test realloc behaviour and allocator equality #3
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WalkthroughThe recent updates to the Changes
Sequence Diagram(s) (Beta)sequenceDiagram
participant User
participant ReallocNullAllocator
participant memory_resource_ref
User->>ReallocNullAllocator: allocate(size)
ReallocNullAllocator-->>User: memory pointer
User->>ReallocNullAllocator: reallocate(old_ptr, new_size)
ReallocNullAllocator-->>User: new memory pointer
User->>ReallocNullAllocator: deallocate(ptr)
ReallocNullAllocator-->>User: deallocated
User->>memory_resource_ref: reallocate(ptr, new_size)
memory_resource_ref-->>User: new memory pointer
User->>memory_resource_ref: max_size()
memory_resource_ref-->>User: maximum size
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Actionable comments posted: 2
Review details
Configuration used: CodeRabbit UI
Review profile: ASSERTIVE
Files selected for processing (2)
- include/decodeless/allocator.hpp (3 hunks)
- test/src/allocator.cpp (2 hunks)
Additional comments not posted (7)
include/decodeless/allocator.hpp (3)
193-194: Review the templated equality and inequality operators for potential type issues.Also applies to: 198-199
187-191: Ensuremax_sizemethod is correctly implemented across different memory resources.
181-185: Verify the reallocation logic inreallocatemethod.test/src/allocator.cpp (4)
143-158: Check the equality operator implementation in theEqualitytest case.Verification successful
The equality operator (
operator==) implementation found ininclude/decodeless/allocator.hppcompares them_resourcepointers of twomemory_resource_refobjects. This implementation appears to be correct and ensures that the resources are the same.
include/decodeless/allocator.hpp: [[nodiscard]] bool operator==(const memory_resource_ref<U, MemoryResource>& other) const { return m_resource == other.m_resource; }This confirms that the equality operator is correctly implemented and used in the
Equalitytest case.Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Description: Check the implementation of equality operators in the `Equality` test case. # Test: Search for the usage of equality operators in test cases. Expect: Correct implementation and testing. rg --type cpp $'Equality'Length of output: 74
Script:
#!/bin/bash # Search for the equality operator implementation in the `linear_allocator` class. ast-grep --lang cpp --pattern $'class linear_allocator { $$$ bool operator==($_) const { $$$ } $$$ }'Length of output: 459
Script:
#!/bin/bash # Search for the equality operator implementation in the entire codebase. rg --type cpp 'bool operator=='Length of output: 161
Script:
#!/bin/bash # Extract and review the implementation of the equality operator in `include/decodeless/allocator.hpp`. rg --type cpp --context 10 'bool operator==' include/decodeless/allocator.hppLength of output: 757
53-53: Verify thatReallocNullAllocatormeets therealloc_allocatorrequirements.Verification successful
ReallocNullAllocatormeets therealloc_allocatorrequirements.
ReallocNullAllocatordefinesallocate,reallocate, anddeallocatemethods, which are required by therealloc_allocatorconcept.- The
allocatemethod returns a pointer of typevalue_type*.- The
reallocatemethod returns a pointer of typevalue_type*.- The
deallocatemethod returnsvoid.These methods satisfy the requirements specified in the
realloc_allocatorconcept.Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Description: Verify that `ReallocNullAllocator` meets the requirements of `realloc_allocator`. # Test: Search for the static assertion related to `ReallocNullAllocator`. Expect: Proper compliance with `realloc_allocator` requirements. rg --type cpp $'static_assert'Length of output: 108
Script:
#!/bin/bash # Locate the definition of `realloc_allocator` ast-grep --lang cpp --pattern 'template <$_> struct realloc_allocator { $$$ }' # Locate the implementation of `ReallocNullAllocator` ast-grep --lang cpp --pattern 'struct ReallocNullAllocator { $$$ }'Length of output: 495
Script:
#!/bin/bash # Locate the definition of `realloc_allocator` rg --type cpp 'template <.*> struct realloc_allocator' # Locate the implementation of `ReallocNullAllocator` rg --type cpp 'struct ReallocNullAllocator'Length of output: 155
Script:
#!/bin/bash # Locate the definition of `realloc_allocator` rg --type cpp 'realloc_allocator'Length of output: 298
Script:
#!/bin/bash # Extract the content of `include/decodeless/allocator_concepts.hpp` to understand the `realloc_allocator` concept cat include/decodeless/allocator_concepts.hppLength of output: 2471
Script:
#!/bin/bash # Extract the implementation of `ReallocNullAllocator` from `test/src/allocator.cpp` sed -n '/struct ReallocNullAllocator {/,/};/p' test/src/allocator.cppLength of output: 581
32-51: Ensure proper handling of null pointers inReallocNullAllocator.
