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//! Functions for reading from cache. use std::path::Path; use std::pin::Pin; use std::task::{Context as TaskContext, Poll}; use futures::prelude::*; use ssri::{Algorithm, Integrity}; use crate::content::read; use crate::errors::{Error, Result}; use crate::index::{self, Metadata}; // --------- // Async API // --------- /// File handle for reading data asynchronously. /// /// Make sure to call `.check()` when done reading to verify that the /// extracted data passes integrity verification. pub struct Reader { reader: read::AsyncReader, } impl AsyncRead for Reader { fn poll_read( mut self: Pin<&mut Self>, cx: &mut TaskContext<'_>, buf: &mut [u8], ) -> Poll<std::io::Result<usize>> { Pin::new(&mut self.reader).poll_read(cx, buf) } } impl Reader { /// Checks that data read from disk passes integrity checks. Returns the /// algorithm that was used verified the data. Should be called only after /// all data has been read from disk. /// /// This check is very cheap, since most of the verification is done on /// the fly. This simply finalizes verification, and is always /// synchronous. /// /// ## Example /// ```no_run /// use async_std::prelude::*; /// use async_attributes; /// /// #[async_attributes::main] /// async fn main() -> cacache::Result<()> { /// let mut fd = cacache::Reader::open("./my-cache", "my-key").await?; /// let mut str = String::new(); /// fd.read_to_string(&mut str).await.expect("Failed to read to string"); /// // Remember to check that the data you got was correct! /// fd.check()?; /// Ok(()) /// } /// ``` pub fn check(self) -> Result<Algorithm> { self.reader.check() } /// Opens a new file handle into the cache, looking it up in the index using /// `key`. /// /// ## Example /// ```no_run /// use async_std::prelude::*; /// use async_attributes; /// /// #[async_attributes::main] /// async fn main() -> cacache::Result<()> { /// let mut fd = cacache::Reader::open("./my-cache", "my-key").await?; /// let mut str = String::new(); /// fd.read_to_string(&mut str).await.expect("Failed to read to string"); /// // Remember to check that the data you got was correct! /// fd.check()?; /// Ok(()) /// } /// ``` pub async fn open<P, K>(cache: P, key: K) -> Result<Reader> where P: AsRef<Path>, K: AsRef<str>, { if let Some(entry) = index::find_async(cache.as_ref(), key.as_ref()).await? { Reader::open_hash(cache, entry.integrity).await } else { Err(Error::EntryNotFound( cache.as_ref().to_path_buf(), key.as_ref().into(), ))? } } /// Opens a new file handle into the cache, based on its integrity address. /// /// ## Example /// ```no_run /// use async_std::prelude::*; /// use async_attributes; /// /// #[async_attributes::main] /// async fn main() -> cacache::Result<()> { /// let sri = cacache::write("./my-cache", "key", b"hello world").await?; /// let mut fd = cacache::Reader::open_hash("./my-cache", sri).await?; /// let mut str = String::new(); /// fd.read_to_string(&mut str).await.expect("Failed to read to string"); /// // Remember to check that the data you got was correct! /// fd.check()?; /// Ok(()) /// } /// ``` pub async fn open_hash<P>(cache: P, sri: Integrity) -> Result<Reader> where P: AsRef<Path>, { Ok(Reader { reader: read::open_async(cache.as_ref(), sri).await?, }) } } /// Reads the entire contents of a cache file into a bytes vector, looking the /// data up by key. /// /// ## Example /// ```no_run /// use async_std::prelude::*; /// use async_attributes; /// /// #[async_attributes::main] /// async fn main() -> cacache::Result<()> { /// let data: Vec<u8> = cacache::read("./my-cache", "my-key").await?; /// Ok(()) /// } /// ``` pub async fn read<P, K>(cache: P, key: K) -> Result<Vec<u8>> where P: AsRef<Path>, K: AsRef<str>, { if let Some(entry) = index::find_async(cache.as_ref(), key.as_ref()).await? { read_hash(cache, &entry.integrity).await } else { Err(Error::EntryNotFound( cache.as_ref().to_path_buf(), key.as_ref().into(), ))? } } /// Reads the entire contents of a cache file