start db

src/database.rs

@@ -0,0 +1,94 @@
+//! Database manipulation stuffs
+use super::*;
+use std::{
+    path::{
+	PathBuf,
+    },
+    error,
+    fmt,
+    io,
+    marker::Unpin,
+};
+/// An error in database operations
+#[derive(Debug)]
+#[non_exhaustive]
+pub enum Error {
+    ExpectedLine(Option<String>),
+    IO(io::Error),
+    Unknown,
+}
+impl error::Error for Error
+{
+    fn source(&self) -> Option<&(dyn error::Error + 'static)> {
+	match &self {
+	    Self::IO(io) => Some(io),
+	    _ => None,
+	}
+    }
+}
+impl fmt::Display for Error
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
+    {
+	match self {
+	    Self::IO(_)=> write!(f, "i/o"),
+	    Self::ExpectedLine(None) => write!(f, "expected a line that was not present in the file"),
+	    Self::ExpectedLine(Some(msg)) => write!(f, "{}", msg),
+	    _ => write!(f, "unknown"),
+	}
+    }
+}
+
+
+
+/// Contains Videl information for a database directory
+#[derive(Debug, Clone, PartialEq, Ord, Eq, PartialOrd, Hash)]
+pub struct Database
+{
+    pub path: PathBuf,
+}
+
+impl Database
+{
+    /// Save this database to a stream
+    pub async fn save<T: AsyncWrite + Unpin + ?Sized>(&self, stream: &mut T) -> Result<usize, Error>
+    {
+	let bytes = resolve::path_bytes(&self.path);
+	stream.write_all(&bytes[..]).await?;
+	stream.write_u8(b'\n').await?;
+	Ok(bytes.len() + 1)
+    }
+}
+
+
+/// Load database info from this file
+pub async fn load<T: AsyncBufRead + Unpin + ?Sized>(stream: &mut T) -> Result<Database, Error>
+{
+    let mut buffer = String::new();
+    macro_rules! line {
+	($message:literal $($tt:tt)*) => {
+	    {
+		buffer.clear();
+		let read = stream.read_line(&mut buffer).await?;
+		if read == 0  {
+		    return Err(Error::ExpectedLine(Some(format!($message $($tt)*))));
+		}
+		&buffer[..]
+	    }
+	}
+    }
+
+    let location_encoded = line!("expected the location line");
+
+    Ok(Database{
+	path: PathBuf::from(location_encoded),
+    })
+}
+
+impl From<io::Error> for Error
+{
+    #[inline] fn from(from: io::Error) -> Self
+    {
+	Self::IO(from)
+    }
+}

src/main.rs

@@ -4,7 +4,11 @@
 
 use cfg_if::cfg_if;
 use lazy_static::lazy_static;
-use futures::prelude::*;
+//use futures::prelude::*;
+use tokio::prelude::*;
+use futures::{
+    Future,
+};
 
 #[allow(unused_imports)]
 use color_eyre::{
@@ -21,12 +25,15 @@ use std::{
 
 mod ext;
 use ext::*;
-
 mod util;
+mod dedup;
+
+mod resolve;
+mod database;
+
 mod args;
 mod config;
-mod resolve;
-mod dedup;
+
 
 cfg_if!{
     if #[cfg(nightly)] {
@@ -50,7 +57,11 @@ async fn process(config: Arc<config::Config>, file: String)
     println!(" -> {:?}", file);
     let dbdir = resolve::mangle_path(&config, &file);
     println!("Database path for this file {:?}", dbdir);
-    println!("Demangle: {:?}", resolve::demangle_path(&dbdir).await);
+    println!("Demangle: {:?}", resolve::demangle_path(&dbdir).await
+	     .wrap_err(eyre!("Failed to demangle path"))
+	     .with_section(|| dbdir.to_string_lossy().into_owned().header("Path was"))
+	     .with_section(|| config.base_dir.clone().to_string_lossy().into_owned().header("The videl database root directory is"))
+	     .with_suggestion(|| "Are you sure this database location is correct"));
 }
 
 async fn begin() -> eyre::Result<i32>

src/resolve.rs

@@ -8,8 +8,14 @@ use std::{
     collections::HashMap,
     fmt,
     error,
+    borrow::Cow,
 };
 use std::os::unix::ffi::{OsStrExt, OsStringExt};
+use tokio::{
+    fs::{
+	OpenOptions,
+    },
+};
 