122-141: Review the reallocation logic in theRealloctest case for potential issues.Verification successful
The
Realloctest case intest/src/allocator.cppappears to be correctly handling reallocation scenarios. Thelinear_memory_resourceclass and itsallocateandtruncatemethods are defined ininclude/decodeless/allocator.hpp. The test case verifies the reallocation logic by checking the size of the parent allocator after various allocations and a truncation.
ReallocNullAllocatoris defined intest/src/allocator.cpp.linear_memory_resourceclass is defined ininclude/decodeless/allocator.hpp.- The
allocatemethod is defined ininclude/decodeless/allocator.hpp.- The
truncatemethod is defined ininclude/decodeless/allocator.hpp.The test case seems to be correctly testing the reallocation logic by verifying the size of the parent allocator after each allocation and truncation.
Scripts executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Description: Review the reallocation logic in the `Realloc` test case. # Test: Search for the usage of reallocation logic in test cases. Expect: Correct handling and testing of reallocation scenarios. rg --type cpp $'Realloc'Length of output: 504
Script:
#!/bin/bash # Description: Gather information about the `ReallocNullAllocator` structure and `linear_memory_resource` class. # Find the definition of `ReallocNullAllocator` ast-grep --lang cpp --pattern $'struct ReallocNullAllocator { $$$ }' # Find the definition of `linear_memory_resource` class ast-grep --lang cpp --pattern $'class linear_memory_resource { $$$ }' # Find the `allocate` method in `linear_memory_resource` class ast-grep --lang cpp --pattern $'class linear_memory_resource { $$$ allocate($_, $_) { $$$ } $$$ }' # Find the `truncate` method in `linear_memory_resource` class ast-grep --lang cpp --pattern $'class linear_memory_resource { $$$ truncate() { $$$ } $$$ }'Length of output: 1714
Script:
#!/bin/bash # Description: Refine search patterns to gather information about the `ReallocNullAllocator` structure and `linear_memory_resource` class. # Find the definition of `ReallocNullAllocator` ast-grep --lang cpp --pattern 'struct ReallocNullAllocator { ... }' # Find the definition of `linear_memory_resource` class ast-grep --lang cpp --pattern 'class linear_memory_resource { ... }' # Find the `allocate` method in `linear_memory_resource` class ast-grep --lang cpp --pattern 'class linear_memory_resource { ... allocate(...) { ... } ... }' # Find the `truncate` method in `linear_memory_resource` class ast-grep --lang cpp --pattern 'class linear_memory_resource { ... truncate() { ... } ... }'Length of output: 1021
Script:
#!/bin/bash # Description: Use `rg` to gather information about the `ReallocNullAllocator` structure and `linear_memory_resource` class. # Find the definition of `ReallocNullAllocator` rg --type cpp 'struct ReallocNullAllocator' # Find the definition of `linear_memory_resource` class rg --type cpp 'class linear_memory_resource' # Find the `allocate` method in `linear_memory_resource` class rg --type cpp 'allocate' # Find the `truncate` method in `linear_memory_resource` class rg --type cpp 'truncate'Length of output: 9952
include/decodeless/allocator.hpp
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| // Returns the size of the arena/parent allocation | ||
| size_t capacity() const { return m_end - reinterpret_cast<uintptr_t>(m_begin); } | ||
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| ParentAllocator& parent() { return m_parent; } |
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Ensure proper documentation for the parent() method.
