[thin_metadata_{pack,unpak}] use anyhow in toplevel.

Cargo.lock

@@ -21,6 +21,11 @@ dependencies = [
  "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "anyhow"
+version = "1.0.31"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "arrayvec"
 version = "0.4.12"
@@ -380,6 +385,7 @@ dependencies = [
 name = "thinp"
 version = "0.1.0"
 dependencies = [
+ "anyhow 1.0.31 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "clap 2.33.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "crc32c 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -393,6 +399,25 @@ dependencies = [
  "quickcheck 0.9.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "quickcheck_macros 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "thiserror 1.0.20 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "thiserror"
+version = "1.0.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "thiserror-impl 1.0.20 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "1.0.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 1.0.18 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.30 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -456,6 +481,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum adler32 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "5d2e7343e7fc9de883d1b0341e0b13970f764c14101234857d2ddafa1cb1cac2"
 "checksum aho-corasick 0.7.10 (registry+https://github.com/rust-lang/crates.io-index)" = "8716408b8bc624ed7f65d223ddb9ac2d044c0547b6fa4b0d554f3a9540496ada"
 "checksum ansi_term 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ee49baf6cb617b853aa8d93bf420db2383fab46d314482ca2803b40d5fde979b"
+"checksum anyhow 1.0.31 (registry+https://github.com/rust-lang/crates.io-index)" = "85bb70cc08ec97ca5450e6eba421deeea5f172c0fc61f78b5357b2a8e8be195f"
 "checksum arrayvec 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)" = "cd9fd44efafa8690358b7408d253adf110036b88f55672a933f01d616ad9b1b9"
 "checksum atty 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)" = "d9b39be18770d11421cdb1b9947a45dd3f37e93092cbf377614828a319d5fee8"
 "checksum autocfg 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "f8aac770f1885fd7e387acedd76065302551364496e46b3dd00860b2f8359b9d"
@@ -501,6 +527,8 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum strsim 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "8ea5119cdb4c55b55d432abb513a0429384878c15dde60cc77b1c99de1a95a6a"
 "checksum syn 1.0.30 (registry+https://github.com/rust-lang/crates.io-index)" = "93a56fabc59dce20fe48b6c832cc249c713e7ed88fa28b0ee0a3bfcaae5fe4e2"
 "checksum textwrap 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d326610f408c7a4eb6f51c37c330e496b08506c9457c9d34287ecc38809fb060"
+"checksum thiserror 1.0.20 (registry+https://github.com/rust-lang/crates.io-index)" = "7dfdd070ccd8ccb78f4ad66bf1982dc37f620ef696c6b5028fe2ed83dd3d0d08"
+"checksum thiserror-impl 1.0.20 (registry+https://github.com/rust-lang/crates.io-index)" = "bd80fc12f73063ac132ac92aceea36734f04a1d93c1240c6944e23a3b8841793"
 "checksum thread_local 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "d40c6d1b69745a6ec6fb1ca717914848da4b44ae29d9b3080cbee91d72a69b14"
 "checksum unicode-width 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)" = "caaa9d531767d1ff2150b9332433f32a24622147e5ebb1f26409d5da67afd479"
 "checksum unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "826e7639553986605ec5979c7dd957c7895e93eabed50ab2ffa7f6128a75097c"

Cargo.toml

@@ -6,6 +6,7 @@ edition = "2018"
 license = "GPL3"
 
 [dependencies]
+anyhow = "1.0"
 byteorder = "1.3"
 clap = "2.33"
 crc32c = "0.4"
@@ -14,9 +15,10 @@ libc = "0.2.71"
 nix = "0.17"
 nom = "5.1"
 num_cpus = "1.13"
-rand = "0.7"
-num-traits = "0.2"
 num-derive = "0.3"
+num-traits = "0.2"
+rand = "0.7"
+thiserror = "1.0"
 
 [dev-dependencies]
 quickcheck = "0.9"

src/pack/node_encode.rs

@@ -1,3 +1,4 @@
+use thiserror::Error;
 use std::{io, io::Write};
 
 use nom::{bytes::complete::*, number::complete::*, IResult};
@@ -6,41 +7,27 @@ use crate::pack::vm::*;
 
 //-------------------------------------------
 
-#[derive(Debug)]
+#[derive(Error, Debug)]
 pub enum PackError {
+    #[error("Couldn't parse binary data")]
     ParseError,
-    IOError,
-}
 
