return exposed_var::ToJsonValue(getter_()); });
+  }
+
+private:
+  std::function<T()> getter_;
+  ExposedVarGroup::Handle handle_;
+};
+
+class ExposedVarDynamicTree {
+public:
+  ExposedVarDynamicTree(
+      Slice rel_path, std::function<Json::Value()> getter,
+      ExposedVarGroup *parent = ExposedVarGroup::FindOrCreate("/"));
+
+  std::optional<Json::Value> TryGet(Slice rel_path) const;
+
+private:
+  std::function<Json::Value()> getter_;
+  ExposedVarGroup::Handle handle_;
+};
+
 } // namespace exposed_var
 } // namespace tile
 

tile/base/exposed_var_test.cc

@@ -0,0 +1,6 @@
+#include "tile/base/exposed_var.h"
+
+#include "gtest/gtest.h"
+#include "json/json.h"
+
+namespace tile {}

tile/base/slice.h

@@ -91,6 +91,16 @@ public:
 
   constexpr Slice(const Slice &other) : data_(other.data_), len_(other.len_) {}
 
+  char front() const {
+    assert(len_ > 0);
+    return *data_;
+  }
+
+  char back() const {
+    assert(len_ > 0);
+    return data_[len_ - 1];
+  }
+
   Slice &operator=(const Slice &other) {
     data_ = other.data_;
     len_ = other.len_;
@@ -131,6 +141,8 @@ public:
 
   std::size_t find(Slice s, std::size_t pos = 0) const;
 
+  std::size_t find_first_of(Slice s) const { return find(s); }
+
   // TODO: Optimize it
   std::size_t find_last_of(Slice s) const {
     if (s.empty() || s.size() > size()) {