Use Result<Option<_>, _>

google-apis-common/src/auth.rs

@@ -27,17 +27,17 @@
 //! use core::future::Future;
 //! use core::pin::Pin;
 //!
-//! use google_apis_common::GetToken;
+//! use google_apis_common::{GetToken, oauth2};
 //!
 //! use http::Uri;
 //! use hyper::client::connect::Connection;
 //! use tokio::io::{AsyncRead, AsyncWrite};
 //! use tower_service::Service;
-//! use yup_oauth2::authenticator::Authenticator;
+//! use oauth2::authenticator::Authenticator;
 //!
 //! #[derive(Clone)]
 //! struct AuthenticatorWithRetry<S> {
-//!     auth: yup_oauth2::authenticator::Authenticator<S>,
+//!     auth: Authenticator<S>,
 //!     retries: usize,
 //! }
 //!
@@ -51,13 +51,16 @@
 //!     fn get_token<'a>(
 //!         &'a self,
 //!         scopes: &'a [&str],
-//!     ) -> Pin<Box<dyn Future<Output = Option<String>> + Send + 'a>> {
+//!     ) -> Pin<Box<dyn Future<Output = Result<Option<String>, Box<dyn std::error::Error + Send + Sync>>> + Send + 'a>> {
 //!         Box::pin(async move {
-//!             let mut auth_token = None;
+//!             let mut auth_token = Ok(None);
 //!             for _ in 0..self.retries {
-//!                 if let Ok(token) = self.auth.token(scopes).await {
-//!                     auth_token.insert(token.as_str().to_owned());
-//!                     break;
+//!                 match self.auth.token(scopes).await {
+//!                     Ok(token) => {
+//!                         auth_token = Ok(Some(token.as_str().to_owned()));
+//!                         break;
+//!                     },
+//!                     Err(e) => auth_token = Err(e.into()),
 //!                 }
 //!             }
 //!             auth_token
@@ -71,7 +74,7 @@
 use std::future::Future;
 use std::pin::Pin;
 
-type TokenResult = Option<String>;
+type TokenResult = Result<Option<String>, Box<dyn std::error::Error + Send + Sync>>;
 
 pub trait GetToken: GetTokenClone + Send + Sync {
     /// Called whenever an API call require authentication via an oauth2 token.
@@ -79,9 +82,7 @@ pub trait GetToken: GetTokenClone + Send + Sync {
     fn get_token<'a>(
         &'a self,
         _scopes: &'a [&str],
-    ) -> Pin<Box<dyn Future<Output = TokenResult> + Send + 'a>> {
-        Box::pin(async move { None })
-    }
+    ) -> Pin<Box<dyn Future<Output = TokenResult> + Send + 'a>>;
 }
 
 pub trait GetTokenClone {
@@ -108,7 +109,7 @@ impl GetToken for String {
         &'a self,
         _scopes: &'a [&str],
     ) -> Pin<Box<dyn Future<Output = TokenResult> + Send + 'a>> {
-        Box::pin(async move { Some(self.clone()) })
+        Box::pin(async move { Ok(Some(self.clone())) })
     }
 }
 
@@ -117,7 +118,14 @@ impl GetToken for String {
 #[derive(Default, Clone)]
 pub struct NoToken;
 
-impl GetToken for NoToken {}
+impl GetToken for NoToken {
+    fn get_token<'a>(
+        &'a self,
+        _scopes: &'a [&str],
+    ) -> Pin<Box<dyn Future<Output = TokenResult> + Send + 'a>> {
+        Box::pin(async move { Ok(None) })
+    }
+}
 
 #[cfg(feature = "yup-oauth2")]
 mod yup_oauth2_impl {
@@ -143,7 +151,12 @@ mod yup_oauth2_impl {
             &'a self,
             scopes: &'a [&str],
         ) -> Pin<Box<dyn Future<Output = TokenResult> + Send + 'a>> {
-            Box::pin(async move { self.token(scopes).await.ok().map(|t| t.as_str().to_owned()) })
+            Box::pin(async move {
+                self.token(scopes)
+                    .await
+                    .map(|t| Some(t.as_str().to_owned()))
+                    .map_err(|e| e.into())
+            })
         }
     }
 }

