1 files changed, 218 insertions, 0 deletions

diff --git a/server/src/sqlite3.cpp b/server/src/sqlite3.cpp
new file mode 100644
index 0000000..3e0d64a
--- /dev/null
+++ b/server/src/sqlite3.cpp
@@ -0,0 +1,218 @@
+module;
+
+#include <sqlite3.h>
+
+module routemon:sqlite3$impl;
+
+import :sqlite3;
+
+namespace routemon::sqlite3 {
+
+mutex_guard::mutex_guard(::sqlite3_mutex* mut) noexcept : mut_{mut} {}
+
+mutex_guard::~mutex_guard() { ::sqlite3_mutex_leave(mut_); }
+
+auto do_guarded(::sqlite3_mutex* mut, std::invocable<mutex_guard const&> auto f)
+    -> decltype(f(std::declval<mutex_guard const&>()))
+{
+  return f(mutex_guard{mut});
+}
+
+auto do_guarded(::sqlite3* dbc, std::invocable<mutex_guard const&> auto f)
+    -> decltype(f(std::declval<mutex_guard const&>()))
+{
+  return do_guarded(::sqlite3_db_mutex(dbc), f);
+}
+
+error::error(mutex_guard const&, int code, ::sqlite3* dbc)
+  : code_{code}, message_{::sqlite3_errmsg(dbc)}
+{
+}
+
+error::error(int code) : code_{code}, message_{::sqlite3_errstr(code)} {}
+
+[[nodiscard]] auto error::what() const noexcept -> char const*
+{
+  return message_.c_str();
+}
+
+[[nodiscard]] auto error::code() const noexcept -> int { return code_; }
+
+statement::statement(::sqlite3_stmt* stmt) : stmt_{stmt} {}
+statement::statement(statement&& s) noexcept
+{
+  stmt_ = s.stmt_;
+  s.stmt_ = nullptr;
+}
+statement::~statement() { ::sqlite3_finalize(stmt_); }
+auto statement::get() -> ::sqlite3_stmt* { return stmt_; }
+
+row_reader::row_reader(statement stmt) : stmt_{std::move(stmt)} {}
+
+auto row_reader::is_null(int col) -> bool
+{
+  return ::sqlite3_column_type(stmt_.get(), col) == SQLITE_NULL;
+}
+
+auto row_reader::ncols() -> std::size_t
+{
+  auto const mncols = util::size_from_int(::sqlite3_data_count(stmt_.get()));
+  if (!mncols.has_value())
+    throw std::logic_error{"got unexpected negative amount of columns"};
+  return *mncols;
+}
+
+auto row_reader::scan(int col, std::string& s) -> void
+{
+  if (::sqlite3_column_type(stmt_.get(), col) != SQLITE_TEXT)
+    throw std::invalid_argument{"invalid type for scan"};
+  unsigned char const* chs = ::sqlite3_column_text(stmt_.get(), col);
+  auto size = util::size_from_int(::sqlite3_column_bytes(stmt_.get(), col));
+  if (!size.has_value())
+    throw std::logic_error{"unexpected negative amount of bytes in column"};
+  s = std::string{reinterpret_cast<char const*>(chs), *size};
+}
+
+auto row_reader::scan(int col, double& v) -> void
+{
+  if (::sqlite3_column_type(stmt_.get(), col) != SQLITE_FLOAT)
+    throw std::invalid_argument{"invalid type for scan"};
+  v = ::sqlite3_column_double(stmt_.get(), col);
+}
+
+auto row_reader::scan(int col, std::int64_t& v) -> void
+{
+  if (::sqlite3_column_type(stmt_.get(), col) != SQLITE_INTEGER)
+    throw std::invalid_argument{"invalid type for scan"};
+  v = ::sqlite3_column_int64(stmt_.get(), col);
+}
+
+auto row_reader::next() -> bool
+{
+  ::sqlite3* dbc = ::sqlite3_db_handle(stmt_.get());
+  return do_guarded(
+      dbc,
+      [&](auto const& guard) -> bool
+      {
+        auto const s = ::sqlite3_step(stmt_.get());
+        if (s == SQLITE_ROW)
+          return true;
+        if (s == SQLITE_DONE)
+          return false;
