[thin_shrink] Get test framework built

This verifies data has been moved to the correct place.

src/bin/thin_metadata_pack.rs

@@ -2,6 +2,7 @@ extern crate clap;
 extern crate thinp;
 
 use clap::{App, Arg};
+use std::path::Path;
 use std::process::exit;
 use thinp::file_utils;
 
@@ -23,14 +24,14 @@ fn main() {
             .takes_value(true));
 
     let matches = parser.get_matches();
-    let input_file = matches.value_of("INPUT").unwrap();
-    let output_file = matches.value_of("OUTPUT").unwrap();
+    let input_file = Path::new(matches.value_of("INPUT").unwrap());
+    let output_file = Path::new(matches.value_of("OUTPUT").unwrap());
 
-    if !file_utils::file_exists(input_file) {
-        eprintln!("Couldn't find input file '{}'.", &input_file);
+    if !file_utils::file_exists(&input_file) {
+        eprintln!("Couldn't find input file '{}'.", &input_file.display());
         exit(1);
     }
-    
+
     if let Err(reason) = thinp::pack::toplevel::pack(&input_file, &output_file) {
         println!("Application error: {}\n", reason);
         exit(1);

src/bin/thin_metadata_unpack.rs

@@ -2,6 +2,7 @@ extern crate clap;
 extern crate thinp;
 
 use clap::{App, Arg};
+use std::path::Path;
 use std::process;
 use thinp::file_utils;
 
@@ -9,30 +10,34 @@ use std::process::exit;
 
 fn main() {
     let parser = App::new("thin_metadata_unpack")
-	.version(thinp::version::TOOLS_VERSION)
+        .version(thinp::version::TOOLS_VERSION)
         .about("Unpack a compressed file of thin metadata.")
-        .arg(Arg::with_name("INPUT")
-            .help("Specify thinp metadata binary device/file")
-            .required(true)
-            .short("i")
-            .value_name("DEV")
-            .takes_value(true))
-        .arg(Arg::with_name("OUTPUT")
-            .help("Specify packed output file")
-            .required(true)
-            .short("o")
-            .value_name("FILE")
-            .takes_value(true));
+        .arg(
+            Arg::with_name("INPUT")
+                .help("Specify thinp metadata binary device/file")
+                .required(true)
+                .short("i")
+                .value_name("DEV")
+                .takes_value(true),
+        )
+        .arg(
+            Arg::with_name("OUTPUT")
+                .help("Specify packed output file")
+                .required(true)
+                .short("o")
+                .value_name("FILE")
+                .takes_value(true),
+        );
 
     let matches = parser.get_matches();
-    let input_file = matches.value_of("INPUT").unwrap();
-    let output_file = matches.value_of("OUTPUT").unwrap();
+    let input_file = Path::new(matches.value_of("INPUT").unwrap());
+    let output_file = Path::new(matches.value_of("OUTPUT").unwrap());
 
     if !file_utils::file_exists(input_file) {
-        eprintln!("Couldn't find input file '{}'.", &input_file);
+        eprintln!("Couldn't find input file '{}'.", &input_file.display());
         exit(1);
     }
-    
+
     if let Err(reason) = thinp::pack::toplevel::unpack(&input_file, &output_file) {
         println!("Application error: {}", reason);
         process::exit(1);

src/bin/thin_shrink.rs

@@ -2,6 +2,7 @@ extern crate clap;
 extern crate thinp;
 
 use clap::{App, Arg};
+use std::path::Path;
 use std::process::exit;
 use thinp::file_utils;
 
@@ -53,18 +54,20 @@ fn main() {
     let matches = parser.get_matches();
 
     // FIXME: check these look like xml
-    let input_file = matches.value_of("INPUT").unwrap();
-    let output_file = matches.value_of("OUTPUT").unwrap();
+    let input_file = Path::new(matches.value_of("INPUT").unwrap());
+    let output_file = Path::new(matches.value_of("OUTPUT").unwrap());
     let size = matches.value_of("SIZE").unwrap().parse::<u64>().unwrap();
-    let data_file = matches.value_of("DATA").unwrap();
+    let data_file = Path::new(matches.value_of("DATA").unwrap());
     let do_copy = !matches.is_present("NOCOPY");
 
     if !file_utils::file_exists(input_file) {
-        eprintln!("Couldn't find input file '{}'.", &input_file);
+        eprintln!("Couldn't find input file '{}'.", input_file.display());
         exit(1);
     }
 