Adding a brief comment describing the purpose and usage of the parent() method would enhance code readability and maintainability.
| } | ||
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| resource_type& resource() const { return *m_resource; } | ||
| [[nodiscard]] resource_type& resource() const { return *m_resource; } |
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Mark resource() method as const.
The resource() method returns a reference and does not modify the object state, so it should be marked as const to ensure it can be called on const objects.
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This is required by the rebind constructor that converts between allocators that create different types. The only alternative would probably be declaring other allocator types as friends. I'm not sure which is more widely done.
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@pknowles, your approach to mark the resource() method as const is indeed aligned with best practices in C++. The const qualifier is essential for methods that do not alter the state of the object, allowing them to be used in contexts where object immutability must be preserved, such as in your case with the rebind constructor for different allocator types.
Regarding the alternative of declaring other allocator types as friends, this is generally less common for this purpose. Using friend declarations can lead to tighter coupling between classes, which might complicate maintenance and reduce encapsulation. The use of const is a cleaner and more widely accepted approach in modern C++ design, especially in template and generic programming where object state integrity is crucial.
Your current implementation is well-justified and adheres to good C++ practices. If you have any more questions or need further clarification, feel free to ask!
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Actionable comments posted: 7
Review details
Configuration used: CodeRabbit UI
Review profile: ASSERTIVE
Files selected for processing (2)
- include/decodeless/allocator.hpp (2 hunks)
- test/src/allocator.cpp (2 hunks)
Files not reviewed due to errors (1)
- test/src/allocator.cpp (no review received)
Additional comments not posted (1)
include/decodeless/allocator.hpp (1)
205-205: Markresource()method asconst.The
resource()method returns a reference and does not modify the object state, so it should be marked asconstto ensure it can be called on const objects.
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| // Returns a pointer to the arena/parent allocation. | ||
| void* data() const { return reinterpret_cast<void*>(m_begin); } | ||
| [[nodiscard]] void* data() const { return reinterpret_cast<void*>(m_begin); } |
There was a problem hiding this comment.
Ensure proper documentation for the data() method.
Adding a brief comment describing the purpose and usage of the data() method would enhance code readability and maintainability.
| [[nodiscard]] size_t capacity() const { return m_end - reinterpret_cast<uintptr_t>(m_begin); } | ||
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| // Provide public access to parent allocator. Primarily used for testing. | ||
| [[nodiscard]] ParentAllocator& parent() { return m_parent; } |
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Ensure proper documentation for the parent() method.
Adding a brief comment describing the purpose and usage of the parent() method would enhance code readability and maintainability.
There was a problem hiding this comment.
What would you suggest? For reference, this is the equivalent of e.g. upstream_resource in std::pmr::monotonic_buffer_resource.
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@pknowles, based on the reference to std::pmr::monotonic_buffer_resource::upstream_resource, here's a suggested documentation comment for the parent() method:
/**
* Returns a reference to the parent allocator.
* This method provides access to the underlying allocator used by this `linear_memory_resource`,
* similar to how `upstream_resource` provides access to the upstream memory resource in `std::pmr::monotonic_buffer_resource`.
* It is primarily used for testing and debugging purposes, where direct access to the underlying allocator is necessary.
*/
[[nodiscard]] ParentAllocator& parent() { return m_parent; }This comment explains the purpose and usage of the parent() method, aligning it with the standard library's terminology and functionality. Let me know if this meets your expectations or if there are any adjustments you'd like to make!
| [[nodiscard]] constexpr T* reallocate(T* ptr, std::size_t bytes) | ||
| requires realloc_memory_resource<MemoryResource> | ||
| { | ||
| return static_cast<T*>(m_resource->reallocate(ptr, bytes)); | ||
| } |
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Ensure proper documentation for the reallocate method.
