display memory useage statistics when creating delta

Author: djugei

client/Cargo.toml

@@ -30,10 +30,11 @@ command-rusage = "1.0.1"
 ruma-headers = {path = "../ruma-headers"}
 flate2 = { version = "*" }
 libalpm-rs = "*"
+memory-stats = { version = "*", optional = true }
 
 [[bin]]
 name = "deltaclient"
 
 [features]
 default = ["diff"]
-diff = []
+diff = ["dep:memory-stats"]

client/src/main.rs

@@ -482,17 +482,33 @@ impl<T, E> ResultSwap<T, E> for Result<T, E> {
 
 #[cfg(feature = "diff")]
 fn gen_delta(orig: &Path, new: &Path, patch: &Path) -> Result<(), std::io::Error> {
+    use std::io::Read;
+
     let orig = OpenOptions::new().read(true).open(orig).unwrap();
-    let mut orig = zstd::Decoder::new(orig)?;
+    let mut origb = Vec::new();
+    zstd::Decoder::new(orig)?.read_to_end(&mut origb)?;
+    let mut origb = Cursor::new(origb);
+
     let new = OpenOptions::new().read(true).open(new).unwrap();
-    let mut new = zstd::Decoder::new(new)?;
+    let mut newb = Vec::new();
+    zstd::Decoder::new(new)?.read_to_end(&mut newb)?;
+    let mut newb = Cursor::new(newb);
 
     let patch = OpenOptions::new().write(true).create(true).open(patch).unwrap();
     let mut patch = zstd::Encoder::new(patch, 22)?;
 
-    ddelta::generate_chunked(&mut orig, &mut new, &mut patch, None, |p| debug!("{p:?}")).unwrap();
+    let before = memory_stats::memory_stats().unwrap().physical_mem;
+    let mut max = before;
+    ddelta::generate_chunked(&mut origb, &mut newb, &mut patch, None, |p| {
+        debug!("{p:?}");
+        max = max.max(memory_stats::memory_stats().unwrap().physical_mem)
+    })
+    .unwrap();
     patch.do_finish()?;
 
+    debug!("initial memory usage: {before}");
+    debug!("maximum memory usage: {max}");
+    debug!("origb: {}, newb: {}", origb.into_inner().len(), newb.into_inner().len());
     Ok(())
 }