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// Copyright 2016 Drew Short <drew@sothr.com>.
//
// Licensed under the MIT license<LICENSE-MIT or http://opensource.org/licenses/MIT>.
// This file may not be copied, modified, or distributed except according to those terms.
extern crate complex;
extern crate flate2;
extern crate image;
extern crate sha1;
use self::image::ImageBuffer;
use self::sha1::Sha1;
use self::flate2::Compression;
use self::flate2::write::ZlibEncoder;
use self::flate2::read::ZlibDecoder;
use std::str::FromStr;
use std::path::Path;
use std::fs::{File, create_dir_all, remove_dir_all};
use std::io::{Read, Error, Write};
use std::option::Option;
use std::result::Result;
use super::rustc_serialize::json;
pub const DEFAULT_CACHE_DIR: &'static str = "./.hash_cache";
const CACHED_IMAGE_EXT: &'static str = "png";
const CACHED_MATRIX_EXT: &'static str = "dft";
// Caching version information
const CACHE_VERSION: u32 = 1;
const CACHE_METADATA_FILE: &'static str = "cache.meta";
#[derive(RustcDecodable, RustcEncodable)]
struct CacheMetadata {
cache_version: u32,
}
impl Default for CacheMetadata {
fn default() -> CacheMetadata {
CacheMetadata { cache_version: CACHE_VERSION }
}
}
impl PartialEq<CacheMetadata> for CacheMetadata {
fn eq(&self, other: &CacheMetadata) -> bool {
self.cache_version == other.cache_version
}
fn ne(&self, other: &CacheMetadata) -> bool {
!self.eq(&other)
}
}
/**
* Structure to hold implementation of the cache
*/
pub struct Cache<'a> {
pub cache_dir: &'a str,
pub use_cache: bool,
}
impl<'a> Default for Cache<'a> {
fn default() -> Cache<'a> {
Cache {
cache_dir: DEFAULT_CACHE_DIR,
use_cache: true,
}
}
}
impl<'a> Cache<'a> {
/**
* Create the required directories for the cache
*/
pub fn init(&self) -> Result<(), Error> {
match create_dir_all(self.cache_dir) {
Ok(_) => {
let metadata_path_str = format!("{}/{}", self.cache_dir, CACHE_METADATA_FILE);
let metadata_path = Path::new(&metadata_path_str);
let current_metadata: CacheMetadata = Default::default();
match File::open(&metadata_path) {
Ok(mut file) => {
// Metadata file exists, compare them
let mut loaded_metadata_string = String::new();
match file.read_to_string(&mut loaded_metadata_string) {
Ok(_) => {
let loaded_metadata: CacheMetadata =
match json::decode(&loaded_metadata_string) {
Ok(data) => data,
Err(_) => CacheMetadata { cache_version: 0 },
};
// If they match, continue
if current_metadata != loaded_metadata {
// If they don't wipe the cache to start new
match remove_dir_all(self.cache_dir) {
Ok(_) => {
match create_dir_all(self.cache_dir) {
Ok(_) => (),
Err(e) => println!("Error: {}", e),
}
}
Err(e) => println!("Error: {}", e),
};
};
}
Err(e) => println!("Error: {}", e),
};
}
// Metadata file doesn't exist, do nothing assume all is well,
// create new metadata file
Err(_) => {}
};
let encoded_cache_metadata = json::encode(¤t_metadata).unwrap();
match File::create(&metadata_path) {
Ok(mut file) => {
let _ = file.write(&encoded_cache_metadata.as_bytes());
Ok(())
}
Err(e) => Err(e),
}
}
Err(e) => Err(e),
}
}
/**
* Clean the cache directory completely
*/
pub fn clean(&self) -> Result<(), Error> {
remove_dir_all(self.cache_dir)
}
/**
* Get the hash of the desired file and return it as a hex string
*/
pub fn get_file_hash(&self, path: &Path) -> Result<String, Error> {
let mut source = try!(File::open(&path));
let mut buf: Vec<u8> = Vec::new();
try!(source.read_to_end(&mut buf));
let mut sha1 = Sha1::new();
sha1.update(&buf);
// Return the hex result of the hash
Ok(sha1.hexdigest())
}
/**
* Put an image buffer in the cache
*/
pub fn put_image_in_cache(&self,
path: &Path,
size: u32,
image: &ImageBuffer<image::Luma<u8>, Vec<u8>>)
-> Result<bool, Error> {
let hash = self.get_file_hash(&path);
match hash {
Ok(sha1) => {
let cache_path_str = format!("{}/image/{}x{}/{}.{}",
self.cache_dir,
size,
size,
sha1,
CACHED_IMAGE_EXT);
let cache_dir_str = format!("{}/image/{}x{}", self.cache_dir, size, size);
match create_dir_all(cache_dir_str) {
Ok(_) => {
let cached_path = Path::new(&cache_path_str);
// Save the file into the cache
match image.save(cached_path) {
Ok(_) => {}
Err(e) => {
println!("Error: {}", e);
return Err(e);
}
}
}
Err(e) => println!("Error: {}", e),
}
}
Err(e) => {
println!("Error: {}", e);
return Err(e);
}
}
Ok(true)
}
/**
* Get an image buffer out of the cache
*/
pub fn get_image_from_cache(&self,
path: &Path,
size: u32)
-> Option<ImageBuffer<image::Luma<u8>, Vec<u8>>> {
if self.use_cache {
let hash = self.get_file_hash(&path);
match hash {
Ok(sha1) => {
// Check if the file exists in the cache
let cache_path_str = format!("{}/image/{}x{}/{}.{}",
self.cache_dir,
size,
size,
sha1,
CACHED_IMAGE_EXT);
let cached_path = Path::new(&cache_path_str);
// Try to open, if it does, then we can read the image in
match File::open(&cached_path) {
Ok(_) => {
let image = image::open(&cached_path).unwrap();
Some(image.to_luma())
}
// Don't really care here, it just means an existing cached
// file doesn't exist, or can't be read.