into a bytes vector, looking the /// data up by its content address. /// /// ## Example /// ```no_run /// use async_std::prelude::*; /// use async_attributes; /// /// #[async_attributes::main] /// async fn main() -> cacache::Result<()> { /// let sri = cacache::write("./my-cache", "my-key", b"hello").await?; /// let data: Vec<u8> = cacache::read_hash("./my-cache", &sri).await?; /// Ok(()) /// } /// ``` pub async fn read_hash<P>(cache: P, sri: &Integrity) -> Result<Vec<u8>> where P: AsRef<Path>, { Ok(read::read_async(cache.as_ref(), sri).await?) } /// Copies cache data to a specified location. Returns the number of bytes /// copied. /// /// ## Example /// ```no_run /// use async_std::prelude::*; /// use async_attributes; /// /// #[async_attributes::main] /// async fn main() -> cacache::Result<()> { /// cacache::copy("./my-cache", "my-key", "./data.txt").await?; /// Ok(()) /// } /// ``` pub async fn copy<P, K, Q>(cache: P, key: K, to: Q) -> Result<u64> where P: AsRef<Path>, K: AsRef<str>, Q: AsRef<Path>, { if let Some(entry) = index::find_async(cache.as_ref(), key.as_ref()).await? { copy_hash(cache, &entry.integrity, to).await } else { Err(Error::EntryNotFound( cache.as_ref().to_path_buf(), key.as_ref().into(), ))? } } /// Copies a cache data by hash to a specified location. Returns the number of /// bytes copied. /// /// ## Example /// ```no_run /// use async_std::prelude::*; /// use async_attributes; /// /// #[async_attributes::main] /// async fn main() -> cacache::Result<()> { /// let sri = cacache::write("./my-cache", "my-key", b"hello world").await?; /// cacache::copy_hash("./my-cache", &sri, "./data.txt").await?; /// Ok(()) /// } /// ``` pub async fn copy_hash<P, Q>(cache: P, sri: &Integrity, to: Q) -> Result<u64> where P: AsRef<Path>, Q: AsRef<Path>, { read::copy_async(cache.as_ref(), sri, to.as_ref()).await } /// Gets the metadata entry for a certain key. /// /// Note that the existence of a metadata entry is not a guarantee that the /// underlying data exists, since they are stored and managed independently. /// To verify that the underlying associated data exists, use `exists()`. pub async fn metadata<P, K>(cache: P, key: K) -> Result<Option<Metadata>> where P: AsRef<Path>, K: AsRef<str>, { Ok(index::find_async(cache.as_ref(), key.as_ref()).await?) } /// Returns true if the given hash exists in the cache. pub async fn exists<P: AsRef<Path>>(cache: P, sri: &Integrity) -> bool { read::has_content_async(cache.as_ref(), &sri) .await .is_some() } // --------------- // Synchronous API // --------------- /// File handle for reading data synchronously. /// /// Make sure to call `get.check()` when done reading /// to verify that the extracted data passes integrity /// verification. pub struct SyncReader { reader: read::Reader, } impl std::io::Read for SyncReader { fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> { self.reader.read(buf) } } impl SyncReader { /// Checks that data read from disk passes integrity checks. Returns the /// algorithm that was used verified the data. Should be called only after /// all data has been read from disk. /// /// ## Example /// ```no_run /// use std::io::Read; /// /// fn main() -> cacache::Result<()> { /// let mut fd = cacache::SyncReader::open("./my-cache", "my-key")?; /// let mut str = String::new(); /// fd.read_to_string(&mut str).expect("Failed to read to string"); /// // Remember to check that the data you got was correct! /// fd.check()?; /// Ok(()) /// } /// ``` pub fn check(self) -> Result<Algorithm> { self.reader.check() } /// Opens a new synchronous file handle into the cache, looking it up in the /// index using `key`. /// /// ## Example /// ```no_run /// use std::io::Read; /// /// fn main() -> cacache::Result<()> { /// let mut fd = cacache::SyncReader::open("./my-cache", "my-key")?; /// let mut str = String::new(); /// fd.read_to_string(&mut str).expect("Failed to parse string"); /// // Remember to check that the data you got was correct! /// fd.check()?; /// Ok(()) /// } /// ``` pub