From 81c9fc8fe2c72b2b292c185bee9312d80643d959 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Orhun=20Parmaks=C4=B1z?= <orhunparmaksiz@gmail.com>
Date: Tue, 5 Oct 2021 20:32:52 +0300
Subject: [PATCH] feat(error): add custom error implementation

---
 Cargo.lock                | 23 +++++++++++++++++++++++
 kparams-core/Cargo.toml   |  1 +
 kparams-core/src/error.rs | 12 ++++++++++++
 kparams-core/src/lib.rs   |  3 +++
 kparams/src/lib.rs        | 23 +++++++++++++++++++++++
 kparams/src/main.rs       | 15 ++++-----------
 6 files changed, 66 insertions(+), 11 deletions(-)
 create mode 100644 kparams-core/src/error.rs
 create mode 100644 kparams/src/lib.rs

diff --git a/Cargo.lock b/Cargo.lock
index 54b60de..34825d3 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -70,6 +70,9 @@ dependencies = [
 [[package]]
 name = "kparams-core"
 version = "0.1.0"
+dependencies = [
+ "thiserror",
+]
 
 [[package]]
 name = "kparams-parser"
@@ -176,6 +179,26 @@ dependencies = [
  "unicode-xid",
 ]
 
+[[package]]
+name = "thiserror"
+version = "1.0.29"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "602eca064b2d83369e2b2f34b09c70b605402801927c65c11071ac911d299b88"
+dependencies = [
+ "thiserror-impl",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "1.0.29"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bad553cc2c78e8de258400763a647e80e6d1b31ee237275d756f6836d204494c"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "typenum"
 version = "1.14.0"
diff --git a/kparams-core/Cargo.toml b/kparams-core/Cargo.toml
index ea453f4..6c58314 100644
--- a/kparams-core/Cargo.toml
+++ b/kparams-core/Cargo.toml
@@ -5,3 +5,4 @@ authors = ["Orhun Parmaksız <orhunparmaksiz@gmail.com>"]
 edition = "2021"
 
 [dependencies]
+thiserror = "1.0.29"
diff --git a/kparams-core/src/error.rs b/kparams-core/src/error.rs
new file mode 100644
index 0000000..f0e6fa2
--- /dev/null
+++ b/kparams-core/src/error.rs
@@ -0,0 +1,12 @@
+use thiserror::Error as ThisError;
+
+/// Custom error type.
+#[derive(Debug, ThisError)]
+pub enum Error {
+    /// Error that might occur during I/O operations.
+    #[error("IO error: `{0}`")]
+    IoError(#[from] std::io::Error),
+}
+
+/// Type alias for the standard [`Result`] type.
+pub type Result<T> = core::result::Result<T, Error>;
diff --git a/kparams-core/src/lib.rs b/kparams-core/src/lib.rs
index 75a32b9..911e434 100644
--- a/kparams-core/src/lib.rs
+++ b/kparams-core/src/lib.rs
@@ -7,3 +7,6 @@ pub mod kernel;
 
 /// File reader.
 pub mod reader;
+
+/// Error handler.
+pub mod error;
diff --git a/kparams/src/lib.rs b/kparams/src/lib.rs
new file mode 100644
index 0000000..176e964
--- /dev/null
+++ b/kparams/src/lib.rs
@@ -0,0 +1,23 @@
+//! kparams
+
+#![warn(missing_docs, clippy::unwrap_used)]
+
+use kparams_core::error::Result;
+use kparams_core::reader;
+use kparams_parser::parser::RstParser;
+use std::path::PathBuf;
+
+/// Runs `kparams`.
+pub fn run() -> Result<()> {
+    let kernel_docs = PathBuf::from("/usr/share/doc/linux");
+    let sysctl_docs = kernel_docs.join("admin-guide").join("sysctl");
+    let kernel_section = reader::read_to_string(&sysctl_docs.join("kernel.rst"))?;
+
+    let kernel_section_docs = RstParser::parse_docs(&kernel_section);
+    for kernel_parameter in kernel_section_docs.parameters {
+        println!("## {}", kernel_parameter.name);
+        println!("{}", kernel_parameter.description);
+    }
+
+    Ok(())
+}
diff --git a/kparams/src/main.rs b/kparams/src/main.rs
index 54a15ed..b0636ee 100644
--- a/kparams/src/main.rs
+++ b/kparams/src/main.rs
@@ -1,15 +1,8 @@
-use kparams_core::reader;
-use kparams_parser::parser::RstParser;
-use std::path::PathBuf;
+use std::process;
 
 fn main() {
-    let kernel_docs = PathBuf::from("/usr/share/doc/linux");
-    let sysctl_docs = kernel_docs.join("admin-guide").join("sysctl");
-    let kernel_section = reader::read_to_string(&sysctl_docs.join("kernel.rst")).unwrap();
-
-    let kernel_section_docs = RstParser::parse_docs(&kernel_section);
-    for kernel_parameter in kernel_section_docs.parameters {
-        println!("## {}", kernel_parameter.name);
-        println!("{}", kernel_parameter.description);
+    match kparams::run() {
+        Ok(_) => process::exit(0),
+        Err(_) => process::exit(1),
     }
 }