From 60771382920b9178ef60d0f20c3c898a52f274de Mon Sep 17 00:00:00 2001
From: Matthias Schiffer <mschiffer@universe-factory.net>
Date: Sun, 30 Jul 2023 21:48:58 +0200
Subject: [PATCH] Add version field to file metadata

---
 src/bin/minedmap/common.rs           |  5 ++++-
 src/bin/minedmap/region_processor.rs |  3 ++-
 src/bin/minedmap/tile_mipmapper.rs   |  2 +-
 src/bin/minedmap/tile_renderer.rs    |  2 +-
 src/io/fs.rs                         | 13 +++++++++++--
 src/io/storage.rs                    |  9 +++++++--
 6 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/src/bin/minedmap/common.rs b/src/bin/minedmap/common.rs
index 4aed1c0..a108e8d 100644
--- a/src/bin/minedmap/common.rs
+++ b/src/bin/minedmap/common.rs
@@ -6,7 +6,10 @@ use std::{
 
 use serde::{Deserialize, Serialize};
 
-use minedmap::{types::*, world::layer};
+use minedmap::{io::fs::FileMetaVersion, types::*, world::layer};
+
+// Increase to force regeneration of all output files
+pub const FILE_META_VERSION: FileMetaVersion = FileMetaVersion(0);
 
 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
 pub struct TileCoords {
diff --git a/src/bin/minedmap/region_processor.rs b/src/bin/minedmap/region_processor.rs
index 2081785..d20f82b 100644
--- a/src/bin/minedmap/region_processor.rs
+++ b/src/bin/minedmap/region_processor.rs
@@ -72,7 +72,7 @@ impl<'a> RegionProcessor<'a> {
 		timestamp: SystemTime,
 	) -> Result<()> {
 		let output_path = self.config.processed_path(coords);
-		storage::write(&output_path, processed_region, timestamp)
+		storage::write(&output_path, processed_region, FILE_META_VERSION, timestamp)
 	}
 
 	fn save_lightmap(
@@ -83,6 +83,7 @@ impl<'a> RegionProcessor<'a> {
 	) -> Result<()> {
 		fs::create_with_timestamp(
 			&self.config.tile_path(TileKind::Lightmap, 0, coords),
+			FILE_META_VERSION,
 			timestamp,
 			|file| {
 				lightmap
diff --git a/src/bin/minedmap/tile_mipmapper.rs b/src/bin/minedmap/tile_mipmapper.rs
index 51eebd9..22b942d 100644
--- a/src/bin/minedmap/tile_mipmapper.rs
+++ b/src/bin/minedmap/tile_mipmapper.rs
@@ -109,7 +109,7 @@ impl<'a> TileMipmapper<'a> {
 			);
 		}
 
-		fs::create_with_timestamp(&output_path, timestamp, |file| {
+		fs::create_with_timestamp(&output_path, FILE_META_VERSION, timestamp, |file| {
 			image
 				.write_to(file, image::ImageFormat::Png)
 				.context("Failed to save image")
diff --git a/src/bin/minedmap/tile_renderer.rs b/src/bin/minedmap/tile_renderer.rs
index 0b804c8..0e91054 100644
--- a/src/bin/minedmap/tile_renderer.rs
+++ b/src/bin/minedmap/tile_renderer.rs
@@ -78,7 +78,7 @@ impl<'a> TileRenderer<'a> {
 		let mut image = image::RgbaImage::new(N, N);
 		Self::render_region(&mut image, &region);
 
-		fs::create_with_timestamp(&output_path, timestamp, |file| {
+		fs::create_with_timestamp(&output_path, FILE_META_VERSION, timestamp, |file| {
 			image
 				.write_to(file, image::ImageFormat::Png)
 				.context("Failed to save image")
diff --git a/src/io/fs.rs b/src/io/fs.rs
index 0cb2a4d..dfb2e78 100644
--- a/src/io/fs.rs
+++ b/src/io/fs.rs
@@ -8,8 +8,12 @@ use std::{
 use anyhow::{Context, Ok, Result};
 use serde::Serialize;
 
+#[derive(Debug, Clone, Copy, Serialize)]
+pub struct FileMetaVersion(pub u32);
+
 #[derive(Debug, Serialize)]
 struct FileMeta {
+	version: FileMetaVersion,
 	timestamp: SystemTime,
 }
 
@@ -111,7 +115,12 @@ pub fn modified_timestamp(path: &Path) -> Result<SystemTime> {
 		})
 }
 
-pub fn create_with_timestamp<T, F>(path: &Path, timestamp: SystemTime, f: F) -> Result<T>
+pub fn create_with_timestamp<T, F>(
+	path: &Path,
+	version: FileMetaVersion,
+	timestamp: SystemTime,
+	f: F,
+) -> Result<T>
 where
 	F: FnOnce(&mut BufWriter<File>) -> Result<T>,
 {
@@ -119,7 +128,7 @@ where
 
 	let meta_path = metafile_name(path);
 	create(&meta_path, |file| {
-		serde_json::to_writer(file, &FileMeta { timestamp })?;
+		serde_json::to_writer(file, &FileMeta { version, timestamp })?;
 		Ok(())
 	})?;
 
diff --git a/src/io/storage.rs b/src/io/storage.rs
index b889231..4ba6050 100644
--- a/src/io/storage.rs
+++ b/src/io/storage.rs
@@ -10,8 +10,13 @@ use serde::{de::DeserializeOwned, Serialize};
 
 use super::fs;
 
-pub fn write<T: Serialize>(path: &Path, value: &T, timestamp: SystemTime) -> Result<()> {
-	fs::create_with_timestamp(path, timestamp, |file| {
+pub fn write<T: Serialize>(
+	path: &Path,
+	value: &T,
+	version: fs::FileMetaVersion,
+	timestamp: SystemTime,
+) -> Result<()> {
+	fs::create_with_timestamp(path, version, timestamp, |file| {
 		let data = bincode::serialize(value)?;
 		let len = u32::try_from(data.len())?;
 		let compressed = zstd::bulk::compress(&data, 1)?;