Add util module, with functions for handling install-id

Cargo.lock

@@ -69,6 +69,7 @@ dependencies = [
  "signal-hook",
  "signal-hook-mio",
  "termion",
+ "uuid",
 ]
 
 [[package]]
@@ -135,6 +136,17 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "acbf1af155f9b9ef647e42cdc158db4b64a1b61f743629225fde6f3e0be2a7c7"
 
+[[package]]
+name = "getrandom"
+version = "0.2.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "be4136b2a15dd319360be1c07d9933517ccf0be8f16bf62a3bee4f0d618df427"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "wasi",
+]
+
 [[package]]
 name = "heck"
 version = "0.4.1"
@@ -332,6 +344,15 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "711b9620af191e0cdc7468a8d14e709c3dcdb115b36f838e601583af800a370a"
 
+[[package]]
+name = "uuid"
+version = "1.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5e395fcf16a7a3d8127ec99782007af141946b4795001f876d54fb0d55978560"
+dependencies = [
+ "getrandom",
+]
+
 [[package]]
 name = "wasi"
 version = "0.11.0+wasi-snapshot-preview1"

Cargo.toml

@@ -20,3 +20,4 @@ serde_json = "1.0.107"
 clap = { version = "4.4.7", features = ["derive"] }
 signal-hook-mio = { version = "0.2.3", features = ["support-v0_8"] }
 signal-hook = "0.3.17"
+uuid = { version = "1.6.1", features = ["v4"] }

src/util.rs

@@ -0,0 +1,63 @@
+use anyhow::{anyhow, bail, Result};
+use std::{env, fs, io::ErrorKind, path::Path, path::PathBuf};
+use uuid::Uuid;
+
+pub fn get_install_id() -> Result<String> {
+    let default_path = state_home()?.join("install-id");
+    let legacy_path = config_home()?.join("install-id");
+
+    if let Some(install_id) = read_install_id(&default_path)? {
+        Ok(install_id)
+    } else if let Some(install_id) = read_install_id(&legacy_path)? {
+        Ok(install_id)
+    } else {
+        create_install_id(&default_path)
+    }
+}
+
+fn read_install_id(path: &PathBuf) -> Result<Option<String>> {
+    match fs::read_to_string(path) {
+        Ok(s) => Ok(Some(s.trim().to_string())),
+
+        Err(e) => {
+            if e.kind() == ErrorKind::NotFound {
+                Ok(None)
+            } else {
+                bail!(e)
+            }
+        }
+    }
+}
+
+fn create_install_id(path: &PathBuf) -> Result<String> {
+    let id = Uuid::new_v4().to_string();
+
+    if let Some(dir) = path.parent() {
+        fs::create_dir_all(dir)?;
+    }
+
+    fs::write(path, &id)?;
+
+    Ok(id)
+}
+
+fn config_home() -> Result<PathBuf> {
+    env::var("ASCIINEMA_CONFIG_HOME")
+        .map(PathBuf::from)
+        .or(env::var("XDG_CONFIG_HOME").map(|home| Path::new(&home).join("asciinema")))
+        .or(env::var("HOME").map(|home| Path::new(&home).join(".config").join("asciinema")))
+        .map_err(|_| anyhow!("need $HOME or $XDG_CONFIG_HOME or $ASCIINEMA_CONFIG_HOME"))
+}
+
+fn state_home() -> Result<PathBuf> {
+    env::var("ASCIINEMA_STATE_HOME")
+        .map(PathBuf::from)
+        .or(env::var("XDG_STATE_HOME").map(|home| Path::new(&home).join("asciinema")))
+        .or(env::var("HOME").map(|home| {
+            Path::new(&home)
+                .join(".local")
+                .join("state")
+                .join("asciinema")
+        }))
+        .map_err(|_| anyhow!("need $HOME or $XDG_STATE_HOME or $ASCIINEMA_STATE_HOME"))
+}