Load files

Cargo.lock

@@ -11,6 +11,12 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "anyhow"
+version = "1.0.45"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ee10e43ae4a853c0a3591d4e2ada1719e553be18199d9da9d4a83f5927c2f5c7"
+
 [[package]]
 name = "atty"
 version = "0.2.14"
@@ -62,6 +68,16 @@ dependencies = [
  "vec_map",
 ]
 
+[[package]]
+name = "codespan-reporting"
+version = "0.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3538270d33cc669650c4b093848450d380def10c331d38c768e34cac80576e6e"
+dependencies = [
+ "termcolor",
+ "unicode-width",
+]
+
 [[package]]
 name = "heck"
 version = "0.3.3"
@@ -194,6 +210,15 @@ dependencies = [
  "unicode-xid",
 ]
 
+[[package]]
+name = "termcolor"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2dfed899f0eb03f32ee8c6a0aabdb8a7949659e3466561fc0adf54e26d88c5f4"
+dependencies = [
+ "winapi-util",
+]
+
 [[package]]
 name = "textwrap"
 version = "0.11.0"
@@ -203,6 +228,26 @@ dependencies = [
  "unicode-width",
 ]
 
+[[package]]
+name = "thiserror"
+version = "1.0.30"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "854babe52e4df1653706b98fcfc05843010039b406875930a70e4d9644e5c417"
+dependencies = [
+ "thiserror-impl",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "1.0.30"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "aa32fd3f627f367fe16f893e2597ae3c05020f8bba2666a4e6ea73d377e5714b"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "time"
 version = "0.1.44"
@@ -218,8 +263,11 @@ dependencies = [
 name = "today"
 version = "0.1.0"
 dependencies = [
+ "anyhow",
  "chrono",
+ "codespan-reporting",
  "structopt",
+ "thiserror",
 ]
 
 [[package]]
@@ -274,6 +322,15 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
 
+[[package]]
+name = "winapi-util"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "70ec6ce85bb158151cae5e5c87f95a8e97d2c0c4b001223f33a334e3ce5de178"
+dependencies = [
+ "winapi",
+]
+
 [[package]]
 name = "winapi-x86_64-pc-windows-gnu"
 version = "0.4.0"

Cargo.toml

@@ -4,5 +4,8 @@ version = "0.1.0"
 edition = "2018"
 
 [dependencies]
+anyhow = "1.0.45"
 chrono = "0.4.19"
+codespan-reporting = "0.11.1"
 structopt = "0.3.25"
+thiserror = "1.0.30"

src/main.rs

@@ -3,6 +3,7 @@ use std::path::PathBuf;
 use structopt::StructOpt;
 
 mod commands;
+mod source;
 
 #[derive(Debug, StructOpt)]
 pub struct Opt {

src/source.rs

@@ -0,0 +1,64 @@
+use std::collections::HashMap;
+use std::ops::Range;
+use std::path::{Path, PathBuf};
+use std::{fs, io};
+
+use codespan_reporting::files::SimpleFiles;
+
+#[derive(Debug, thiserror::Error)]
+pub enum LoadFileError {
+    #[error("file already loaded")]
+    FileAlreadyLoaded,
+    #[error("error loading file: {0}")]
+    IoError(#[from] io::Error),
+}
+
+pub struct SourceFiles {
+    files: SimpleFiles<String, String>,
+    files_by_path: HashMap<PathBuf, usize>,
+}
+
+impl SourceFiles {
+    pub fn new() -> Self {
+        Self {
+            files: SimpleFiles::new(),
+            files_by_path: HashMap::new(),
+        }
+    }
+
+    pub fn load(&mut self, path: &Path) -> Result<SourceFile, LoadFileError> {
+        let canonical_path = path.canonicalize()?;
+        if self.files_by_path.contains_key(&canonical_path) {
+            return Err(LoadFileError::FileAlreadyLoaded);
+        }
+
+        let name = path.as_os_str().to_string_lossy().into_owned();
+        let content = fs::read_to_string(path)?;
+        let file_id = self.files.add(name, content);
+        Ok(SourceFile(file_id))
+    }
+
+    pub fn content_of(&self, file: SourceFile) -> Option<&str> {
+        self.files.get(file.0).ok().map(|sf| sf.source() as &str)
+    }
+}
+
+#[derive(Clone, Copy, Debug)]
+pub struct SourceFile(usize);
+
+impl SourceFile {
+    pub fn span(&self, range: Range<usize>) -> SourceSpan {
+        SourceSpan {
+            file: self.0,
+            start: range.start,
+            end: range.end,
+        }
+    }
+}
+
+#[derive(Clone, Copy, Debug)]
+pub struct SourceSpan {
+    file: usize,
+    start: usize,
+    end: usize,
+}