fn open<P, K>(cache: P, key: K) -> Result<SyncReader> where P: AsRef<Path>, K: AsRef<str>, { if let Some(entry) = index::find(cache.as_ref(), key.as_ref())? { SyncReader::open_hash(cache, entry.integrity) } else { Err(Error::EntryNotFound( cache.as_ref().to_path_buf(), key.as_ref().into(), ))? } } /// Opens a new synchronous file handle into the cache, based on its integrity address. /// /// ## Example /// ```no_run /// use std::io::Read; /// /// fn main() -> cacache::Result<()> { /// let sri = cacache::write_sync("./my-cache", "key", b"hello world")?; /// let mut fd = cacache::SyncReader::open_hash("./my-cache", sri)?; /// let mut str = String::new(); /// fd.read_to_string(&mut str).expect("Failed to read to string"); /// // Remember to check that the data you got was correct! /// fd.check()?; /// Ok(()) /// } /// ``` pub fn open_hash<P>(cache: P, sri: Integrity) -> Result<SyncReader> where P: AsRef<Path>, { Ok(SyncReader { reader: read::open(cache.as_ref(), sri)?, }) } } /// Reads the entire contents of a cache file synchronously into a bytes /// vector, looking the data up by key. /// /// ## Example /// ```no_run /// use std::io::Read; /// /// fn main() -> cacache::Result<()> { /// let data = cacache::read_sync("./my-cache", "my-key")?; /// Ok(()) /// } /// ``` pub fn read_sync<P, K>(cache: P, key: K) -> Result<Vec<u8>> where P: AsRef<Path>, K: AsRef<str>, { if let Some(entry) = index::find(cache.as_ref(), key.as_ref())? { read_hash_sync(cache, &entry.integrity) } else { Err(Error::EntryNotFound( cache.as_ref().to_path_buf(), key.as_ref().into(), ))? } } /// Reads the entire contents of a cache file synchronously into a bytes /// vector, looking the data up by its content address. /// /// ## Example /// ```no_run /// use std::io::Read; /// /// fn main() -> cacache::Result<()> { /// let sri = cacache::write_sync("./my-cache", "my-key", b"hello")?; /// let data = cacache::read_hash_sync("./my-cache", &sri)?; /// Ok(()) /// } /// ``` pub fn read_hash_sync<P>(cache: P, sri: &Integrity) -> Result<Vec<u8>> where P: AsRef<Path>, { Ok(read::read(cache.as_ref(), sri)?) } /// Copies a cache entry by key to a specified location. Returns the number of /// bytes copied. /// /// ## Example /// ```no_run /// use std::io::Read; /// /// fn main() -> cacache::Result<()> { /// cacache::copy_sync("./my-cache", "my-key", "./my-hello.txt")?; /// Ok(()) /// } /// ``` pub fn copy_sync<P, K, Q>(cache: P, key: K, to: Q) -> Result<u64> where P: AsRef<Path>, K: AsRef<str>, Q: AsRef<Path>, { if let Some(entry) = index::find(cache.as_ref(), key.as_ref())? { copy_hash_sync(cache, &entry.integrity, to) } else { Err(Error::EntryNotFound( cache.as_ref().to_path_buf(), key.as_ref().into(), ))? } } /// Copies a cache entry by integrity address to a specified location. Returns /// the number of bytes copied. /// /// ## Example /// ```no_run /// use std::io::Read; /// /// fn main() -> cacache::Result<()> { /// let sri = cacache::write_sync("./my-cache", "my-key", b"hello")?; /// cacache::copy_hash_sync("./my-cache", &sri, "./my-hello.txt")?; /// Ok(()) /// } /// ``` pub fn copy_hash_sync<P, Q>(cache: P, sri: &Integrity, to: Q) -> Result<u64> where P: AsRef<Path>, Q: AsRef<Path>, { read::copy(cache.as_ref(), sri, to.as_ref()) } /// Gets metadata for a certain key. /// /// Note that the existence of a metadata entry is not a guarantee that the /// underlying data exists, since they are stored and managed independently. /// To verify that the underlying associated data exists, use `exists_sync()`. pub fn metadata_sync<P, K>(cache: P, key: K) -> Result<Option<Metadata>> where P: AsRef<Path>, K: AsRef<str>, { Ok(index::find(cache.as_ref(), key.as_ref())?) } /// Returns true if the given hash exists in the cache. pub fn exists_sync<P: AsRef<Path>>(cache: P, sri: &Integrity) -> bool { read::has_content(cache.as_ref(), &sri).is_some() } #[cfg(test)] mod tests { use async_attributes; use async_std::fs as afs; use async_std::prelude::*; use std::fs; use tempfile; #[async_attributes::test] async fn test_open() { let tmp = tempfile::tempdir().unwrap(); let dir = tmp.path().to_owned(); crate::write(&dir, "my-key", b"hello world").await.unwrap(); let mut handle = crate::Reader::open(&dir, "my-key").await.unwrap(); let mut str = String::new(); handle.read_to_string(&mut str).await.unwrap(); handle.check().unwrap(); assert_eq!