package_info: refactor sources parsing with iterator

src/package_info.rs

@@ -214,20 +214,32 @@ async fn get_components(
     Err("Components not found.".into())
 }
 
-/*
-* Parse a 'Sources.gz' debian package file data, to look for a target package and
-* return the data for that package stanza
-*/
-fn parse_sources(
-    data: &[u8],
-    target_package: &str,
-    target_version: Option<&str>,
-) -> Result<Option<PackageStanza>, Box<dyn Error>> {
-    let mut d = GzDecoder::new(data);
-    let mut s = String::new();
-    d.read_to_string(&mut s)?;
+struct DebianSources {
+    splitted_sources: std::str::Split<'static, &'static str>,
+}
+impl DebianSources {
+    fn new(data: &[u8]) -> Result<DebianSources, Box<dyn Error>> {
+        // Gz-decode 'Sources.gz' file into a string, and split it on stanzas
+        let mut d = GzDecoder::new(data);
+        let mut s = String::new();
+        d.read_to_string(&mut s)?;
 
-    for stanza in s.split("\n\n") {
+        // Convert the string to a static lifetime by leaking it
+        let static_str = Box::leak(s.into_boxed_str());
+        let splitted = static_str.split("\n\n");
+
+        Ok(DebianSources {
+            splitted_sources: splitted,
+        })
+    }
+}
+impl Iterator for DebianSources {
+    type Item = HashMap<String, String>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let stanza = self.splitted_sources.next()?;
+
+        // Parse stanza into a hashmap of strings, the fields
         let mut fields: HashMap<String, String> = HashMap::new();
         let mut current_key = String::new();
 
@@ -248,50 +260,62 @@ fn parse_sources(
             }
         }
 
-        if let Some(pkg) = fields.get("Package")
-            && pkg == target_package
-        {
-            // Check version if requested
-            if let Some(ver) = target_version {
-                if let Some(pkg_ver) = fields.get("Version") {
-                    if pkg_ver != ver {
-                        continue;
-                    }
-                } else {
-                    continue;
-                }
-            }
+        Some(fields)
+    }
+}
 
-            let mut files = Vec::new();
-            if let Some(checksums) = fields.get("Checksums-Sha256") {
-                for line in checksums.lines() {
-                    let parts: Vec<&str> = line.split_whitespace().collect();
-                    if parts.len() >= 3 {
-                        files.push(FileEntry {
-                            sha256: parts[0].to_string(),
-                            size: parts[1].parse().unwrap_or(0),
-                            name: parts[2].to_string(),
-                        });
-                    }
-                }
-            }
+/*
+* Parse a 'Sources.gz' debian package file data, to look for a target package and
+* return the data for that package stanza
+*/
+fn parse_sources(
+    data: &[u8],
+    target_package: &str,
+    target_version: Option<&str>,
+) -> Result<Option<PackageStanza>, Box<dyn Error>> {
+    let mut sources = DebianSources::new(data)?;
 
-            return Ok(Some(PackageStanza {
-                package: pkg.clone(),
-                version: fields.get("Version").cloned().unwrap_or_default(),
-                directory: fields.get("Directory").cloned().unwrap_or_default(),
-                format: fields
-                    .get("Format")
-                    .cloned()
-                    .unwrap_or_else(|| "1.0".to_string()),
-                vcs_git: fields.get("Vcs-Git").cloned(),
-                vcs_browser: fields.get("Vcs-Browser").cloned(),
-                files,
-            }));
+    // Find the right package, with the right version if requested
+    let stanza = sources.find(|s| {
+        let pkg = s.get("Package");
+        pkg.is_some()
+            && pkg.unwrap() == target_package
+            && (target_version.is_none() || s.get("Version").unwrap() == target_version.unwrap())
+    });
+
+    if stanza.is_none() {
+        return Ok(None);
+    }
+    let stanza = stanza.unwrap();
+
+    // Parse package files
+    let mut files = Vec::new();
+    if let Some(checksums) = stanza.get("Checksums-Sha256") {
+        for line in checksums.lines() {
+            let parts: Vec<&str> = line.split_whitespace().collect();
+            if parts.len() >= 3 {
+                files.push(FileEntry {
+                    sha256: parts[0].to_string(),
+                    size: parts[1].parse().unwrap_or(0),
+                    name: parts[2].to_string(),
+                });
+            }
         }
     }
 
-    Ok(None)
+    // Return package stanza
+    Ok(Some(PackageStanza {
+        package: stanza.get("Package").cloned().unwrap(),
+        version: stanza.get("Version").cloned().unwrap_or_default(),
+        directory: stanza.get("Directory").cloned().unwrap_or_default(),
+        format: stanza
+            .get("Format")
+            .cloned()
+            .unwrap_or_else(|| "1.0".to_string()),
+        vcs_git: stanza.get("Vcs-Git").cloned(),
+        vcs_browser: stanza.get("Vcs-Browser").cloned(),
+        files,
+    }))
 }
 
 pub async fn get(