google-apis-common/src/lib.rs

@@ -114,14 +114,16 @@ pub trait Delegate: Send {
         None
     }
 
-    // TODO: Remove oauth2::Error
     /// Called whenever the Authenticator didn't yield a token. The delegate
     /// may attempt to provide one, or just take it as a general information about the
     /// impending failure.
     /// The given Error provides information about why the token couldn't be acquired in the
     /// first place
-    fn token(&mut self) -> Option<String> {
-        None
+    fn token(
+        &mut self,
+        e: Box<dyn StdError + Send + Sync>,
+    ) -> std::result::Result<Option<String>, Box<dyn StdError + Send + Sync>> {
+        Err(e)
     }
 
     /// Called during resumable uploads to provide a URL for the impending upload.
@@ -237,7 +239,7 @@ pub enum Error {
     MissingAPIKey,
 
     /// We required a Token, but didn't get one from the Authenticator
-    MissingToken,
+    MissingToken(Box<dyn StdError + Send + Sync>),
 
     /// The delgate instructed to cancel the operation
     Cancelled,
@@ -258,10 +260,10 @@ pub enum Error {
 
 impl Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        match *self {
-            Error::Io(ref err) => err.fmt(f),
-            Error::HttpError(ref err) => err.fmt(f),
-            Error::UploadSizeLimitExceeded(ref resource_size, ref max_size) => writeln!(
+        match self {
+            Error::Io(err) => err.fmt(f),
+            Error::HttpError(err) => err.fmt(f),
+            Error::UploadSizeLimitExceeded(resource_size, max_size) => writeln!(
                 f,
                 "The media size {} exceeds the maximum allowed upload size of {}",
                 resource_size, max_size
@@ -276,16 +278,16 @@ impl Display for Error {
                     "It is used as there are no Scopes defined for this method."
                 )
             }
-            Error::BadRequest(ref message) => writeln!(f, "Bad Request: {}", message),
-            Error::MissingToken => writeln!(f, "Token retrieval failed"),
+            Error::BadRequest(message) => writeln!(f, "Bad Request: {}", message),
+            Error::MissingToken(e) => writeln!(f, "Token retrieval failed: {}", e),
             Error::Cancelled => writeln!(f, "Operation cancelled by delegate"),
             Error::FieldClash(field) => writeln!(
                 f,
                 "The custom parameter '{}' is already provided natively by the CallBuilder.",
                 field
             ),
-            Error::JsonDecodeError(ref json_str, ref err) => writeln!(f, "{}: {}", err, json_str),
-            Error::Failure(ref response) => {
+            Error::JsonDecodeError(json_str, err) => writeln!(f, "{}: {}", err, json_str),
+            Error::Failure(response) => {
                 writeln!(f, "Http status indicates failure: {:?}", response)
             }
         }
@@ -577,14 +579,12 @@ impl RangeResponseHeader {
 pub struct ResumableUploadHelper<'a, A: 'a, S>
 where
     S: tower_service::Service<Uri> + Clone + Send + Sync + 'static,
-    S::Response: hyper::client::connect::Connection + AsyncRead + AsyncWrite + Send + Unpin + 'static,
+    S::Response:
+        hyper::client::connect::Connection + AsyncRead + AsyncWrite + Send + Unpin + 'static,
     S::Future: Send + Unpin + 'static,
     S::Error: Into<Box<dyn StdError + Send + Sync>>,
 {
-    pub client: &'a hyper::client::Client<
-        S,
-        hyper::body::Body,
-    >,
+    pub client: &'a hyper::client::Client<S, hyper::body::Body>,
     pub delegate: &'a mut dyn Delegate,
     pub start_at: Option<u64>,
     pub auth: &'a A,
@@ -598,7 +598,8 @@ where
 impl<'a, A, S> ResumableUploadHelper<'a, A, S>
 where
     S: tower_service::Service<Uri> + Clone + Send + Sync + 'static,
-    S::Response: hyper::client::connect::Connection + AsyncRead + AsyncWrite + Send + Unpin + 'static,
+    S::Response:
+        hyper::client::connect::Connection + AsyncRead + AsyncWrite + Send + Unpin + 'static,
     S::Future: Send + Unpin + 'static,
     S::Error: Into<Box<dyn StdError + Send + Sync>>,
 {