use std::io::prelude::*; use std::io::SeekFrom; use std::path::Path; use std::fs::File; use integer_encoding::FixedInt; use std::fs::OpenOptions; use errors::*; /// Abstract access to SLEEP content /// /// Back-ends could be in RAM, on disk, remote HTTP, etc. pub trait SleepStorage { /// Returns the 32-bit "magic word", indicating the content type, in native format (aka, not /// necessarily big-endian). fn get_magic(&self) -> u32; /// If the algorithm string is empty, returns None, otherwise the String (owned), decoded from /// UTF-8. Encoded (bytes) representation is at most 24 bytes. fn get_algorithm(&self) -> Option; /// Size (in bytes) of each entry for this SLEEP file. fn get_entry_size(&self) -> u16; /// Returns a single raw entry at the given index (which is not a byte offset). /// TODO: should write into a supplied buffer and return size. fn read(&mut self, index: u64) -> Result>; /// Writes an entry at the given entry index (which is not a byte offset). fn write(&mut self, index: u64, data: &[u8]) -> Result<()>; /// Writes a new entry at the end of the file fn append(&mut self, data: &[u8]) -> Result<()>; /// Returns the count of entries, meaning the highest index entry plus one (not necessarily the /// number of entries which have actually been written). fn len(&self) -> Result; } /// Local File implementation of SleepStorage #[derive(Debug)] pub struct SleepFile { pub file: File, magic: u32, entry_size: u16, // Option isn't necessary here... idiomatic? algorithm_name: Option, } impl SleepFile { // TODO: 'from' pre-existing File // Something here to allow paths as references or actual Path... pub fn open(path: &Path, writable: bool) -> Result { let mut f = OpenOptions::new() .read(true) .write(writable) .create(false) .open(path)?; let mut header = [0; 32]; f.read_exact(&mut header)?; let version: u8 = header[4]; if version != 0 { bail!("Invalid SLEEP header: version must be 0"); } let algo_len: u8 = header[7]; if algo_len > 24 { bail!("Invalid SLEEP header: can't have algo_len > 24"); } let algorithm_name = if algo_len == 0 { None } else { Some(String::from_utf8_lossy(&header[8..(8+(algo_len as usize))]).into_owned()) }; let sf = SleepFile { file: f, magic: u32::from_be(FixedInt::decode_fixed(&header[0..4])), entry_size: u16::from_be(FixedInt::decode_fixed(&header[5..7])), algorithm_name: algorithm_name, }; // call length for consistency checks sf.len()?; Ok(sf) } /// This function will *not* allow overwriting an existing file. pub fn create(path: &Path, magic: u32, entry_size: u16, algo: Option) -> Result { let mut header = [0; 32]; u32::to_be(magic).encode_fixed(&mut header[0..4]); header[4] = 0; // version u16::to_be(entry_size).encode_fixed(&mut header[5..7]); if let Some(name) = algo.clone() { let name = name.as_bytes(); let algo_len = name.len(); if algo_len > 24 { bail!("Algorithm name must be 24 bytes at most"); } header[7] = algo_len as u8; header[8..(8+algo_len)].clone_from_slice(name); } else { header[7] = 0; }; let mut f = OpenOptions::new() .read(true) .write(true) .create_new(true) .open(path)?; f.write_all(&header)?; Ok(SleepFile { file: f, magic: magic, entry_size: entry_size, algorithm_name: algo, }) } } impl SleepStorage for SleepFile { fn get_magic(&self) -> u32 { self.magic } fn get_algorithm(&self) -> Option { self.algorithm_name.clone() } fn get_entry_size(&self) -> u16 { self.entry_size } fn read(&mut self, index: u64) -> Result> { let entry_size = self.entry_size as usize; if index + 1 > self.len()? { bail!("Tried to read beyond end of SLEEP file"); } let mut entry = vec![0; entry_size]; self.file.seek(SeekFrom::Start(32 + (entry_size as u64) * index))?; self.file.read_exact(&mut entry)?; Ok(entry) } fn write(&mut self, index: u64, data: &[u8]) -> Result<()> { // TODO: need to extend file seek beyond end? if data.len() != self.entry_size as usize { bail!("Tried to write mis-sized data"); } self.file.seek(SeekFrom::Start(32 + (self.entry_size as u64) * index))?; self.file.write_all(&data)?; Ok(()) } fn append(&mut self, data: &[u8]) -> Result<()> { let index = self.len()?; self.write(index, data) } fn len(&self) -> Result { let length = self.file.metadata()?.len(); if length < 32 || (length - 32) % (self.entry_size as u64) != 0 { bail!("Bad SLEEP file: missing header or not multiple of entry_size"); } return Ok((length - 32) / (self.entry_size as u64)) } } #[test] fn test_sleep_open() { let sf = SleepFile::open( Path::new("test-data/sleep/empty/empty.sleep"), false).unwrap(); assert_eq!(sf.len().unwrap(), 0); assert_eq!(sf.get_magic(), 0x050257FF); assert_eq!(sf.get_algorithm(), None); assert_eq!(sf.get_entry_size(), 1); let sf = SleepFile::open( Path::new("test-data/dat/simple/.dat/metadata.tree"), false).unwrap(); // Calculated from 'dat log' assert_eq!(sf.len().unwrap(), 5); assert_eq!(sf.get_magic(), 0x05025702); assert_eq!(sf.get_algorithm(), Some("BLAKE2b".to_string())); assert_eq!(sf.get_entry_size(), 40); } #[test] fn test_sleep_create() { use tempdir::TempDir; let tmp_dir = TempDir::new("geniza-test").unwrap(); SleepFile::create( &tmp_dir.path().join("empty2.sleep"), 0x050257FF, 1, None).unwrap(); // TODO: binary diff against 'test-data/sleep/empty/empty.sleep' SleepFile::create( &tmp_dir.path().join("simple_metadata.sleep"), 0x05025702, 40, Some("BLAKE2b".into())).unwrap(); }