 #[cfg(not(feature="fast-pathnames"))] 
 fn compute_hash_string(from: impl AsRef<[u8]>) -> String
@@ -55,14 +61,44 @@ pub fn mangle_path(config: &config::Config, path: impl AsRef<Path>) -> PathBuf
 }
 
 #[derive(Debug)]
-pub struct ResolutionError;
+#[non_exhaustive]
+pub enum ResolutionError
+{
+    Name,
+    Utf8,
+    #[cfg(feature="fast-pathnames")] 
+    Base64Decode(base64::Error),
+    IO(io::Error),
+    Open(io::Error),
+    Database(database::Error),
+    Unknown,
+}
 
-impl error::Error for ResolutionError{}
+impl error::Error for ResolutionError
+{
+    fn source(&self) -> Option<&(dyn error::Error + 'static)> {
+	Some(match &self {
+	    #[cfg(feature="fast-pathnames")] Self::Base64Decode(er) => er,
+	    Self::IO(er)=>er,
+	    Self::Open(er)=>er,
+	    Self::Database(er)=>er,
+	    _ => return None,
+	})
+    }
+}
 impl fmt::Display for ResolutionError
 {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
     {
-	write!(f, "database path was in an invalid format")
+	match self {
+	    Self::Name => write!(f, "invalid pathname"),
+	    Self::Utf8 => write!(f, "pathname contained invalid UTF-8"),
+	    #[cfg(feature="fast-pathnames")] Self::Base64Decode(_) => write!(f, "failed to decode base64 pathname"),
+	    Self::IO(_) => write!(f, "i/o error"),
+	    Self::Open(_) => write!(f, "failed to open file"),
+	    Self::Database(_) => write!(f, "failed to parse database"),
+	    _ => write!(f, "unknown error")
+	}
     }
 }
 
@@ -71,14 +107,26 @@ pub async fn demangle_path(path: impl AsRef<Path>) -> Result<PathBuf, Resolution
 {
     cfg_if! {
 	if #[cfg(feature="fast-pathnames")] {
-	    let part = path.as_ref().file_name().ok_or(ResolutionError)?; //get the base64 encoded part
-	    let part = replace_base64_from(part.to_str().ok_or(ResolutionError)?); //replace characters back
-	    let bytes = base64::decode(part).map_err(|_| ResolutionError)?;
+	    let part = path.as_ref().file_name().ok_or(ResolutionError::Name)?; //get the base64 encoded part
+	    let part = replace_base64_from(part.to_str().ok_or(ResolutionError::Utf8)?); //replace characters back
+	    let bytes = base64::decode(part).map_err(ResolutionError::Base64Decode)?;
 	    
 	    Ok(std::ffi::OsString::from_vec(bytes).into())
 	} else {
-	    //TODO: Look up in `path/metadata` file
-	    todo!()
+	    let metafile = path.as_ref().join("metadata");
+	    let file = OpenOptions::new()
+		.read(true)
+		.open(metafile).await.map_err(ResolutionError::Open)?;
+	    let mut file = tokio::io::BufReader::new(file);
+	    let db = database::load(&mut file).await.map_err(ResolutionError::Database)?;
+	    Ok(db.path)
 	}
     }
 }
+
+/// Get bytes from a path
+pub fn path_bytes<'a, P: AsRef<Path> + ?Sized>(path: &'a P) -> Cow<'a, [u8]>
+{
+    //for now, just use unix ext'ss things
+    Cow::Borrowed(path.as_ref().as_os_str().as_bytes())
+}