From 160aba6258e1979ef85d66b2c27c33f6f28a7e38 Mon Sep 17 00:00:00 2001
From: Daniel Schadt <kingdread@gmx.de>
Date: Tue, 17 Jan 2023 23:06:54 +0100
Subject: factor out saving logic

Since we want to support SQLite at some point, it makes sense to have
the exact storage method abstracted away.
---
 src/renderer.rs | 42 +++++++++++++++++++-----------------------
 1 file changed, 19 insertions(+), 23 deletions(-)

(limited to 'src/renderer.rs')

diff --git a/src/renderer.rs b/src/renderer.rs
index bb33ddc..4840e73 100644
--- a/src/renderer.rs
+++ b/src/renderer.rs
@@ -1,9 +1,6 @@
-use std::{fs, path::Path, thread};
+use std::thread;
 
-use color_eyre::{
-    eyre::{bail, Result},
-    Report,
-};
+use color_eyre::{eyre::Result, Report};
 use image::{ImageBuffer, Luma, Pixel, RgbaImage};
 use nalgebra::{vector, Vector2};
 use rayon::iter::ParallelIterator;
@@ -13,6 +10,13 @@ use super::{
     layer::{self, TileLayer},
 };
 
+#[derive(Debug, Clone)]
+pub struct RenderedTile {
+    pub x: u64,
+    pub y: u64,
+    pub data: Vec<u8>,
+}
+
 pub type HeatCounter = TileLayer<Luma<u8>>;
 
 fn render_circle<P: Pixel>(layer: &mut TileLayer<P>, center: (u64, u64), radius: u64, pixel: P) {
@@ -135,32 +139,21 @@ fn colorize_tile(tile: &ImageBuffer<Luma<u8>, Vec<u8>>, max: u32) -> RgbaImage {
 /// rendering the next one.
 ///
 /// This has a way lower memory usage than [`colorize_heatcounter`].
-pub fn lazy_colorization<P: AsRef<Path>, F: Fn(usize) + Send + Sync>(
+pub fn lazy_colorization<F: FnMut(RenderedTile) -> Result<()> + Send + Sync>(
     layer: HeatCounter,
-    base_dir: P,
-    progress_callback: F,
+    mut save_callback: F,
 ) -> Result<()> {
-    let base_dir = base_dir.as_ref();
     let max = layer.pixels().map(|l| l.0[0]).max().unwrap_or_default();
     if max == 0 {
         return Ok(());
     }
 
-    type Job = (u64, u64, Vec<u8>);
-    let (tx, rx) = crossbeam_channel::bounded::<Job>(30);
+    let (tx, rx) = crossbeam_channel::bounded::<RenderedTile>(30);
 
     thread::scope(|s| {
         let saver = s.spawn(move || loop {
-            let Ok((tile_x, tile_y, data)) = rx.recv() else { return Ok(()) };
-            let folder = base_dir.join(tile_x.to_string());
-            let metadata = folder.metadata();
-            match metadata {
-                Err(_) => fs::create_dir(&folder)?,
-                Ok(m) if !m.is_dir() => bail!("Output path is not a directory"),
-                _ => {}
-            }
-            let file = folder.join(format!("{tile_y}.png"));
-            fs::write(file, data)?;
+            let Ok(tile) = rx.recv() else { return Ok::<_, Report>(()) };
+            save_callback(tile)?;
         });
 
         layer
@@ -168,8 +161,11 @@ pub fn lazy_colorization<P: AsRef<Path>, F: Fn(usize) + Send + Sync>(
             .try_for_each_with(tx, |tx, (tile_x, tile_y, tile)| {
                 let colorized = colorize_tile(&tile, max.into());
                 let data = layer::compress_png_as_bytes(&colorized)?;
-                tx.send((tile_x, tile_y, data))?;
-                progress_callback(1);
+                tx.send(RenderedTile {
+                    x: tile_x,
+                    y: tile_y,
+                    data,
+                })?;
                 Ok::<(), Report>(())
             })?;
 
-- 
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