-    if let Err(reason) = thinp::shrink::toplevel::shrink(&input_file, &output_file, &data_file, size, do_copy) {
+    if let Err(reason) =
+        thinp::shrink::toplevel::shrink(&input_file, &output_file, &data_file, size, do_copy)
+    {
         println!("Application error: {}\n", reason);
         exit(1);
     }

src/file_utils.rs

@@ -1,9 +1,10 @@
 use nix::sys::stat;
 use nix::sys::stat::{FileStat, SFlag};
-use std::fs::File;
+use std::fs::{File, OpenOptions};
 use std::io;
 use std::io::{Seek, Write};
 use std::os::unix::io::AsRawFd;
+use std::path::Path;
 use tempfile::tempfile;
 
 //---------------------------------------
@@ -17,7 +18,7 @@ pub fn is_file_or_blk(info: FileStat) -> bool {
         || check_bits(info.st_mode, &stat::SFlag::S_IFREG)
 }
 
-pub fn file_exists(path: &str) -> bool {
+pub fn file_exists(path: &Path) -> bool {
     match stat::stat(path) {
         Ok(info) => is_file_or_blk(info),
         _ => {
@@ -39,7 +40,7 @@ pub fn fail<T>(msg: &str) -> io::Result<T> {
     Err(e)
 }
 
-fn get_device_size(path: &str) -> io::Result<u64> {
+fn get_device_size(path: &Path) -> io::Result<u64> {
     let file = File::open(path)?;
     let fd = file.as_raw_fd();
     let mut cap = 0u64;
@@ -51,7 +52,7 @@ fn get_device_size(path: &str) -> io::Result<u64> {
     }
 }
 
-pub fn file_size(path: &str) -> io::Result<u64> {
+pub fn file_size(path: &Path) -> io::Result<u64> {
     match stat::stat(path) {
         Ok(info) => {
             if check_bits(info.st_mode, &SFlag::S_IFREG) {
@@ -68,16 +69,31 @@ pub fn file_size(path: &str) -> io::Result<u64> {
 
 //---------------------------------------
 
-pub fn temp_file_sized(nr_bytes: u64) -> io::Result<std::fs::File> {
-    let mut file = tempfile()?;
-
+fn set_size<W: Write + Seek>(w: &mut W, nr_bytes: u64) -> io::Result<()> {
     let zeroes: Vec<u8> = vec![0; 1];
 
     if nr_bytes > 0 {
-        file.seek(io::SeekFrom::Start(nr_bytes - 1))?;
-        file.write_all(&zeroes)?;
+        w.seek(io::SeekFrom::Start(nr_bytes - 1))?;
+        w.write_all(&zeroes)?;
     }
 
+    Ok(())
+}
+
+pub fn temp_file_sized(nr_bytes: u64) -> io::Result<std::fs::File> {
+    let mut file = tempfile()?;
+    set_size(&mut file, nr_bytes)?;
+    Ok(file)
+}
+
+pub fn create_sized_file(path: &Path, nr_bytes: u64) -> io::Result<std::fs::File> {
+    let mut file = OpenOptions::new()
+        .read(false)
+        .write(true)
+        .create(true)
+        .truncate(true)
+        .open(path)?;
+    set_size(&mut file, nr_bytes)?;
     Ok(file)
 }
 

src/pack/toplevel.rs

@@ -6,6 +6,7 @@ use std::os::unix::fs::OpenOptionsExt;
 use std::{
     error::Error,
     fs::OpenOptions,
+    path::Path,
     io,
     io::prelude::*,
     io::Cursor,
@@ -67,7 +68,7 @@ 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: &Path, output_file: &Path) -> Result<(), Box<dyn Error>> {
     let nr_blocks = get_nr_blocks(&input_file)?;
     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);
@@ -192,7 +193,7 @@ where
     r.read_u64::<LittleEndian>()
 }
 
-fn get_nr_blocks(path: &str) -> io::Result<u64> {
+fn get_nr_blocks(path: &Path) -> io::Result<u64> {
     let len = file_utils::file_size(path)?;
     Ok(len / (BLOCK_SIZE as u64))
 }
@@ -306,7 +307,7 @@ where
     Ok(())
 }
 
