Add default traits and open function to CompressionEngine

src/compression.rs

@@ -1,9 +1,13 @@
 use anyhow::{Result};
 use strum::IntoEnumIterator;
 use std::path::PathBuf;
-use std::io::Write;
+use std::io::{Read,Write};
+use std::io;
+
+use log::*;
 
 use lazy_static::lazy_static;
+
 extern crate enum_map;
 use enum_map::enum_map;
 use enum_map::{EnumMap,Enum};
@@ -31,9 +35,38 @@ pub enum CompressionType {
 
 
 pub trait CompressionEngine {
-    fn is_supported(&self) -> bool;
-    fn cat(&self, file_path: PathBuf) -> Result<()>;
+    fn open(&self, file_path: PathBuf) -> Result<Box<dyn Read>>;
     fn create(&self, file_path: PathBuf) -> Result<Box<dyn Write>>;
+
+    fn is_supported(&self) -> bool {
+        true
+    }
+
+    fn cat(&self, file_path: PathBuf) -> Result<()> {
+        let mut reader = self.open(file_path)?;
+        let mut stdout = io::stdout().lock();
+        io::copy(&mut reader, &mut stdout)?;
+        stdout.flush()?;
+        Ok(())
+    }
+
+    fn size(&self, file_path: PathBuf) -> Result<usize> {
+        let mut reader = self.open(file_path)?;
+        let mut buffer = [0; libc::BUFSIZ as usize];
+        let mut size: usize = 0;
+
+        loop {
+            let n = reader.read(&mut buffer[..libc::BUFSIZ as usize])?;
+            if n == 0 {
+                debug!("COMPREESSION: EOF");
+                break;
+            }
+
+            size = size + n;
+        }
+
+        Ok(size)
+    }
 }
 
 

src/compression/gzip.rs

@@ -1,7 +1,7 @@
 use anyhow::Result;
 use std::fs::File;
 use std::io;
-use std::io::Write;
+use std::io::{Read,Write};
 use std::path::PathBuf;
 use log::*;
 
@@ -25,17 +25,11 @@ impl CompressionEngine for CompressionEngineGZip {
         true
     }
 
-    fn cat(&self, file_path: PathBuf) -> Result<()> {
-        debug!("COMPRESSION: Outputting {:?} to STDOUT using {:?}", file_path, *self);
+    fn open(&self, file_path: PathBuf) -> Result<Box<dyn Read>> {
+        debug!("COMPRESSION: Opening {:?} using {:?}", file_path, *self);
 
-        let mut stdout = io::stdout().lock();
         let file = File::open(file_path)?;
-        let mut gzip_read = GzDecoder::new(file);
-
-        io::copy(&mut gzip_read, &mut stdout)?;
-        stdout.flush()?;
-
-        Ok(())
+        Ok(Box::new(GzDecoder::new(file)))
     }
 
     fn create(&self, file_path: PathBuf) -> Result<Box<dyn Write>> {

src/compression/lz4.rs

@@ -1,7 +1,6 @@
 use anyhow::Result;
 use std::fs::File;
-use std::io;
-use std::io::Write;
+use std::io::{Read,Write};
 use std::path::PathBuf;
 use log::*;
 
@@ -24,17 +23,11 @@ impl CompressionEngine for CompressionEngineLZ4 {
         true
     }
 
-    fn cat(&self, file_path: PathBuf) -> Result<()> {
-        debug!("COMPRESSION: Outputting {:?} to STDOUT using {:?}", file_path, *self);
+    fn open(&self, file_path: PathBuf) -> Result<Box<dyn Read>> {
+        debug!("COMPRESSION: Opening {:?} using {:?}", file_path, *self);
 
-        let mut stdout = io::stdout().lock();
         let file = File::open(file_path)?;
-        let mut lz4_read = FrameDecoder::new(file);
-
-        io::copy(&mut lz4_read, &mut stdout)?;
-        stdout.flush()?;
-
-        Ok(())
+        Ok(Box::new(FrameDecoder::new(file)))
     }
 
     fn create(&self, file_path: PathBuf) -> Result<Box<dyn Write>> {

src/compression/none.rs

@@ -1,7 +1,6 @@
 use anyhow::Result;
 use std::fs::File;
-use std::io;
-use std::io::Write;
+use std::io::{Read,Write};
 use std::path::PathBuf;
 use log::*;
 
@@ -17,19 +16,14 @@ impl CompressionEngineNone {
 }
 
 impl CompressionEngine for CompressionEngineNone {
-    fn is_supported(&self) -> bool {
-        true
+    fn size(&self, file_path: PathBuf) -> Result<usize> {
+        let item_file_metadata = file_path.metadata()?;
+        Ok(item_file_metadata.len() as usize)
     }
 
-    fn cat(&self, file_path: PathBuf) -> Result<()> {
-        debug!("COMPRESSION: Outputting {:?} to STDOUT using {:?}", file_path, *self);
-        let mut stdout = io::stdout().lock();
-        let mut file = File::open(file_path)?;
-
-        io::copy(&mut file, &mut stdout)?;
-        stdout.flush()?;
-
-        Ok(())
+    fn open(&self, file_path: PathBuf) -> Result<Box<dyn Read>> {
+        debug!("COMPRESSION: Opening {:?} using {:?}", file_path, *self);
+        Ok(Box::new(File::open(file_path)?))
     }
 
     fn create(&self, file_path: PathBuf) -> Result<Box<dyn Write>> {

src/compression/program.rs

@@ -1,6 +1,6 @@
 use anyhow::{Context, Result, anyhow};
 use std::fs::File;
-use std::io::Write;
+use std::io::{Read,Write};
 use std::process::{Command,Stdio};
 use std::path::PathBuf;
 use std::env;
@@ -39,29 +39,23 @@ impl CompressionEngine for CompressionEngineProgram {
         self.supported
     }
 
-    fn cat(&self, file_path: PathBuf) -> Result<()> {
-        debug!("COMPRESSION: Outputting {:?} to STDOUT using {:?}", file_path, *self);
+    fn open(&self, file_path: PathBuf) -> Result<Box<dyn Read>> {
+        debug!("COMPRESSION: Opening {:?} using {:?}", file_path, *self);
+
         let program = self.program.clone();
         let args = self.decompress.clone();
 
-        debug!("COMPRESSION: Executing command: {:?} {:?} writing to {:?}", program, args, file_path);
+        debug!("COMPRESSION: Executing command: {:?} {:?} reading from {:?}", program, args, file_path);
 
         let file = File::open(file_path).context("Unable to open file for reading")?;
 
-        let mut process = Command::new(program.clone())
+        let process = Command::new(program.clone())
             .args(args.clone())
             .stdin(file)
+            .stdout(Stdio::piped())
             .spawn()
             .context(anyhow!("Unable to spawn child process: {:?} {:?}", program, args))?;
-
-        let result = process.wait()
-            .context(anyhow!("Unable to wait for child process: {:?} {:?}", program, args))?;
-
-        if result.success() {
-            Ok(())
-        } else {
-            Err(anyhow!("Decompression program returned {}", result))
-        }
+        Ok(Box::new(process.stdout.unwrap()))
     }
 
     fn create(&self, file_path: PathBuf) -> Result<Box<dyn Write>> {