Auto merge of #11993 - epage:member, r=weihanglo

fix: Allow win/mac credential managers to build on all platforms

### What does this PR try to resolve?

This is a step towards #11987 by making two of the platform-specific credential managers build on all platforms using `cfg`.

I haven't done `gnome-secret` yet because that is more of an oddball in that it isn't just platforms-specific but dependent on what is installed on that platform.

### How should we test and review this PR?

```console
$ cargo check --workspace --exclude cargo-credential-gnome-secret
```

Note that the commits are broken down so you can view the movements of code separate from the functionality being changed.

### Additional information

Other information you want to mention in this PR, such as prior arts,
future extensions, an unresolved problem, or a TODO list.
-->
<!-- homu-ignore:end -->

crates/credential/cargo-credential-macos-keychain/src/main.rs

@@ -1,18 +1,20 @@
 //! Cargo registry macos keychain credential process.
 
-use cargo_credential::{Credential, Error};
-use security_framework::os::macos::keychain::SecKeychain;
+#[cfg(target_os = "macos")]
+mod macos {
+    use cargo_credential::{Credential, Error};
+    use security_framework::os::macos::keychain::SecKeychain;
 
-struct MacKeychain;
+    pub(crate) struct MacKeychain;
 
-/// The account name is not used.
-const ACCOUNT: &'static str = "";
+    /// The account name is not used.
+    const ACCOUNT: &'static str = "";
 
-fn registry(registry_name: &str) -> String {
+    fn registry(registry_name: &str) -> String {
         format!("cargo-registry:{}", registry_name)
-}
+    }
 
-impl Credential for MacKeychain {
+    impl Credential for MacKeychain {
         fn name(&self) -> &'static str {
             env!("CARGO_PKG_NAME")
         }
@@ -43,8 +45,14 @@ impl Credential for MacKeychain {
             item.delete();
             Ok(())
         }
+    }
 }
 
+#[cfg(not(target_os = "macos"))]
+use cargo_credential::UnsupportedCredential as MacKeychain;
+#[cfg(target_os = "macos")]
+use macos::MacKeychain;
+
 fn main() {
     cargo_credential::main(MacKeychain);
 }

crates/credential/cargo-credential-wincred/src/main.rs

@@ -1,37 +1,39 @@
 //! Cargo registry windows credential process.
 
-use cargo_credential::{Credential, Error};
-use std::ffi::OsStr;
-use std::os::windows::ffi::OsStrExt;
+#[cfg(windows)]
+mod win {
+    use cargo_credential::{Credential, Error};
+    use std::ffi::OsStr;
+    use std::os::windows::ffi::OsStrExt;
 
-use windows_sys::core::PWSTR;
-use windows_sys::Win32::Foundation::ERROR_NOT_FOUND;
-use windows_sys::Win32::Foundation::FILETIME;
-use windows_sys::Win32::Foundation::TRUE;
-use windows_sys::Win32::Security::Credentials::CredDeleteW;
-use windows_sys::Win32::Security::Credentials::CredReadW;
-use windows_sys::Win32::Security::Credentials::CredWriteW;
-use windows_sys::Win32::Security::Credentials::CREDENTIALW;
-use windows_sys::Win32::Security::Credentials::CRED_PERSIST_LOCAL_MACHINE;
-use windows_sys::Win32::Security::Credentials::CRED_TYPE_GENERIC;
+    use windows_sys::core::PWSTR;
+    use windows_sys::Win32::Foundation::ERROR_NOT_FOUND;
+    use windows_sys::Win32::Foundation::FILETIME;
+    use windows_sys::Win32::Foundation::TRUE;
+    use windows_sys::Win32::Security::Credentials::CredDeleteW;
+    use windows_sys::Win32::Security::Credentials::CredReadW;
+    use windows_sys::Win32::Security::Credentials::CredWriteW;
+    use windows_sys::Win32::Security::Credentials::CREDENTIALW;
+    use windows_sys::Win32::Security::Credentials::CRED_PERSIST_LOCAL_MACHINE;
+    use windows_sys::Win32::Security::Credentials::CRED_TYPE_GENERIC;
 
-struct WindowsCredential;
+    pub(crate) struct WindowsCredential;
 
-/// Converts a string to a nul-terminated wide UTF-16 byte sequence.
-fn wstr(s: &str) -> Vec<u16> {
+    /// Converts a string to a nul-terminated wide UTF-16 byte sequence.
+    fn wstr(s: &str) -> Vec<u16> {
         let mut wide: Vec<u16> = OsStr::new(s).encode_wide().collect();
         if wide.iter().any(|b| *b == 0) {
             panic!("nul byte in wide string");
         }
         wide.push(0);
         wide
-}
+    }
 
-fn target_name(registry_name: &str) -> Vec<u16> {
+    fn target_name(registry_name: &str) -> Vec<u16> {
         wstr(&format!("cargo-registry:{}", registry_name))
-}
+    }
 
-impl Credential for WindowsCredential {
+    impl Credential for WindowsCredential {
         fn name(&self) -> &'static str {
             env!("CARGO_PKG_NAME")
         }
@@ -47,15 +49,18 @@ impl Credential for WindowsCredential {
                     p_credential as *mut _ as *mut _,
                 ) != TRUE
                 {
-                return Err(
-                    format!("failed to fetch token: {}", std::io::Error::last_os_error()).into(),
-                );
+                    return Err(format!(
+                        "failed to fetch token: {}",
+                        std::io::Error::last_os_error()
+                    )
+                    .into());
                 }
                 let bytes = std::slice::from_raw_parts(
                     (*p_credential).CredentialBlob,
                     (*p_credential).CredentialBlobSize as usize,
                 );
-            String::from_utf8(bytes.to_vec()).map_err(|_| "failed to convert token to UTF8".into())
+                String::from_utf8(bytes.to_vec())
+                    .map_err(|_| "failed to convert token to UTF8".into())
             }
         }
 
@@ -104,8 +109,14 @@ impl Credential for WindowsCredential {
             }
             Ok(())
         }
+    }
 }
 
+#[cfg(not(windows))]
+use cargo_credential::UnsupportedCredential as WindowsCredential;
+#[cfg(windows)]
+use win::WindowsCredential;
+
 fn main() {
     cargo_credential::main(WindowsCredential);
 }

crates/credential/cargo-credential/src/lib.rs

@@ -34,6 +34,26 @@ pub trait Credential {
     fn erase(&self, index_url: &str) -> Result<(), Error>;
 }
 
+pub struct UnsupportedCredential;
+
+impl Credential for UnsupportedCredential {
+    fn name(&self) -> &'static str {
+        "unsupported"
+    }
+
+    fn get(&self, _index_url: &str) -> Result<String, Error> {
+        Err("unsupported".into())
+    }
+
+    fn store(&self, _index_url: &str, _token: &str, _name: Option<&str>) -> Result<(), Error> {
+        Err("unsupported".into())
+    }
+
+    fn erase(&self, _index_url: &str) -> Result<(), Error> {
+        Err("unsupported".into())
+    }
+}
+
 /// Runs the credential interaction by processing the command-line and
 /// environment variables.
 pub fn main(credential: impl Credential) {