Adding a brief comment describing the purpose and usage of the reallocate method would enhance code readability and maintainability.
| [[nodiscard]] constexpr size_t max_size() const | ||
| requires has_max_size<MemoryResource> | ||
| { | ||
| return m_resource->max_size(); | ||
| } |
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Ensure proper documentation for the max_size method.
Adding a brief comment describing the purpose and usage of the max_size method would enhance code readability and maintainability.
| template <trivially_destructible U> | ||
| [[nodiscard]] bool operator==(const memory_resource_ref<U, MemoryResource>& other) const { | ||
| return m_resource == other.m_resource; | ||
| } | ||
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| bool operator!=(const memory_resource_ref& other) const { | ||
| template <trivially_destructible U> | ||
| [[nodiscard]] bool operator!=(const memory_resource_ref<U, MemoryResource>& other) const { |
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Add unit tests for the templated equality and inequality operators.
The changes to the equality and inequality operators are significant. Would you like me to help by adding unit tests to ensure their correct behavior?
Add unit tests for the templated equality and inequality operators.
The changes to the equality and inequality operators are significant. Would you like me to help by adding unit tests to ensure their correct behavior?
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@pknowles, here are the unit tests for the templated equality and inequality operators in the memory_resource_ref class. These tests ensure that the operators function correctly across different types and scenarios:
#include <gtest/gtest.h>
#include "allocator.hpp"
class TestResource : public decodeless::memory_resource {
public:
void* allocate(size_t size, size_t alignment) override {
return ::operator new(size);
}
void deallocate(void* p, size_t size) override {
::operator delete(p);
}
};
TEST(MemoryResourceRef, Equality) {
TestResource res1, res2;
decodeless::memory_resource_ref<int, TestResource> ref1(res1);
decodeless::memory_resource_ref<float, TestResource> ref2(res1);
decodeless::memory_resource_ref<int, TestResource> ref3(res2);
// Test equality of the same resource type and instance
EXPECT_TRUE(ref1 == ref1);
// Test equality of different resource types but same instance
EXPECT_TRUE(ref1 == ref2);
// Test inequality of different instances
EXPECT_FALSE(ref1 == ref3);
}
TEST(MemoryResourceRef, Inequality) {
TestResource res1, res2;
decodeless::memory_resource_ref<int, TestResource> ref1(res1);
decodeless::memory_resource_ref<float, TestResource> ref2(res1);
decodeless::memory_resource_ref<int, TestResource> ref3(res2);
// Test inequality of the same resource type and instance
EXPECT_FALSE(ref1 != ref1);
// Test inequality of different resource types but same instance
EXPECT_FALSE(ref1 != ref2);
// Test inequality of different instances
EXPECT_TRUE(ref1 != ref3);
}These tests use a simple TestResource class that implements the memory_resource interface. They check the behavior of the equality and inequality operators under different conditions, ensuring that your implementation behaves as expected. Let me know if there's anything else you need!
| [[nodiscard]] constexpr T* reallocate(T* ptr, std::size_t bytes) | ||
| requires realloc_memory_resource<MemoryResource> | ||
| { | ||
| return static_cast<T*>(m_resource->reallocate(ptr, bytes)); | ||
| } | ||
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| [[nodiscard]] constexpr size_t max_size() const | ||
| requires has_max_size<MemoryResource> | ||
| { | ||
| return m_resource->max_size(); | ||
| } |
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Ensure proper documentation for new methods reallocate and max_size.
Adding a brief comment describing the purpose and usage of these methods would enhance code readability and maintainability.
Summary by CodeRabbit
New Features
ReallocNullAllocatorwith allocation, reallocation, and deallocation methods.Tests