-pub fn unpack(input_file: &str, output_file: &str) -> Result<(), Box<dyn Error>> {
+pub fn unpack(input_file: &Path, output_file: &Path) -> Result<(), Box<dyn Error>> {
     let mut input = OpenOptions::new()
         .read(true)
         .write(false)

src/shrink/copier.rs

@@ -1,5 +1,6 @@
 use anyhow::Result;
 use std::fs::OpenOptions;
+use std::path::Path;
 use std::io::{Seek, SeekFrom, Write, Read};
 //use std::os::unix::fs::OpenOptionsExt;
 
@@ -43,7 +44,7 @@ where
     Ok(())
 }
 
-pub fn copy(path: &str, regions: &[Region]) -> Result<()> {
+pub fn copy(path: &Path, regions: &[Region]) -> Result<()> {
     let mut input = OpenOptions::new()
         .read(true)
         .write(true)

src/shrink/toplevel.rs

@@ -3,6 +3,7 @@ use fixedbitset::FixedBitSet;
 use std::fs::OpenOptions;
 use std::io::Write;
 use std::os::unix::fs::OpenOptionsExt;
+use std::path::Path;
 
 use crate::shrink::copier::{self, Region};
 use crate::thin::xml::{self, Visit};
@@ -426,7 +427,7 @@ fn build_copy_regions(remaps: &[(BlockRange, BlockRange)], block_size: u64) -> V
     rs
 }
 
-fn process_xml<MV: xml::MetadataVisitor>(input_path: &str, pass: &mut MV) -> Result<()> {
+fn process_xml<MV: xml::MetadataVisitor>(input_path: &Path, pass: &mut MV) -> Result<()> {
     let input = OpenOptions::new()
         .read(true)
         .write(false)
@@ -437,7 +438,13 @@ fn process_xml<MV: xml::MetadataVisitor>(input_path: &str, pass: &mut MV) -> Res
     Ok(())
 }
 
-pub fn shrink(input_path: &str, output_path: &str, data_path: &str, nr_blocks: u64, do_copy: bool) -> Result<()> {
+pub fn shrink(
+    input_path: &Path,
+    output_path: &Path,
+    data_path: &Path,
+    nr_blocks: u64,
+    do_copy: bool,
+) -> Result<()> {
     let mut pass1 = Pass1::new(nr_blocks);
     eprint!("Reading xml...");
     process_xml(input_path, &mut pass1)?;

tests/thin_shrink.rs

@@ -3,6 +3,8 @@ use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
 use rand::Rng;
 use std::fs::OpenOptions;
 use std::io::{Cursor, Read, Seek, SeekFrom, Write};
+use std::path::{Path, PathBuf};
+use tempfile::tempdir;
 
 use thinp::file_utils;
 use thinp::thin::xml::{self, Visit};
@@ -22,6 +24,7 @@ struct ThinReadRef {
 
 struct ThinWriteRef<'a, W: Write + Seek> {
     file: &'a mut W,
+    block_byte: u64,
     pub data: Vec<u8>,
 }
 
@@ -38,6 +41,7 @@ impl ThinBlock {
     fn zero_ref<'a, W: Write + Seek>(&self, w: &'a mut W) -> ThinWriteRef<'a, W> {
         ThinWriteRef {
             file: w,
+            block_byte: self.data_block * (self.block_size as u64),
             data: vec![0; self.block_size],
         }
     }
@@ -52,6 +56,7 @@ impl ThinBlock {
 
         let wr = ThinWriteRef {
             file: w,
+            block_byte: self.data_block * (self.block_size as u64),
             data: vec![0; self.block_size],
         };
 
@@ -61,6 +66,10 @@ impl ThinBlock {
 
 impl<'a, W: Write + Seek> Drop for ThinWriteRef<'a, W> {
     fn drop(&mut self) {
+        // FIXME: We shouldn't panic in a drop function, so any IO
+        // errors will have to make their way back to the user
+        // another way (eg, via a flush() method).
+        self.file.seek(SeekFrom::Start(self.block_byte)).unwrap();
         self.file.write_all(&self.data[0..]).unwrap();
     }
 }
@@ -232,28 +241,105 @@ impl<'a, R: Read + Seek> ThinVisitor for Verifier<'a, R> {
 
