feat: Add PrefixTree and RegisterHandler to support TDFA simulation.

[SharafMohamed]

Description

• Add PrefixTreeNode and PrefixTree classes to maintain a prefix tree representation of the registers. One tree represents all registers.
• Add Register class which tracks an index in the prefix tree. The vector of positions represented by a register can be obtained by going to its index in the prefix tree and traversing in reverse to the root.
• Add RegisterHandle class which maintains a vector of registers, as well as the prefix tree. This class handle the set, copy, append, and get operators.

Validation performed

• Unit-tests added for every new class.

Summary by CodeRabbit

• New Features

  • Introduced a new prefix tree data structure for managing tag positions.
  • Added a register management system for handling tag locations associated with regex.
  • Enhanced error handling for out-of-bounds access in both PrefixTree and RegisterHandler.
  • Implemented a method to retrieve reversed positions in the prefix tree.
  • Updated build configuration to include new source files and libraries for improved functionality.

• Tests

  • Added comprehensive unit tests for the PrefixTree and RegisterHandler classes to validate functionality and error handling.

[coderabbitai]

Actionable comments posted: 0

🧹 Outside diff range and nitpick comments (2)

src/log_surgeon/finite_automata/PrefixTree.hpp (2)

12-12: Fix typo in documentation

"posiiton" should be "position".

---

65-65: Simplify boolean expression

The expression false == m_parent_node_id.has_value() can be simplified.

-        [[nodiscard]] auto is_root() const -> bool { return false == m_parent_node_id.has_value(); }
+        [[nodiscard]] auto is_root() const -> bool { return !m_parent_node_id.has_value(); }

📜 Review details

Configuration used: CodeRabbit UI
Review profile: CHILL

📥 Commits

Reviewing files that changed from the base of the PR and between f651a24 and 1f66918.

📒 Files selected for processing (3)

• src/log_surgeon/finite_automata/PrefixTree.hpp (1 hunks)
• tests/test-prefix-tree.cpp (1 hunks)
• tests/test-register-handler.cpp (1 hunks)

🚧 Files skipped from review as they are similar to previous changes (2)

• tests/test-prefix-tree.cpp
• tests/test-register-handler.cpp

🧰 Additional context used

📓 Learnings (1)

src/log_surgeon/finite_automata/PrefixTree.hpp (2)

Learnt from: SharafMohamed
PR: y-scope/log-surgeon#56
File: src/log_surgeon/finite_automata/PrefixTree.hpp:80-80
Timestamp: 2024-11-27T22:24:42.637Z
Learning: The method `get_reversed_positions` is implemented in `src/log_surgeon/finite_automata/PrefixTree.cpp`.

Learnt from: SharafMohamed
PR: y-scope/log-surgeon#56
File: src/log_surgeon/finite_automata/PrefixTree.cpp:0-0
Timestamp: 2024-12-04T11:20:27.990Z
Learning: In the `PrefixTree` implementation in `src/log_surgeon/finite_automata/PrefixTree.cpp`, the root node serves as a common placeholder for all paths, and its position should be ignored in methods like `get_reversed_positions`.

🔇 Additional comments (3)

src/log_surgeon/finite_automata/PrefixTree.hpp (3)

22-25: LGTM! Well-defined types and constants

Good use of type aliases and constants to improve code maintainability and readability.

---

80-80: LGTM! Clean implementation of tree storage

The vector-based storage is an efficient choice for this use case.

---

56-56: Verify implementation of get_reversed_positions

Let's verify the implementation matches the declaration.

✅ Verification successful

Implementation matches declaration and follows expected behavior

The implementation in PrefixTree.cpp correctly matches the declaration in the header file:

• Returns std::vector<position_t> as declared
• Takes node_id parameter and is marked const
• Implements proper bounds checking
• Correctly builds reversed positions by traversing from node to root

🏁 Scripts executed

The following scripts were executed for the analysis:

Script:

#!/bin/bash
# Description: Verify get_reversed_positions implementation matches declaration

# Search for the implementation
rg "get_reversed_positions.*const.*std::vector<position_t>" src/log_surgeon/finite_automata/PrefixTree.cpp -A 10

Length of output: 604

[coderabbitai]

Actionable comments posted: 0

🧹 Outside diff range and nitpick comments (4)

src/log_surgeon/finite_automata/RegisterHandler.hpp (1)

