feat(rust/signed-doc): add Builder type for signed documents

Author: saibatizoku

rust/signed_doc/src/builder.rs

@@ -0,0 +1,64 @@
+//! Catalyst Signed Document Builder.
+use crate::{CatalystSignedDocument, Content, InnerCatalystSignedDocument, Metadata, Signatures};
+
+/// Catalyst Signed Document Builder.
+#[derive(Debug, Default)]
+#[allow(dead_code)]
+pub struct Builder {
+    /// Document Metadata
+    metadata: Option<Metadata>,
+    /// Document Content
+    content: Option<Content>,
+    /// Signatures
+    signatures: Option<Signatures>,
+}
+
+impl Builder {
+    /// Start building a signed document
+    #[must_use]
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Set document metadata
+    #[must_use]
+    pub fn metadata(mut self, metadata: Metadata) -> Self {
+        self.metadata = Some(metadata);
+        self
+    }
+
+    /// Set document content
+    #[must_use]
+    pub fn content(mut self, content: Content) -> Self {
+        self.content = Some(content);
+        self
+    }
+
+    /// Set document signatures
+    #[must_use]
+    pub fn signatures(mut self, signatures: Signatures) -> Self {
+        self.signatures = Some(signatures);
+        self
+    }
+
+    /// Build a signed document
+    ///
+    /// ## Errors
+    ///
+    /// Returns
+    pub fn build(self) -> anyhow::Result<CatalystSignedDocument> {
+        match (self.metadata, self.content, self.signatures) {
+            (Some(metadata), Some(content), Some(signatures)) => {
+                Ok(CatalystSignedDocument {
+                    inner: InnerCatalystSignedDocument {
+                        metadata,
+                        content,
+                        signatures,
+                    }
+                    .into(),
+                })
+            },
+            _ => Err(anyhow::anyhow!("Failed to build Catalyst Signed Document")),
+        }
+    }
+}

rust/signed_doc/src/lib.rs

@@ -1,5 +1,6 @@
 //! Catalyst documents signing crate
 
+mod builder;
 mod content;
 mod error;
 mod metadata;
@@ -12,6 +13,7 @@ use std::{
 };
 
 use anyhow::anyhow;
+pub use builder::Builder;
 use content::Content;
 use coset::CborSerializable;
 pub use metadata::{AdditionalFields, DocumentRef, Metadata, UuidV7};
@@ -35,7 +37,7 @@ struct InnerCatalystSignedDocument {
 /// non-optional.
 pub struct CatalystSignedDocument {
     /// Catalyst Signed Document metadata, raw doc, with content errors.
-    inner: Arc<InnerCatalystSignedDocument>,
+    pub(crate) inner: Arc<InnerCatalystSignedDocument>,
 }
 
 impl Display for CatalystSignedDocument {