Struct ConcurrentCodeGraph 

pub struct ConcurrentCodeGraph { /* private fields */ }

Thread-safe wrapper for CodeGraph with epoch versioning.

ConcurrentCodeGraph provides MVCC-style concurrency:

• Multiple readers can access the graph simultaneously
• Only one writer can hold the lock at a time
• Each write operation increments the epoch for cursor invalidation

Design

The wrapper uses parking_lot::RwLock for efficient locking:

• Fair scheduling prevents writer starvation
• No poisoning (unlike std::sync::RwLock)
• Faster lock/unlock operations

Usage

use sqry_core::graph::unified::concurrent::ConcurrentCodeGraph;

let graph = ConcurrentCodeGraph::new();

// Read access (multiple readers allowed)
{
    let guard = graph.read();
    let _nodes = guard.nodes();
}

// Write access (exclusive)
{
    let mut guard = graph.write();
    let _nodes = guard.nodes_mut();
}

// Snapshot for long queries
let snapshot = graph.snapshot();

Implementations

impl ConcurrentCodeGraph

pub fn new() -> Self

Creates a new empty ConcurrentCodeGraph.

pub fn from_graph(graph: CodeGraph) -> Self

Creates a ConcurrentCodeGraph from an existing CodeGraph.

pub fn read(&self) -> RwLockReadGuard<'_, CodeGraph>

Acquires a read lock on the graph.

Multiple readers can hold the lock simultaneously. This does not increment the epoch.

pub fn write(&self) -> RwLockWriteGuard<'_, CodeGraph>

Acquires a write lock on the graph.

Only one writer can hold the lock at a time. This increments the global epoch counter.

pub fn epoch(&self) -> u64

Returns the current global epoch.

This can be used to detect if the graph has been modified since a previous operation (cursor invalidation).

pub fn snapshot(&self) -> GraphSnapshot

Creates a cheap snapshot of the graph.

This acquires a brief read lock to clone the Arc references. The snapshot is isolated from future mutations.

pub fn try_read(&self) -> Option<RwLockReadGuard<'_, CodeGraph>>

Attempts to acquire a read lock without blocking.

Returns None if the lock is currently held exclusively.

pub fn try_write(&self) -> Option<RwLockWriteGuard<'_, CodeGraph>>

Attempts to acquire a write lock without blocking.

Returns None if the lock is currently held by another thread. If successful, increments the epoch.

Trait Implementations

impl Debug for ConcurrentCodeGraph

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for ConcurrentCodeGraph

fn default() -> Self

Returns the “default value” for a type.