(str, String::from("hello world")); } #[async_attributes::test] async fn test_open_hash() { let tmp = tempfile::tempdir().unwrap(); let dir = tmp.path().to_owned(); let sri = crate::write(&dir, "my-key", b"hello world").await.unwrap(); let mut handle = crate::Reader::open_hash(&dir, sri).await.unwrap(); let mut str = String::new(); handle.read_to_string(&mut str).await.unwrap(); handle.check().unwrap(); assert_eq!(str, String::from("hello world")); } #[test] fn test_open_sync() { use std::io::prelude::*; let tmp = tempfile::tempdir().unwrap(); let dir = tmp.path().to_owned(); crate::write_sync(&dir, "my-key", b"hello world").unwrap(); let mut handle = crate::SyncReader::open(&dir, "my-key").unwrap(); let mut str = String::new(); handle.read_to_string(&mut str).unwrap(); handle.check().unwrap(); assert_eq!(str, String::from("hello world")); } #[test] fn test_open_hash_sync() { use std::io::prelude::*; let tmp = tempfile::tempdir().unwrap(); let dir = tmp.path().to_owned(); let sri = crate::write_sync(&dir, "my-key", b"hello world").unwrap(); let mut handle = crate::SyncReader::open_hash(&dir, sri).unwrap(); let mut str = String::new(); handle.read_to_string(&mut str).unwrap(); handle.check().unwrap(); assert_eq!(str, String::from("hello world")); } #[async_attributes::test] async fn test_read() { let tmp = tempfile::tempdir().unwrap(); let dir = tmp.path().to_owned(); crate::write(&dir, "my-key", b"hello world").await.unwrap(); let data = crate::read(&dir, "my-key").await.unwrap(); assert_eq!(data, b"hello world"); } #[async_attributes::test] async fn test_read_hash() { let tmp = tempfile::tempdir().unwrap(); let dir = tmp.path().to_owned(); let sri = crate::write(&dir, "my-key", b"hello world").await.unwrap(); let data = crate::read_hash(&dir, &sri).await.unwrap(); assert_eq!(data, b"hello world"); } #[test] fn test_read_sync() { let tmp = tempfile::tempdir().unwrap(); let dir = tmp.path().to_owned(); crate::write_sync(&dir, "my-key", b"hello world").unwrap(); let data = crate::read_sync(&dir, "my-key").unwrap(); assert_eq!(data, b"hello world"); } #[test] fn test_read_hash_sync() { let tmp = tempfile::tempdir().unwrap(); let dir = tmp.path().to_owned(); let sri = crate::write_sync(&dir, "my-key", b"hello world").unwrap(); let data = crate::read_hash_sync(&dir, &sri).unwrap(); assert_eq!(data, b"hello world"); } #[async_attributes::test] async fn test_copy() { let tmp = tempfile::tempdir().unwrap(); let dir = tmp.path(); let dest = dir.join("data"); crate::write(&dir, "my-key", b"hello world").await.unwrap(); crate::copy(&dir, "my-key", &dest).await.unwrap(); let data = afs::read(&dest).await.unwrap(); assert_eq!(data, b"hello world"); } #[async_attributes::test] async fn test_copy_hash() { let tmp = tempfile::tempdir().unwrap(); let dir = tmp.path(); let dest = dir.join("data"); let sri = crate::write(&dir, "my-key", b"hello world").await.unwrap(); crate::copy_hash(&dir, &sri, &dest).await.unwrap(); let data = afs::read(&dest).await.unwrap(); assert_eq!(data, b"hello world"); } #[test] fn test_copy_sync() { let tmp = tempfile::tempdir().unwrap(); let dir = tmp.path(); let dest = dir.join("data"); crate::write_sync(&dir, "my-key", b"hello world").unwrap(); crate::copy_sync(&dir, "my-key", &dest).unwrap(); let data = fs::read(&dest).unwrap(); assert_eq!(data, b"hello world"); } #[test] fn test_copy_hash_sync() { let tmp = tempfile::tempdir().unwrap(); let dir = tmp.path(); let dest = dir.join("data"); let sri = crate::write_sync(&dir, "my-key", b"hello world").unwrap(); crate::copy_hash_sync(&dir, &sri, &dest).unwrap(); let data = fs::read(&dest).unwrap(); assert_eq!(data, b"hello world"); } }