Implemented ChunkedFile

src/fsys/file.rs

@@ -14,6 +14,10 @@ GNU Affero General Public License for more details.
 */
 
 use crate::util::error::Error;
+use std::io::SeekFrom;
+use std::io::Seek;
+use std::io::Write;
+use std::io::Read;
 
 pub struct ChunkedFile {
     pub size: u128,
@@ -23,19 +27,66 @@ pub struct ChunkedFile {
 }
 
 impl ChunkedFile {
-    pub fn new(path: &std::path::Path, chunksize: u128) -> Result<ChunkedFile, Error> {
+    fn empty() -> ChunkedFile {
+        return ChunkedFile{
+            size: 0,
+            chunk_size: 0,
+            chunks_amount: 0,
+            path: std::path::PathBuf::new(),
+        }
+    }
+
+    /// Create a new, ready-to-write chunked regular file
+    pub fn new(path: &std::path::Path, size: u128, chunk_size: u128) -> Result<ChunkedFile, Error> {
+        let file_handle: std::fs::File;
+        match std::fs::File::create(path) {
+            Ok(fh) => {
+                file_handle = fh;
+            }
+        
+            Err(error) => {
+                return Err(
+                    Error::new(format!("{}", error).as_str())
+                );
+            }
+        }
+
+        let mut new_chunked_file: ChunkedFile = ChunkedFile::empty();
+
+        // path
+        new_chunked_file.path = path.to_path_buf();
+
+        // resize file 
+        match file_handle.set_len(size as u64) {
+            Ok(()) => {}
+            Err(error) => {
+                return Err(
+                    Error::new(format!("could not resize \'{}\': {}", path.display(), error).as_str())
+                );
+            }
+        }
+        new_chunked_file.size = size;
+
+        // chunks
+        new_chunked_file.chunk_size = chunk_size;
+        if new_chunked_file.size % chunk_size != 0 {
+            new_chunked_file.chunks_amount = (new_chunked_file.size / chunk_size) + 1;
+        } else {
+            new_chunked_file.chunks_amount = new_chunked_file.size / chunk_size;
+        }
+
+        return Ok(new_chunked_file);
+    }
+
+    /// Create a new, ready-to-read chunked file from already existing regular file
+    pub fn from(path: &std::path::Path, chunk_size: u128) -> Result<ChunkedFile, Error> {
         if !path.is_file() {
             return Err(
                 Error::new(format!("\'{}\' does not exist or not a regular file", path.display()).as_str())
             );
         }
         
-        let mut new_chunked_file: ChunkedFile = ChunkedFile{
-            size: 0,
-            chunk_size: 0,
-            chunks_amount: 0,
-            path: std::path::Path::new("").to_path_buf(),
-        };
+        let mut new_chunked_file: ChunkedFile = ChunkedFile::empty();
         
         // path
         new_chunked_file.path = path.to_path_buf();
@@ -53,17 +104,98 @@ impl ChunkedFile {
         }
 
         // chunks
-        new_chunked_file.chunk_size = chunksize;
-        new_chunked_file.chunks_amount = (new_chunked_file.size as f32 / chunksize as f32).ceil() as u128;
+        new_chunked_file.chunk_size = chunk_size;
+        if new_chunked_file.size % chunk_size != 0 {
+            new_chunked_file.chunks_amount = (new_chunked_file.size / chunk_size) + 1;
+        } else {
+            new_chunked_file.chunks_amount = new_chunked_file.size / chunk_size;
+        }
 