Err(_) => None,
}
}
Err(e) => {
println!("Error: {}", e);
None
}
}
} else {
None
}
}
/**
* Expects a slice of slices that represents lines in the file
*/
pub fn put_matrix_in_cache(&self,
path: &Path,
size: u32,
file_contents: &Vec<Vec<f64>>)
-> Result<bool, Error> {
let hash = self.get_file_hash(&path);
match hash {
Ok(sha1) => {
let cache_path_str = format!("{}/matrix/{}x{}/{}.{}",
self.cache_dir,
size,
size,
sha1,
CACHED_MATRIX_EXT);
let cache_dir_str = format!("{}/matrix/{}x{}", self.cache_dir, size, size);
match create_dir_all(cache_dir_str) {
Ok(_) => {
let cached_path = Path::new(&cache_path_str);
// Save the file into the cache
match File::create(&cached_path) {
Ok(mut file) => {
let mut compressor = ZlibEncoder::new(Vec::new(),
Compression::Default);
for row in file_contents {
let mut row_str = row.iter().fold(String::new(),
|acc, &item| {
acc +
&format!("{},", item)
});
// remove the last comma
let desire_len = row_str.len() - 1;
row_str.truncate(desire_len);
row_str.push_str("\n");
try!(compressor.write(&row_str.into_bytes()));
}
let compressed_matrix = match compressor.finish() {
Ok(data) => data,
Err(e) => {
println!("Unable to compress matrix data: {}", e);
return Err(e);
}
};
try!(file.write(&compressed_matrix));
try!(file.flush());
}
Err(e) => {
return Err(e);
}
}
}
Err(e) => println!("Error: {}", e),
}
}
Err(e) => {
println!("Error: {}", e);
return Err(e);
}
}
Ok(true)
}
/**
* Get a matrix out of the cache
*/
pub fn get_matrix_from_cache(&self, path: &Path, size: u32) -> Option<Vec<Vec<f64>>> {
if self.use_cache {
let hash = self.get_file_hash(&path);
match hash {
Ok(sha1) => {
// Check if the file exists in the cache
let cache_path_str = format!("{}/matrix/{}x{}/{}.{}",
self.cache_dir,
size,
size,
sha1,
CACHED_MATRIX_EXT);
let cached_path = Path::new(&cache_path_str);
// Try to open, if it does, then we can read the image in
match File::open(&cached_path) {
Ok(file) => {
let mut decoder = ZlibDecoder::new(&file);
let mut matrix_data_str = String::new();
match decoder.read_to_string(&mut matrix_data_str) {
Ok(_) => {}
Err(e) => {
println!("Unable to decompress matrix: {}", e);
return None;
}
};
// convert the matrix
let matrix: Vec<Vec<f64>> = matrix_data_str.trim()
.split("\n")
.map(|line| {
line.split(",")
.map(|f| {
f64::from_str(f)
.unwrap()
})
.collect()
})
.collect();
Some(matrix)
}
// Don't really care here, it just means an existing cached
// file doesn't exist, or can't be read.
Err(_) => None,
}
}
Err(e) => {
println!("Error: {}", e);
None
}
}
} else {
None
}
}
}
#[test]
fn test_get_file_hash() {
let target = "test_images/sample_01_large.jpg";
let target_path = Path::new(target);
let cache: Cache = Default::default();
let hash = cache.get_file_hash(&target_path);
match hash {
Ok(v) => {
println!("Hash: {}", v);
assert!(v == "4beb6f2d852b75a313863916a1803ebad13a3196");
}
Err(e) => {
println!("Error: {:?}", e);
assert!(false);
}
}
}
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