add error code abstractions

meilisearch-error/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "meilisearch-error"
+version = "0.10.1"
+authors = ["mpostma <postma.marin@protonmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+actix-http = "1.0.1"

meilisearch-error/src/lib.rs

@@ -0,0 +1,122 @@
+#![allow(dead_code)]
+
+use std::fmt;
+use actix_http::http::StatusCode;
+
+pub trait ErrorCode: std::error::Error {
+    fn error_code(&self) -> Code;
+}
+
+enum ErrorCategory {
+   None = 0,
+}
+
+pub enum Code {
+    Other,
+}
+
+impl fmt::Display for Code {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.internal().fmt(f)
+    }
+}
+
+/// Internal structure providing a convenient way to create error codes
+struct ErrCode {
+    public: bool,
+    fatal: bool,
+    http_code: StatusCode,
+    category: ErrorCategory,
+    code: u16,
+}
+
+impl ErrCode {
+    fn new(
+        public: bool,
+        fatal: bool,
+        http_code: StatusCode,
+        category: ErrorCategory,
+        code: u16
+    ) -> ErrCode {
+        ErrCode {
+            public,
+            fatal,
+            http_code,
+            category,
+            code,
+        }
+    }
+
+    pub fn internal(
+        public: bool,
+        fatal: bool,
+        category: ErrorCategory,
+        code: u16
+        ) -> ErrCode {
+        ErrCode::new(public, fatal, StatusCode::INTERNAL_SERVER_ERROR, category, code)
+    }
+
+    pub fn forbidden(
+        public: bool,
+        fatal: bool,
+        category: ErrorCategory,
+        code: u16
+        ) -> ErrCode {
+        ErrCode::new(public, fatal, StatusCode::FORBIDDEN, category, code)
+    }
+
+    pub fn unauthorized(
+        public: bool,
+        fatal: bool,
+        category: ErrorCategory,
+        code: u16
+        ) -> ErrCode {
+        ErrCode::new(public, fatal, StatusCode::UNAUTHORIZED, category, code)
+    }
+
+    pub fn not_found(
+        public: bool,
+        fatal: bool,
+        category: ErrorCategory,
+        code: u16
+        ) -> ErrCode {
+        ErrCode::new(public, fatal, StatusCode::NOT_FOUND, category, code)
+    }
+}
+
+impl Code {
+
+    /// ascociate a `Code` variant to the actual ErrCode
+    fn err_code(&self) -> ErrCode {
+        use Code::*;
+
+        match self {
+            Other => ErrCode::not_found(false, false, ErrorCategory::None, 0),
+        }
+    }
+
+    /// return the HTTP status code ascociated with the `Code`
+    pub fn http(&self) -> StatusCode {
+        self.err_code().http_code
+    }
+
+    /// returns internal error code, in the form:
+    /// `EPFCNN`
+    /// - E: plain letter "E", to mark an error code, future main introduce W for warning
+    /// - P: scope of the error, 0 for private, 1 for public. Private are error that make no sense
+    /// reporting to the user, they are internal errors, and there is nothing the user can do about
+    /// them. they are nonetheless returned, without a message, for assistance purpose.
+    /// - F: 0 or 1, report if the error is fatal.
+    /// - C: error category, number in 0-9, the category of the error. Categories are still to be determined, input is required.
+    /// - NN: The error number, two digits, within C.
+
+
+    pub fn internal(&self) -> String {
+        let ErrCode { public, fatal, category, code, .. } = self.err_code();
+        format!("E{}{}{}{}",
+            public as u16,
+            fatal as u16,
+            category as u16,
+            code)
+    }
+}