Add errors for tile loading

libs/vector_tile/src/error.rs

@@ -0,0 +1,21 @@
+use std::io;
+use protobuf::ProtobufError;
+
+#[derive(Debug)]
+pub enum Error {
+    Generic(String),
+    Protobuf(ProtobufError),
+    IO(io::Error),
+}
+
+impl From<ProtobufError> for Error {
+    fn from(err: ProtobufError) -> Self {
+        Error::Protobuf(err)
+    }
+}
+
+impl From<io::Error> for Error {
+    fn from(err: io::Error) -> Self {
+        Error::IO(err)
+    }
+}

libs/vector_tile/src/lib.rs

@@ -1,11 +1,12 @@
 use std::fs::File;
 use std::io;
-use std::io::{BufReader, Read};
+use std::io::{BufRead, BufReader, Read};
 use std::path::{Path};
 
 use protobuf::Message;
 
 use crate::encoding::Decode;
+use crate::error::Error;
 use crate::protos::vector_tile::Tile as TileProto;
 use crate::tile::Tile;
 
@@ -18,15 +19,19 @@ mod tests;
 pub mod geometry;
 pub mod tile;
 pub mod grid;
+pub mod error;
 
-pub fn parse_tile<P: AsRef<Path>>(path: P) -> io::Result<Tile> {
+pub fn parse_tile<P: AsRef<Path>>(path: P) -> Result<Tile, Error> {
     let mut f = File::open(path)?;
     let mut reader = BufReader::new(f);
-    return Ok(parse_tile_reader(&mut reader));
+    parse_tile_reader(&mut reader).into()
 }
 
-pub fn parse_tile_reader(reader: &mut dyn Read) -> Tile {
-    let proto_tile = TileProto::parse_from_reader(reader).unwrap();
-    return proto_tile.decode();
+pub fn parse_tile_reader<B: BufRead>(reader: &mut B) -> Result<Tile, Error> {
+   if reader.fill_buf()?.is_empty() {
+       return Err(Error::Generic("input must not be empty".to_string()));
+   }
+    let proto_tile = TileProto::parse_from_reader(reader)?;
+    Ok(proto_tile.decode())
 }
 

libs/vector_tile/src/tests.rs

@@ -1,11 +1,11 @@
 use std::fs::File;
-use std::io::BufReader;
+use std::io::{BufReader, Cursor};
 
 use protobuf::Message;
 
 use crate::encoding::Decode;
-use crate::grid::{GOOGLE_MERCATOR, tile_coordinates_bavaria};
-use crate::parse_tile;
+use crate::grid::{google_mercator, tile_coordinates_bavaria};
+use crate::{parse_tile, parse_tile_reader};
 use crate::protos::vector_tile::Tile;
 
 #[test]
@@ -15,5 +15,10 @@ fn test_parsing_europe_pbf() {
 
 #[test]
 fn test_tile_coordinates_bavaria() {
-    println!("{:?}", tile_coordinates_bavaria(&GOOGLE_MERCATOR, 6));
+    println!("{:?}", tile_coordinates_bavaria(&google_mercator(), 6));
 }
+
+#[test]
+fn test_empty_fail() {
+    assert!(parse_tile_reader(&mut Cursor::new(&[])).is_err())
+}