Refactor and add new enum PkgFmtDecomposed

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

src/fmt.rs

@@ -0,0 +1,74 @@
+use serde::{Deserialize, Serialize};
+use strum_macros::{Display, EnumString, EnumVariantNames};
+
+/// Binary format enumeration
+#[derive(
+    Debug, Copy, Clone, PartialEq, Serialize, Deserialize, Display, EnumString, EnumVariantNames,
+)]
+#[strum(serialize_all = "snake_case")]
+#[serde(rename_all = "snake_case")]
+pub enum PkgFmt {
+    /// Download format is TAR (uncompressed)
+    Tar,
+    /// Download format is TGZ (TAR + GZip)
+    Tgz,
+    /// Download format is TAR + XZ
+    Txz,
+    /// Download format is TAR + Zstd
+    Tzstd,
+    /// Download format is Zip
+    Zip,
+    /// Download format is raw / binary
+    Bin,
+}
+
+impl Default for PkgFmt {
+    fn default() -> Self {
+        Self::Tgz
+    }
+}
+
+impl PkgFmt {
+    /// If self is one of the tar based formats,
+    /// return Some.
+    pub fn decompose(self) -> PkgFmtDecomposed {
+        match self {
+            PkgFmt::Tar => PkgFmtDecomposed::Tar(TarBasedFmt::Tar),
+            PkgFmt::Tgz => PkgFmtDecomposed::Tar(TarBasedFmt::Tgz),
+            PkgFmt::Txz => PkgFmtDecomposed::Tar(TarBasedFmt::Txz),
+            PkgFmt::Tzstd => PkgFmtDecomposed::Tar(TarBasedFmt::Tzstd),
+            PkgFmt::Bin => PkgFmtDecomposed::Bin,
+            PkgFmt::Zip => PkgFmtDecomposed::Zip,
+        }
+    }
+}
+
+#[derive(Debug, Copy, Clone, PartialEq)]
+pub enum PkgFmtDecomposed {
+    Tar(TarBasedFmt),
+    Bin,
+    Zip,
+}
+
+#[derive(Debug, Copy, Clone, PartialEq)]
+pub enum TarBasedFmt {
+    /// Download format is TAR (uncompressed)
+    Tar,
+    /// Download format is TGZ (TAR + GZip)
+    Tgz,
+    /// Download format is TAR + XZ
+    Txz,
+    /// Download format is TAR + Zstd
+    Tzstd,
+}
+
+impl From<TarBasedFmt> for PkgFmt {
+    fn from(fmt: TarBasedFmt) -> Self {
+        match fmt {
+            TarBasedFmt::Tar => PkgFmt::Tar,
+            TarBasedFmt::Tgz => PkgFmt::Tgz,
+            TarBasedFmt::Txz => PkgFmt::Txz,
+            TarBasedFmt::Tzstd => PkgFmt::Tzstd,
+        }
+    }
+}