refactor: create Format::dump fn

Cargo.toml

@@ -8,6 +8,8 @@ edition = "2021"
 [dependencies]
 clap = { version = "4", features = ["derive"] }
 
+thiserror = "1"
+
 serde_json = "1.0"
 serde_yaml = "0.9"
 serde = { version = "1.0", features = ["derive"] }

src/errors.rs

@@ -0,0 +1,13 @@
+use thiserror::Error;
+
+#[derive(Error, Debug)]
+pub enum Error {
+    #[error("the data for key `{0}` is not available")]
+    InvalidFormat(String),
+
+    #[error("{0} is not supported yet.")]
+    UnsupportedFormat(String),
+
+    #[error("{0}")]
+    UnknownError(String),
+}

src/main.rs

@@ -11,6 +11,7 @@ use clap::Parser;
 
 mod consts;
 mod cyclone_dx;
+mod errors;
 mod logger;
 mod nix;
 mod sbom;
@@ -93,37 +94,16 @@ fn main() -> Result<std::process::ExitCode, Box<dyn std::error::Error>> {
     log::info!("{} nodes in the package graph", package_graph.len());
 
     log::info!("Creating the SBOM");
-    match output_format {
-        crate::sbom::Format::CycloneDX => {
-            let output = crate::cyclone_dx::dump(&package_graph, &serialization_format);
-            match output {
-                Ok(o) => {
-                    println!("{}", &o);
-                }
-                Err(e) => {
-                    eprintln!("{}", e.to_string());
-                    return Ok(std::process::ExitCode::FAILURE);
-                }
-            };
-        }
-        crate::sbom::Format::SPDX => {
-            eprintln!(
-                "{} is not supported yet.",
-                crate::sbom::Format::SPDX.to_pretty_name()
-            );
+
+    let sbom_dump = match output_format.dump(&serialization_format, &package_graph) {
+        Ok(d) => d,
+        Err(e) => {
+            eprintln!("{}", e.to_string());
             return Ok(std::process::ExitCode::FAILURE);
         }
-        crate::sbom::Format::PrettyPrint => {
-            let display_options = crate::nix::DisplayOptions {
-                print_stdenv: false,
-                print_exclude_list: vec![],
-            };
-            println!(
-                "{}",
-                crate::nix::pretty_print_package_graph(&package_graph, 0, &display_options,)
-            );
-        }
     };
 
+    println!("{}", sbom_dump);
+
     Ok(std::process::ExitCode::SUCCESS)
 }

src/sbom.rs

@@ -38,6 +38,36 @@ impl Format {
             crate::sbom::Format::PrettyPrint => crate::sbom::SerializationFormat::XML,
         }
     }
+
+    pub fn dump(
+        &self,
+        serialization_format: &SerializationFormat,
+        package_graph: &crate::nix::PackageGraph,
+    ) -> Result<String, Box<dyn std::error::Error>> {
+        match self {
+            crate::sbom::Format::CycloneDX => {
+                return match crate::cyclone_dx::dump(&package_graph, &serialization_format) {
+                    Ok(d) => Ok(d),
+                    Err(s) => Err(Box::new(crate::errors::Error::UnknownError(s))),
+                };
+            }
+            crate::sbom::Format::SPDX => Err(Box::new(crate::errors::Error::UnsupportedFormat(
+                "spdx".to_string(),
+            ))),
+            crate::sbom::Format::PrettyPrint => {
+                let display_options = crate::nix::DisplayOptions {
+                    print_stdenv: false,
+                    print_exclude_list: vec![],
+                };
+
+                return Ok(crate::nix::pretty_print_package_graph(
+                    &package_graph,
+                    0,
+                    &display_options,
+                ));
+            }
+        }
+    }
 }
 
 impl Default for Format {