minedmap: separate collection for region list from preprocessing

Preparation for parallel processing, as well as a fix for regions
missing from later steps when the initial processing failed (rather than
using the processed data from a previous run).

src/bin/minedmap/common.rs

@@ -85,6 +85,11 @@ impl Config {
 		}
 	}
 
+	pub fn region_path(&self, coords: TileCoords) -> PathBuf {
+		let filename = coord_filename(coords, "mca");
+		[&self.region_dir, Path::new(&filename)].iter().collect()
+	}
+
 	pub fn processed_path(&self, coords: TileCoords) -> PathBuf {
 		let filename = coord_filename(coords, "bin");
 		[&self.processed_dir, Path::new(&filename)].iter().collect()

src/bin/minedmap/main.rs

@@ -10,7 +10,7 @@ use std::path::PathBuf;
 use anyhow::Result;
 use clap::Parser;
 
-use common::{Config, TileCoords};
+use common::Config;
 use metadata_writer::MetadataWriter;
 use region_processor::RegionProcessor;
 use tile_mipmapper::TileMipmapper;
@@ -28,11 +28,7 @@ fn main() -> Result<()> {
 	let args = Args::parse();
 	let config = Config::new(args);
 
-	let mut regions = RegionProcessor::new(&config).run()?;
-
-	// Sort regions in a zig-zag pattern to optimize cache usage
-	regions.sort_unstable_by_key(|&TileCoords { x, z }| (x, if x % 2 == 0 { z } else { -z }));
-
+	let regions = RegionProcessor::new(&config).run()?;
 	TileRenderer::new(&config).run(&regions)?;
 	let tiles = TileMipmapper::new(&config).run(&regions)?;
 	MetadataWriter::new(&config).run(tiles)?;

src/bin/minedmap/region_processor.rs

@@ -1,4 +1,4 @@
-use std::{path::Path, time::SystemTime};
+use std::{ffi::OsStr, path::Path, time::SystemTime};
 
 use anyhow::{Context, Result};
 
@@ -16,9 +16,8 @@ use minedmap::{
 use super::common::*;
 
 /// Parses a filename in the format r.X.Z.mca into the contained X and Z values
-fn parse_region_filename(path: &Path) -> Option<TileCoords> {
-	let file_name = path.file_name()?.to_str()?;
-	let parts: Vec<_> = file_name.split('.').collect();
+fn parse_region_filename(file_name: &OsStr) -> Option<TileCoords> {
+	let parts: Vec<_> = file_name.to_str()?.split('.').collect();
 	let &["r", x, z, "mca"] = parts.as_slice() else {
 		return None;
 	};
@@ -45,6 +44,29 @@ impl<'a> RegionProcessor<'a> {
 		}
 	}
 
+	fn collect_regions(&self) -> Result<Vec<TileCoords>> {
+		Ok(self
+			.config
+			.region_dir
+			.read_dir()
+			.with_context(|| {
+				format!(
+					"Failed to read directory {}",
+					self.config.region_dir.display()
+				)
+			})?
+			.filter_map(|entry| entry.ok())
+			.filter(|entry| {
+				// We are only interested in regular files
+				matches!(
+					entry.file_type().map(|file_type| file_type.is_file()),
+					Ok(true)
+				)
+			})
+			.filter_map(|entry| parse_region_filename(&entry.file_name()))
+			.collect())
+	}
+
 	/// Processes a single chunk
 	fn process_chunk(
 		&self,
@@ -91,13 +113,14 @@ impl<'a> RegionProcessor<'a> {
 	}
 
 	/// Processes a single region file
-	fn process_region(&self, path: &Path, coords: TileCoords) -> Result<()> {
+	fn process_region(&self, coords: TileCoords) -> Result<()> {
 		const N: u32 = (BLOCKS_PER_CHUNK * CHUNKS_PER_REGION) as u32;
 
 		let mut processed_region = ProcessedRegion::default();
 		let mut lightmap = image::GrayAlphaImage::new(N, N);
 
-		let input_timestamp = fs::modified_timestamp(path)?;
+		let path = self.config.region_path(coords);
+		let input_timestamp = fs::modified_timestamp(&path)?;
 
 		let output_path = self.config.processed_path(coords);
 		let output_timestamp = fs::read_timestamp(&output_path, FILE_META_VERSION);
@@ -152,41 +175,20 @@ impl<'a> RegionProcessor<'a> {
 	///
 	/// Returns a list of the coordinates of all processed regions
 	pub fn run(self) -> Result<Vec<TileCoords>> {
-		let read_dir = self.config.region_dir.read_dir().with_context(|| {
-			format!(
-				"Failed to read directory {}",
-				self.config.region_dir.display()
-			)
-		})?;
+		let mut regions = self.collect_regions()?;
+
+		// Sort regions in a zig-zag pattern to optimize cache usage
+		regions.sort_unstable_by_key(|&TileCoords { x, z }| (x, if x % 2 == 0 { z } else { -z }));
 
 		fs::create_dir_all(&self.config.processed_dir)?;
 		fs::create_dir_all(&self.config.tile_dir(TileKind::Lightmap, 0))?;
 
-		let mut ret = Vec::new();
-
-		for entry in read_dir.filter_map(|entry| entry.ok()).filter(|entry| {
-			// We are only interested in regular files
-			entry
-				.file_type()
-				.map(|file_type| file_type.is_file())
-				.unwrap_or_default()
-		}) {
-			let path = entry.path();
-			let Some(coords) = parse_region_filename(&path) else {
-				continue;
-			};
-
-			if let Err(err) = self.process_region(&path, coords) {
-				eprintln!(
-					"Failed to process region {}: {:?}",
-					path.file_name().unwrap_or_default().to_string_lossy(),
-					err,
-				);
-			}
-
-			ret.push(coords);
-		}
-
-		Ok(ret)
+		for &coords in &regions {
+			if let Err(err) = self.process_region(coords) {
+				eprintln!("Failed to process region {:?}: {:?}", coords, err);
+			}
+		}
+
+		Ok(regions)
 	}
 }