 //------------------------------------
 
-fn create_data_file(xml_path: &str) -> Result<std::fs::File> {
+fn mk_path(dir: &Path, file: &str) -> PathBuf {
+    let mut p = PathBuf::new();
+    p.push(dir);
+    p.push(PathBuf::from(file));
+    p
+}
+
+fn generate_xml<G>(path: &Path, g: &mut G) -> Result<()>
+where
+    G: XmlGenerator,
+{
+    let xml_out = OpenOptions::new()
+        .read(false)
+        .write(true)
+        .create(true)
+        .truncate(true)
+        .open(path)?;
+    let mut w = xml::XmlWriter::new(xml_out);
+
+    g.generate(&mut w)
+}
+
+fn create_data_file(data_path: &Path, xml_path: &Path) -> Result<()> {
     let input = OpenOptions::new().read(true).write(false).open(xml_path)?;
 
     let sb = xml::read_superblock(input)?;
     let nr_blocks = sb.nr_data_blocks as u64;
     let block_size = sb.data_block_size as u64 * 512;
 
-    let file = file_utils::temp_file_sized(nr_blocks * block_size)?;
-    Ok(file)
+    let _file = file_utils::create_sized_file(data_path, nr_blocks * block_size)?;
+    Ok(())
 }
 
-fn main(xml_path: &str) -> Result<()> {
-    let mut data_file = create_data_file(xml_path)?;
-    let mut xml_in = OpenOptions::new().read(true).write(false).open(xml_path)?;
+fn stamp(xml_path: &Path, data_path: &Path, seed: u64) -> Result<()> {
+    let mut data = OpenOptions::new()
+        .read(false)
+        .write(true)
+        .open(&data_path)?;
+    let xml = OpenOptions::new().read(true).write(false).open(&xml_path)?;
+
+    let mut stamper = Stamper::new(&mut data, seed);
+    thin_visit(xml, &mut stamper)
+}
+
+fn verify(xml_path: &Path, data_path: &Path, seed: u64) -> Result<()> {
+    let mut data = OpenOptions::new()
+        .read(true)
+        .write(false)
+        .open(&data_path)?;
+    let xml = OpenOptions::new().read(true).write(false).open(&xml_path)?;
+
+    let mut verifier = Verifier::new(&mut data, seed);
+    thin_visit(xml, &mut verifier)
+}
+
+//------------------------------------
+
+trait XmlGenerator {
+    fn generate(&mut self, v: &mut dyn xml::MetadataVisitor) -> Result<()>;
+}
+
+struct EmptyPoolG {}
+
+impl XmlGenerator for EmptyPoolG {
+    fn generate(&mut self, v: &mut dyn xml::MetadataVisitor) -> Result<()> {
+        v.superblock_b(&xml::Superblock {
+            uuid: "".to_string(),
+            time: 0,
+            transaction: 0,
+            flags: None,
+            version: None,
+            data_block_size: 64,
+            nr_data_blocks: 1024,
+            metadata_snap: None,
+        })?;
+        v.superblock_e()?;
+        Ok(())
+    }
+}
+
+#[test]
+fn shrink_empty_pool() -> Result<()> {
+    let dir = tempdir()?;
+    let xml_before = mk_path(dir.path(), "before.xml");
+    let xml_after = mk_path(dir.path(), "after.xml");
+    let data_path = mk_path(dir.path(), "bin");
+
+    let mut gen = EmptyPoolG {};
+    generate_xml(&xml_before, &mut gen)?;
+    create_data_file(&data_path, &xml_before)?;
 
     let mut rng = rand::thread_rng();
     let seed = rng.gen::<u64>();
 
-    let mut stamper = Stamper::new(&mut data_file, seed);
-    thin_visit(&mut xml_in, &mut stamper)?;
+    stamp(&xml_before, &data_path, seed)?;
 
-    let mut verifier = Verifier::new(&mut data_file, seed);
-    thin_visit(&mut xml_in, &mut verifier)?;
+    let new_nr_blocks = 10;
+    thinp::shrink::toplevel::shrink(&xml_before, &xml_after, &data_path, new_nr_blocks, true)?;
+
+    verify(&xml_after, &data_path, seed)?;
     Ok(())
 }