         return Ok(new_chunked_file);
     }
 
-    pub fn read_chunk(&self, buf: &[u8], chunk_no: u128) -> Option<Error> {
+    pub fn read_chunk(&self, buf: &mut [u8], chunk_no: u128) -> Option<Error> {
+        if chunk_no > self.chunks_amount {
+            return Some(Error::new("chunk number is bigger than there are chunks"));
+        }
+        
+        if (buf.len() as u128) < self.chunk_size {
+            return Some(Error::new("buffer is too small to fit a chunk"));
+        }
+
+        // open underlying file
+        let mut file_handle: std::fs::File;
+        match std::fs::File::open(&self.path) {
+            Ok(fh) => {
+                file_handle = fh;
+            }
+            Err(error) => {
+                return Some(Error::new(format!("{}", error).as_str()));
+            }
+        }
+        
+        // set position and read
+        let chunk_start_pos: u128 = self.chunk_size * chunk_no;
+        match file_handle.seek(SeekFrom::Start(chunk_start_pos as u64)) {
+            Ok(_) => {}
+            Err(error) => {
+                return Some(Error::new(format!("seek error: {}", error).as_str()))
+            }
+        }
+
+        match file_handle.read(buf) {
+            Ok(_) => {}
+            Err(error) => {
+                return Some(Error::new(format!("read error: {}", error).as_str()))
+            }
+        }
+
         return None;
     }
 
-    pub fn write_chunk(&mut self, chunk: &[u8] ,chunk_no: u128) -> Option<Error> {
+    pub fn write_chunk(&mut self, chunk: &[u8], chunk_no: u128) -> Option<Error> {
+        if chunk_no > self.chunks_amount {
+            // can't write outsize of pre-determined boundaries of a file !
+            return Some(Error::new("chunk number is bigger than there are chunks")); 
+        }
+
+        if (chunk.len() as u128) < self.chunk_size && chunk_no != self.chunks_amount {
+            // unfull chunk in the middle of a file
+            return Some(Error::new("cannot write unfull chunk in a not last position"));
+        }
+
+        if (chunk.len() as u128) > self.chunk_size {
+            // too big chunk
+            return Some(Error::new("chunk is too big"));
+        }
+
+        // open file and write a new chunk
+        let mut file_handle: std::fs::File;
+        match std::fs::File::options().truncate(false).write(true).create(true).open(&self.path) {
+            Ok(file) => {
+                file_handle = file;
+            }
+
+            Err(error) => {
+                return Some(Error::new(format!("{}", error).as_str()));
+            }
+        }
+
+        let chunk_start_pos: u128 = self.chunk_size * chunk_no;
+        match file_handle.seek(SeekFrom::Start(chunk_start_pos as u64)) {
+            Ok(_) => {}
+            Err(error) => {
+                return Some(Error::new(format!("seek error: {}", error).as_str()));
+            }
+        }
+        
+        match file_handle.write_all(chunk) {
+            Ok(()) => {}
+            Err(error) => {
+                return Some(Error::new(format!("write error: {}", error).as_str()))
+            }
+        }
+
         return None;
     }
 }

src/nodes/mod.rs

@@ -0,0 +1 @@
+pub mod node;

src/protocol/packets.rs

@@ -110,7 +110,7 @@ impl FileInfoPacket {
         };
     }
 
-    pub fn new(file: ChunkedFile, file_id: u128, rel_path: String) -> Result<FileInfoPacket, Error> {
+    pub fn new(file: &ChunkedFile, file_id: u128, rel_path: String) -> Result<FileInfoPacket, Error> {
         let mut new_fileinfo_packet: FileInfoPacket = FileInfoPacket::empty();
         
         // id
@@ -175,6 +175,12 @@ impl Packet for FileInfoPacket {
     }
 
     fn from_bytes(&mut self, packet_bytes: Vec<u8>) -> Option<Error> {
+        if packet_bytes.len() < 16+16+16+16+1+1 {
+            return Some(
+                Error::new(format!("{} bytes is too small for a fileinfo packet to be valid", packet_bytes.len()).as_str()
+            ));
+        }
+
         // file id
         self.file_id = read_u128_slice(&packet_bytes[0..16]);
 
@@ -236,6 +242,12 @@ impl Packet for FileDataPacket {
     }
 
     fn from_bytes(&mut self, packet_bytes: Vec<u8>) -> Option<Error> {
+        if packet_bytes.len() < 16+16+16+1 {
+            return Some(
+                Error::new(format!("{} bytes is too small for a fileinfo packet to be valid", packet_bytes.len()).as_str()
+            ));
+        }
+
         // file id
         self.file_id = read_u128_slice(&packet_bytes[0..16]);