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-rw-r--r--src/sleep_file.rs203
1 files changed, 203 insertions, 0 deletions
diff --git a/src/sleep_file.rs b/src/sleep_file.rs
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+++ b/src/sleep_file.rs
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+
+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<String>;
+
+ /// 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<Vec<u8>>;
+
+ /// 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<u64>;
+}
+
+/// 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<String>,
+}
+
+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<SleepFile> {
+
+ 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<String>) -> Result<SleepFile> {
+
+ 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<String> { self.algorithm_name.clone() }
+ fn get_entry_size(&self) -> u16 { self.entry_size }
+
+ fn read(&mut self, index: u64) -> Result<Vec<u8>> {
+ 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<u64> {
+ 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();
+}