-impl std::error::Error for PackError {}
+    #[error("Write error")]
+    WriteError { source: std::io::Error },
+}
 
 pub type PResult<T> = Result<T, PackError>;
 
 fn nom_to_pr<T>(r: IResult<&[u8], T>) -> PResult<(&[u8], T)> {
-    match r {
+    r.map_err(|_source| PackError::ParseError)
-        Ok(v) => Ok(v),
-        Err(_) => Err(PackError::ParseError),
-    }
 }
 
 fn io_to_pr<T>(r: io::Result<T>) -> PResult<T> {
-    match r {
+    r.map_err(|source| PackError::WriteError {source})
-        Ok(v) => Ok(v),
-        Err(_) => Err(PackError::IOError),
-    }
 }
 
 //-------------------------------------------
 
-impl std::fmt::Display for PackError {
-    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
-        match self {
-            PackError::ParseError => write!(f, "parse error"),
-            PackError::IOError => write!(f, "IO error"),
-        }
-    }
-}
-
 fn run64(i: &[u8], count: usize) -> IResult<&[u8], Vec<u64>> {
     let (i, ns) = nom::multi::many_m_n(count, count, le_u64)(i)?;
     Ok((i, ns))

src/pack/toplevel.rs

@@ -1,3 +1,4 @@
+use anyhow::{anyhow, Context, Result};
 use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
 
 use flate2::{read::ZlibDecoder, write::ZlibEncoder, Compression};
@@ -67,8 +68,8 @@ fn mk_chunk_vecs(nr_blocks: u64, nr_jobs: u64) -> Vec<Vec<(u64, u64)>> {
     vs
 }
 
-pub fn pack(input_file: &str, output_file: &str) -> Result<(), Box<dyn Error>> {
+pub fn pack(input_file: &str, output_file: &str) -> Result<()> {
-    let nr_blocks = get_nr_blocks(&input_file)?;
+    let nr_blocks = get_nr_blocks(&input_file).context("getting nr blocks")?;
     let nr_jobs = std::cmp::max(1, std::cmp::min(num_cpus::get() as u64, nr_blocks / 128));
     let chunk_vecs = mk_chunk_vecs(nr_blocks, nr_jobs);
 
@@ -85,7 +86,7 @@ pub fn pack(input_file: &str, output_file: &str) -> Result<(), Box<dyn Error>> {
         .truncate(true)
         .open(output_file)?;
 
-    write_header(&output, nr_blocks)?;
+    write_header(&output, nr_blocks).context("unable to write pack file header")?;
 
     let sync_input = Arc::new(Mutex::new(input));
     let sync_output = Arc::new(Mutex::new(output));
@@ -108,7 +109,7 @@ fn crunch<R, W>(
     input: Arc<Mutex<R>>,
     output: Arc<Mutex<W>>,
     ranges: Vec<(u64, u64)>,
-) -> io::Result<()>
+) -> Result<()>
 where
     R: Read + Seek,
     W: Write,
@@ -128,7 +129,7 @@ where
             let kind = metadata_block_type(data);
             if kind != BT::UNKNOWN {
                 z.write_u64::<LittleEndian>(b)?;
-                pack_block(&mut z, kind, &data);
+                pack_block(&mut z, kind, &data)?;
 
                 written += 1;
                 if written == 1024 {
@@ -242,22 +243,18 @@ fn metadata_block_type(buf: &[u8]) -> BT {
     }
 }
 
-fn check<T>(r: &PResult<T>) {
+fn pack_block<W: Write>(w: &mut W, kind: BT, buf: &[u8]) -> Result<()> {
-    match r {
-        Ok(_) => {}
-        Err(PackError::ParseError) => panic!("parse error"),
-        Err(PackError::IOError) => panic!("io error"),
-    }
-}
-
-fn pack_block<W: Write>(w: &mut W, kind: BT, buf: &[u8]) {
     match kind {
-        BT::SUPERBLOCK => check(&pack_superblock(w, buf)),
+        BT::SUPERBLOCK => pack_superblock(w, buf).context("unable to pack superblock")?,
-        BT::NODE => check(&pack_btree_node(w, buf)),
+        BT::NODE => pack_btree_node(w, buf).context("unable to pack btree node")?,
-        BT::INDEX => check(&pack_index(w, buf)),
+        BT::INDEX => pack_index(w, buf).context("unable to pack space map index")?,
-        BT::BITMAP => check(&pack_bitmap(w, buf)),
+        BT::BITMAP => pack_bitmap(w, buf).context("unable to pack space map bitmap")?,
-        BT::UNKNOWN => {panic!("asked to pack an unknown block type")}
+        BT::UNKNOWN => {
+            return Err(anyhow!("asked to pack an unknown block type"))
+        }
     }
+
+    Ok(())
 }
 
 fn write_zero_block<W>(w: &mut W, b: u64) -> io::Result<()>