20-26: Add method documentation for public methods

Consider adding documentation for each public method to clarify:

• Parameters and their purpose
• Return values and their meaning
• Exceptions that may be thrown
• Any preconditions or postconditions

Example format:

/**
 * @brief Adds a new register to the handler
 * @param prefix_tree_parent_node_id Parent node ID in the prefix tree
 * @param position Position in the lexed string
 * @throw std::out_of_range if prefix_tree_parent_node_id is out of range
 */

Also applies to: 28-30, 32-34, 36-39, 41-44

src/log_surgeon/finite_automata/PrefixTree.hpp (3)

12-20: Add root node documentation

Consider adding a note about the root node's special characteristics:

• Its position is always -1
• It has no parent (std::nullopt)
• It serves as a common placeholder for all paths

Also applies to: 28-28

---

36-43: Consider reserving vector capacity

The insert method could benefit from reserving capacity in the vector to reduce reallocations, especially if you know the approximate number of nodes that will be inserted.

// In constructor
m_nodes.reserve(expected_size);

---

78-80: Consider making member variables const where appropriate

If m_parent_id never changes after construction, consider making it const:

-    std::optional<id_t> m_parent_id;
+    std::optional<id_t> const m_parent_id;

📜 Review details

Configuration used: CodeRabbit UI
Review profile: CHILL

📥 Commits

Reviewing files that changed from the base of the PR and between 1f66918 and ed70bd5.

📒 Files selected for processing (5)

• src/log_surgeon/finite_automata/PrefixTree.cpp (1 hunks)
• src/log_surgeon/finite_automata/PrefixTree.hpp (1 hunks)
• src/log_surgeon/finite_automata/RegisterHandler.hpp (1 hunks)
• tests/test-prefix-tree.cpp (1 hunks)
• tests/test-register-handler.cpp (1 hunks)

🚧 Files skipped from review as they are similar to previous changes (3)

• src/log_surgeon/finite_automata/PrefixTree.cpp
• tests/test-register-handler.cpp
• tests/test-prefix-tree.cpp

🧰 Additional context used

📓 Learnings (2)

src/log_surgeon/finite_automata/PrefixTree.hpp (2)

Learnt from: SharafMohamed
PR: y-scope/log-surgeon#56
File: src/log_surgeon/finite_automata/PrefixTree.hpp:80-80
Timestamp: 2024-11-27T22:24:42.637Z
Learning: The method `get_reversed_positions` is implemented in `src/log_surgeon/finite_automata/PrefixTree.cpp`.

Learnt from: SharafMohamed
PR: y-scope/log-surgeon#56
File: src/log_surgeon/finite_automata/PrefixTree.cpp:0-0
Timestamp: 2024-12-04T11:20:27.990Z
Learning: In the `PrefixTree` implementation in `src/log_surgeon/finite_automata/PrefixTree.cpp`, the root node serves as a common placeholder for all paths, and its position should be ignored in methods like `get_reversed_positions`.

src/log_surgeon/finite_automata/RegisterHandler.hpp (2)

Learnt from: SharafMohamed
PR: y-scope/log-surgeon#56
File: src/log_surgeon/finite_automata/RegisterHandler.hpp:0-0
Timestamp: 2024-11-27T22:25:35.608Z
Learning: In the `RegisterHandler` class in `src/log_surgeon/finite_automata/RegisterHandler.hpp`, the methods `add_register` and `append_position` rely on `emplace_back` and `m_prefix_tree.insert` to handle exceptions correctly and maintain consistent state without requiring additional exception handling.

Learnt from: SharafMohamed
PR: y-scope/log-surgeon#56
File: src/log_surgeon/finite_automata/RegisterHandler.hpp:0-0
Timestamp: 2024-11-27T21:56:13.425Z
Learning: In the `log_surgeon` project, header guards in C++ header files should include `_HPP` at the end to match the filename. For example, in `RegisterHandler.hpp`, the header guard should be `LOG_SURGEON_FINITE_AUTOMATA_REGISTER_HANDLER_HPP`.

[LinZhihao-723]

Last two comments before we merge

[LinZhihao-723]

For the PR title, how about:

feat: Add `PrefixTree` and `RegisterHandler` to support TDFA simulation.