Snap for 11566117 from 646563934a3e2ee26f50171f94d95173a1662e2c to sdk-releaseplatform-tools-35.0.1

Change-Id: Iec629b181a2c6905754a4c340e334884e13fd3b4

1 files changed, 71 insertions, 0 deletions

diff --git a/pw_allocator/public/pw_allocator/allocator_metric_proxy.h b/pw_allocator/public/pw_allocator/allocator_metric_proxy.h
new file mode 100644
index 000000000..b4cc3a561
--- /dev/null
+++ b/pw_allocator/public/pw_allocator/allocator_metric_proxy.h
@@ -0,0 +1,71 @@
+// Copyright 2023 The Pigweed Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may not
+// use this file except in compliance with the License. You may obtain a copy of
+// the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations under
+// the License.
+#pragma once
+
+#include <cstddef>
+
+#include "pw_allocator/allocator.h"
+#include "pw_metric/metric.h"
+#include "pw_status/status.h"
+
+namespace pw::allocator {
+
+/// Wraps an `Allocator` and records details of its usage.
+///
+/// In order for this object to record memory usage metrics correctly, all calls
+/// to, e.g., `Allocate`, `Deallocate`, etc. must be made through it and not the
+/// allocator it wraps.
+///
+/// As a rule, the wrapped allocator is always invoked before any conditions are
+/// asserted by this class, with the exception of checking that a wrapped
+/// allocator has been set via `Initialize`. This allows the wrapped allocator
+/// to issue a more detailed error in case of misuse.
+class AllocatorMetricProxy : public Allocator {
+ public:
+  constexpr explicit AllocatorMetricProxy(metric::Token token)
+      : memusage_(token) {}
+
+  /// Sets the wrapped allocator.
+  ///
+  /// This must be called exactly once and before any other method.
+  ///
+  /// @param[in]  allocator   The allocator to wrap and record.
+  void Initialize(Allocator& allocator);
+
+  metric::Group& memusage() { return memusage_; }
+  size_t used() const { return used_.value(); }
+  size_t peak() const { return peak_.value(); }
+  size_t count() const { return count_.value(); }
+
+ private:
+  /// @copydoc Allocator::Query
+  Status DoQuery(const void* ptr, Layout layout) const override;
+
+  /// @copydoc Allocator::Allocate
+  void* DoAllocate(Layout layout) override;
+
+  /// @copydoc Allocator::Deallocate
+  void DoDeallocate(void* ptr, Layout layout) override;
+
+  /// @copydoc Allocator::Resize
+  bool DoResize(void* ptr, Layout layout, size_t new_size) override;
+
+  metric::Group memusage_;
+  Allocator* allocator_ = nullptr;
+  PW_METRIC(used_, "used", 0U);
+  PW_METRIC(peak_, "peak", 0U);
+  PW_METRIC(count_, "count", 0U);
+};
+
+}  // namespace pw::allocator