+        throw error{guard, s, dbc};
+      });
+}
+
+binder::binder(statement& stmt) : stmt_{stmt} {}
+
+auto binder::text(std::string const& param_name, std::string_view str) -> void
+{
+  int const i = ::sqlite3_bind_parameter_index(stmt_.get(), param_name.c_str());
+  if (i == 0)
+    throw std::invalid_argument{std::format(
+        "bind: no parameter with name {} found", param_name)};
+  auto str_size = util::int_from_size(str.size());
+  if (!str_size.has_value())
+    throw std::invalid_argument{"bind: provided text is too long"};
+  if (auto s = ::sqlite3_bind_text(
+          stmt_.get(), i, str.data(), *str_size, SQLITE_TRANSIENT);
+      s != SQLITE_OK)
+  {
+    throw error{s};
+  }
+}
+
+auto binder::noop(binder&) -> void {}
+
+connection::connection(::sqlite3* dbc)
+  : dbc_{dbc}, mut_{::sqlite3_db_mutex(dbc)}
+{
+}
+
+connection::connection(connection const&) = delete;
+connection::connection(connection&& c) noexcept
+{
+  dbc_ = c.dbc_;
+  mut_ = c.mut_;
+  c.dbc_ = nullptr;
+  c.mut_ = nullptr;
+}
+
+auto connection::query(
+    std::string const& sql, std::function<void(binder&)> const& bf)
+    -> row_reader
+{
+  ::sqlite3_stmt* pstmt = nullptr;
+  char const* sql_tail = nullptr;
+  auto sql_size = util::int_from_size(sql.size());
+  if (!sql_size.has_value() || *sql_size >= std::numeric_limits<int>::max() - 1)
+    throw std::invalid_argument{"provided input text too large"};
+  do_guarded(
+      mut_,
+      [&](auto const& guard) -> void
+      {
+        if (auto s = ::sqlite3_prepare_v2(
+                dbc_, sql.data(), *sql_size + 1, &pstmt, &sql_tail);
+            s != SQLITE_OK)
+        {
+          if (pstmt != nullptr)
+          {
+            // Use contract_assert when having a compiler with
+            // contracts available
+            ::sqlite3_finalize(pstmt);
+            throw std::logic_error{
+              "expected stmt to be null after failed preparation"
+            };
+          }
+          throw error{guard, s, dbc_};
+        }
+      });
+  if (!pstmt)
+    throw std::invalid_argument{"provided input text contains no SQL"};
+  auto stmt = statement{pstmt};
+  if (sql_tail && std::strlen(sql_tail) > 0)
+    throw std::invalid_argument{
+      "provided input text contains more than one SQL statement"
+    };
+  auto b = binder{stmt};
+  bf(b);
+  return row_reader{std::move(stmt)};
+}
+
+auto connection::exec(
+    std::string const& sql, std::function<void(binder&)> const& bf) -> void
+{
+  auto reader = query(sql, bf);
+  while (reader.next())
+    ;
+}
+
+connection::~connection()
+{
+  std::ignore = ::sqlite3_close(std::exchange(dbc_, nullptr));
+}
+
+auto open(std::string const& filename) -> connection
+{
+  ::sqlite3* dbc = nullptr;
+  auto s = ::sqlite3_open_v2(
+      filename.c_str(), &dbc,
+      SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE | SQLITE_OPEN_FULLMUTEX
+          | SQLITE_OPEN_EXRESCODE,
+      nullptr);
+  if (s != SQLITE_OK)
+  {
+    if (dbc)
+    {
+      do_guarded(
+          dbc, [&](auto const& guard) -> void { throw error{guard, s, dbc}; });
+    }
+    else
+    {
+      throw error{s};
+    }
+  }
+  return connection{dbc};
+}
+
+} // namespace routemon::sqlite3