sqlitegraph 2.0.7

//! String Rollback Operations
//!
//! This module provides rollback operations for string-related WAL records:
//! - StringInsert: Limited implementation (strings remain in table due to deduplication)

use super::super::RollbackSystem;
use crate::backend::native::v2::wal::recovery::errors::RecoveryError;
use crate::debug::debug_log;

/// Rollback string insertion
///
/// String rollback is complex due to deduplication in the string table.
/// Multiple WAL records might reference the same string, so we can't
/// simply remove it from the table without reference counting.
///
/// Current implementation uses a logging-based approach where strings
/// remain in the table for consistency. Future implementation could use
/// reference counting.
pub fn rollback_string_insert(
    system: &RollbackSystem,
    _string_id: u64,
    _string_value: &str,
) -> Result<(), RecoveryError> {
    debug_log!(
        "Rolling back string insert: id={}, value='{}'",
        string_id,
        string_value
    );

    // String rollback is complex due to deduplication in the string table
    // Multiple WAL records might reference the same string, so we can't
    // simply remove it from the table without reference counting.

    // For now, implement a simple logging-based rollback:
    // 1. Log that we're rolling back the string insert
    // 2. Note that the string remains in the table for consistency
    // 3. Future implementation could use reference counting

    let _current_string_count = {
        let string_table_guard = system.string_table().lock().map_err(|e| {
            RecoveryError::replay_failure(format!("Failed to lock string table: {}", e))
        })?;

        string_table_guard.len()
    };

    debug_log!(
        "String table currently has {} strings",
        current_string_count
    );
    debug_log!(
        "String '{}' remains in table due to deduplication complexity",
        string_value
    );

    // In a production implementation with reference counting:
    // 1. Decrease reference count for the string
    // 2. If reference count reaches zero, remove from table
    // 3. Handle edge cases for shared strings

    // Current limitation: strings added during replay remain in table
    // This is generally safe as strings are small and deduplication
    // prevents excessive memory usage.

    debug_log!("String insert rollback completed (limited implementation)");
    Ok(())
}