Add MMV_NAME and MCP_NAME compile-time variablesv1.3.0

Due to the sheer popularity of the "mmv" name it might conflict with
other programs installed on the user's computer.

As such the MMV_NAME and MCP_NAME environmental variables can control
the program's name at compile time, allowing the user to avoid name
conflicts with other programs.

If the variables are not set then they will silently default back to
"mmv" and "mcp" respectively.

Signed-off-by: Luca Matei Pintilie <luca@lucamatei.com>
Co-authored-by: Thomas Voss <mail@thomasvoss.com>

3 files changed, 38 insertions, 7 deletions

diff --git a/Makefile b/Makefile
index c49dd38..131acc5 100644
--- a/Makefile
+++ b/Makefile
@@ -6,13 +6,19 @@ MANDIR  = ${DPREFIX}/share/man
 
 target = target/release/mmv
 
+mmv = $${MMV_NAME:-mmv}
+mcp = $${MCP_NAME:-mcp}
+
 all: ${target}
 ${target}: src/main.rs
 	cargo build --release
 
 install:
 	mkdir -p ${DPREFIX}/bin ${DPREFIX}/share/man/man1
-	cp ${target} ${DPREFIX}/bin/mmv
-	cp ${target} ${DPREFIX}/bin/mcp
-	cp mmv.1 ${MANDIR}/man1
-	ln -srf ${MANDIR}/man1/mmv.1 ${MANDIR}/man1/mcp.1
+	cp ${target} ${DPREFIX}/bin/${mmv}
+	cp mmv.1 ${MANDIR}/man1/${mmv}.1
+	ln -srf ${DPREFIX}/bin/${mmv} ${DPREFIX}/bin/${mcp}
+	ln -srf ${MANDIR}/man1/${mmv}.1 ${MANDIR}/man1/${mcp}.1
+
+clean:
+	rm -rf target
diff --git a/README.md b/README.md
index ce25f4f..2066f2f 100644
--- a/README.md
+++ b/README.md
@@ -18,6 +18,24 @@ $ make
 $ sudo make install
 ```
 
+The following environment variables can also be set at compile-time to modify
+the names of the generated binaries:
+
+- `$MMV_NAME`
+    + The name of the file-moving binary (default is `mmv`).  This is also used
+      to name the backups folder in `$XDG_CACHE_HOME`.
+- `$MCP_NAME`
+    + The name of the file-copying binary (default is `mcp`).
+
+If you are compiling with a custom binary name, you want to make sure that the
+environment variables actually get used when performing a `make install`.  If
+you’re using `sudo`, you want to do this with the `-E` flag.
+
+```
+$ MMV_NAME=mmv-rs MCP_NAME=mcp-rs make
+$ MMV_NAME=mmv-rs MCP_NAME=mcp-rs sudo -E make install
+```
+
 ## Examples and Documentation
 
 To avoid repeating myself everywhere, if you would like to see usage examples
diff --git a/src/main.rs b/src/main.rs
index e8fb883..9885a82 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -19,6 +19,10 @@ use {
 	tempfile::tempdir,
 };
 
+
+const MMV_DEFAULT_NAME: &str = "mmv";
+const MCP_DEFAULT_NAME: &str = "mcp";
+
 struct Flags {
 	pub backup: bool,
 	pub dryrun: bool,
@@ -54,7 +58,8 @@ impl Flags {
 		let argv0 = env::args().next().unwrap();
 		let p = Path::new(&argv0).file_name().unwrap();
 
-		if p == "mcp" {
+		let mcp_name = option_env!("MCP_NAME").unwrap_or(MCP_DEFAULT_NAME);
+		if p == mcp_name {
 			flags.mcp = true;
 			flags.backup = false;
 		}
@@ -85,7 +90,8 @@ fn usage(bad_flags: Option<lexopt::Error>) -> ! {
 	}
 	let argv0 = env::args().next().unwrap();
 	let p = Path::new(&argv0).file_name().unwrap();
-	if p == "mcp" {
+	let mcp_name = option_env!("MCP_NAME").unwrap_or(MCP_DEFAULT_NAME);
+	if p == mcp_name {
 		eprintln!("Usage: {} [-0deiv] command [argument ...]", p.to_str().unwrap());
 	} else {
 		eprintln!("Usage: {} [-0deinv] command [argument ...]", p.to_str().unwrap());
@@ -173,9 +179,10 @@ fn work() -> Result<(), io::Error> {
 		let cache_base = env::var("XDG_CACHE_HOME").unwrap_or_else(|_| {
 			err!("XDG_CACHE_HOME variable must be set");
 		});
+		let mmv_name = option_env!("MMV_NAME").unwrap_or(MMV_DEFAULT_NAME);
 		cache_dir = [
 			Path::new(cache_base.as_str()),
-			Path::new("mmv"),
+			Path::new(mmv_name),
 			Path::new(ts.as_str()),
 		]
 		.iter()