dotscope 0.6.0

A high-performance, cross-platform framework for analyzing and reverse engineering .NET PE executables
Documentation 
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//! `MethodDebugInformation` table loader implementation
//!
//! Provides the [`MethodDebugInformationLoader`] implementation for loading method debugging
//! metadata from the Portable PDB `MethodDebugInformation` table (0x31). This loader is responsible
//! for processing debugging information that maps IL instructions to source code locations,
//! essential for providing step-through debugging capabilities.
//!
//! # Table Structure
//!
//! The `MethodDebugInformation` table contains debugging information for methods:
//! - **Document**: Coded index reference to the source document
//! - **`SequencePoints`**: Blob heap reference containing encoded sequence point data
//!
//! # Loading Process
//!
//! The loader processes method debug information entries in parallel, resolving heap references
//! and storing the complete debugging metadata in the loader context for use by debugging tools
//! and runtime environments.
//!
//! # Reference
//! * [Portable PDB Format - MethodDebugInformation Table](https://github.com/dotnet/core/blob/main/Documentation/diagnostics/portable_pdb.md#methoddebuginformation-table-0x31)

use crate::{
    metadata::{
        diagnostics::DiagnosticCategory,
        loader::{LoaderContext, MetadataLoader},
        tables::{MethodDebugInformationRaw, TableId},
    },
    Result,
};

/// Loader for the `MethodDebugInformation` metadata table
///
/// Implements [`MetadataLoader`] to process the `MethodDebugInformation` table (0x31)
/// which contains debugging information for methods in Portable PDB format. This loader
/// handles the conversion from raw binary data to structured debugging metadata that
/// can be used by development tools and debuggers.
///
/// # Processing Strategy
///
/// The loader uses parallel processing to efficiently handle large numbers of method
/// debug information entries, resolving heap references and building the complete
/// debugging metadata map for quick runtime access.
///
/// # Dependencies
///
/// This loader has no dependencies on other metadata tables, as it only references
/// heap data and coded indices that are resolved during the loading process.
///
/// # Reference
/// * [Portable PDB Format - `MethodDebugInformation` Table](https://github.com/dotnet/core/blob/main/Documentation/diagnostics/portable_pdb.md#methoddebuginformation-table-0x31)
pub struct MethodDebugInformationLoader;

impl MetadataLoader for MethodDebugInformationLoader {
    fn load(&self, context: &LoaderContext) -> Result<()> {
        let (Some(header), Some(blob)) = (context.meta, context.blobs) else {
            return Ok(());
        };
        let Some(table) = header.table::<MethodDebugInformationRaw>() else {
            return Ok(());
        };

        table.par_iter().try_for_each(|row| {
            let token_msg = || format!("method debug info 0x{:08x}", row.token.value());

            let Some(method_debug_info) =
                context.handle_result(row.to_owned(blob), DiagnosticCategory::Method, token_msg)?
            else {
                return Ok(());
            };

            context
                .method_debug_information
                .insert(method_debug_info.token, method_debug_info);
            Ok(())
        })
    }

    fn table_id(&self) -> Option<TableId> {
        Some(TableId::MethodDebugInformation)
    }

    fn dependencies(&self) -> &'static [TableId] {
        &[]
    }
}