Repository: casey/just
Pull request #1568 (2023-03-23 23:49:51)

Add a num_cpus() function
This is useful for when you are calling `make` from Just and want to pass a `-j` argument


Patch:
diff --git a/Cargo.lock b/Cargo.lock
index 431621ab..87415daf 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -301,6 +301,15 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "hermit-abi"
+version = "0.2.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ee512640fe35acbfb4bb779db6f0d80704c2cacfa2e39b601ef3e3f47d1ae4c7"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "hermit-abi"
 version = "0.3.1"
@@ -370,6 +379,7 @@ dependencies = [
  "lexiclean",
  "libc",
  "log",
+ "num_cpus",
  "pretty_assertions",
  "regex",
  "serde",
@@ -442,6 +452,16 @@ dependencies = [
  "static_assertions",
 ]
 
+[[package]]
+name = "num_cpus"
+version = "1.15.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0fac9e2da13b5eb447a6ce3d392f23a29d8694bff781bf03a16cd9ac8697593b"
+dependencies = [
+ "hermit-abi 0.2.6",
+ "libc",
+]
+
 [[package]]
 name = "once_cell"
 version = "1.17.2"
diff --git a/Cargo.toml b/Cargo.toml
index 065a0ab1..f1b80510 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -31,6 +31,7 @@ heck = "0.4.0"
 lexiclean = "0.0.1"
 libc = "0.2.0"
 log = "0.4.4"
+num_cpus = "1.15.0"
 regex = "1.5.4"
 serde = { version = "1.0.130", features = ["derive", "rc"] }
 serde_json = "1.0.68"
diff --git a/README.md b/README.md
index 3742c3fd..061de68c 100644
--- a/README.md
+++ b/README.md
@@ -1079,6 +1079,7 @@ Done!
 #### System Information
 
 - `arch()` — Instruction set architecture. Possible values are: `"aarch64"`, `"arm"`, `"asmjs"`, `"hexagon"`, `"mips"`, `"msp430"`, `"powerpc"`, `"powerpc64"`, `"s390x"`, `"sparc"`, `"wasm32"`, `"x86"`, `"x86_64"`, and `"xcore"`.
+- `num_cpus()` - Number of logical CPUs.
 - `os()` — Operating system. Possible values are: `"android"`, `"bitrig"`, `"dragonfly"`, `"emscripten"`, `"freebsd"`, `"haiku"`, `"ios"`, `"linux"`, `"macos"`, `"netbsd"`, `"openbsd"`, `"solaris"`, and `"windows"`.
 - `os_family()` — Operating system family; possible values are: `"unix"` and `"windows"`.
 
diff --git a/src/function.rs b/src/function.rs
index 8102c8aa..81481a97 100644
--- a/src/function.rs
+++ b/src/function.rs
@@ -38,6 +38,7 @@ pub(crate) fn get(name: &str) -> Option<Function> {
     "kebabcase" => Unary(kebabcase),
     "lowercamelcase" => Unary(lowercamelcase),
     "lowercase" => Unary(lowercase),
+    "num_cpus" => Nullary(num_cpus),
     "os" => Nullary(os),
     "os_family" => Nullary(os_family),
     "parent_directory" => Unary(parent_directory),
@@ -270,6 +271,11 @@ fn lowercase(_context: &FunctionContext, s: &str) -> Result<String, String> {
   Ok(s.to_lowercase())
 }
 
+fn num_cpus(_context: &FunctionContext) -> Result<String, String> {
+  let num = num_cpus::get();
+  Ok(num.to_string())
+}
+
 fn os(_context: &FunctionContext) -> Result<String, String> {
   Ok(target::os().to_owned())
 }
diff --git a/src/justfile.rs b/src/justfile.rs
index 19199995..a8ae4062 100644
--- a/src/justfile.rs
+++ b/src/justfile.rs
@@ -930,11 +930,11 @@ c := a + b + a + b",
 x := arch()
 
 a:
-  {{os()}} {{os_family()}}",
+  {{os()}} {{os_family()}} {{num_cpus()}}",
     "x := arch()
 
 a:
-    {{ os() }} {{ os_family() }}",
+    {{ os() }} {{ os_family() }} {{ num_cpus() }}",
   }
 
   test! {


Test patch:
diff --git a/tests/functions.rs b/tests/functions.rs
index 4503243c..5511329a 100644
--- a/tests/functions.rs
+++ b/tests/functions.rs
@@ -4,10 +4,10 @@ test! {
   name:     test_os_arch_functions_in_interpolation,
   justfile: r#"
 foo:
-  echo {{arch()}} {{os()}} {{os_family()}}
+  echo {{arch()}} {{os()}} {{os_family()}} {{num_cpus()}}
 "#,
-  stdout:   format!("{} {} {}\n", target::arch(), target::os(), target::family()).as_str(),
-  stderr:   format!("echo {} {} {}\n", target::arch(), target::os(), target::family()).as_str(),
+  stdout:   format!("{} {} {} {}\n", target::arch(), target::os(), target::family(), num_cpus::get()).as_str(),
+  stderr:   format!("echo {} {} {} {}\n", target::arch(), target::os(), target::family(), num_cpus::get()).as_str(),
 }
 
 test! {
@@ -16,12 +16,13 @@ test! {
 a := arch()
 o := os()
 f := os_family()
+n := num_cpus()
 
 foo:
-  echo {{a}} {{o}} {{f}}
+  echo {{a}} {{o}} {{f}} {{n}}
 "#,
-  stdout:   format!("{} {} {}\n", target::arch(), target::os(), target::family()).as_str(),
-  stderr:   format!("echo {} {} {}\n", target::arch(), target::os(), target::family()).as_str(),
+  stdout:   format!("{} {} {} {}\n", target::arch(), target::os(), target::family(), num_cpus::get()).as_str(),
+  stderr:   format!("echo {} {} {} {}\n", target::arch(), target::os(), target::family(), num_cpus::get()).as_str(),
 }
 
 #[cfg(not(windows))]
@@ -246,11 +247,11 @@ test! {
 test! {
   name:     test_os_arch_functions_in_default,
   justfile: r#"
-foo a=arch() o=os() f=os_family():
-  echo {{a}} {{o}} {{f}}
+foo a=arch() o=os() f=os_family() n=num_cpus():
+  echo {{a}} {{o}} {{f}} {{n}}
 "#,
-  stdout:   format!("{} {} {}\n", target::arch(), target::os(), target::family()).as_str(),
-  stderr:   format!("echo {} {} {}\n", target::arch(), target::os(), target::family()).as_str(),
+  stdout:   format!("{} {} {} {}\n", target::arch(), target::os(), target::family(), num_cpus::get()).as_str(),
+  stderr:   format!("echo {} {} {} {}\n", target::arch(), target::os(), target::family(), num_cpus::get()).as_str(),
 }
 
 test! {