[PATCH] rust: support arrays in target JSON

[Alice Ryhl <aliceryhl@google.com>]

From: Matthew Maurer <mmaurer@google.com>

Some configuration options such as the supported sanitizer list are
arrays. To support using Rust with sanitizers on x86, we must update the
target.json generator to support this case.

The Push trait is removed in favor of the From trait because the Push
trait doesn't work well in the nested case where you are not really
pushing values to a TargetSpec.

Signed-off-by: Matthew Maurer <mmaurer@google.com>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
---
 scripts/generate_rust_target.rs | 82 +++++++++++++++++++++------------
 1 file changed, 53 insertions(+), 29 deletions(-)

diff --git a/scripts/generate_rust_target.rs b/scripts/generate_rust_target.rs
index 87f34925eb7b..c31657380bf9 100644
--- a/scripts/generate_rust_target.rs
+++ b/scripts/generate_rust_target.rs
@@ -20,12 +20,28 @@ enum Value {
     Boolean(bool),
     Number(i32),
     String(String),
+    Array(Vec<Value>),
     Object(Object),
 }
 
 type Object = Vec<(String, Value)>;
 
+fn comma_sep<T>(
+    seq: &[T],
+    formatter: &mut Formatter<'_>,
+    f: impl Fn(&mut Formatter<'_>, &T) -> Result,
+) -> Result {
+    if let [ref rest @ .., ref last] = seq[..] {
+        for v in rest {
+            f(formatter, v)?;
+            formatter.write_str(",")?;
+        }
+        f(formatter, last)?;
+    }
+    Ok(())
+}
+
-/// Minimal "almost JSON" generator (e.g. no `null`s, no arrays, no escaping),
+/// Minimal "almost JSON" generator (e.g. no `null`s, no escaping),
 /// enough for this purpose.
 impl Display for Value {
     fn fmt(&self, formatter: &mut Formatter<'_>) -> Result {
@@ -33,59 +49,67 @@ fn fmt(&self, formatter: &mut Formatter<'_>) -> Result {
             Value::Boolean(boolean) => write!(formatter, "{}", boolean),
             Value::Number(number) => write!(formatter, "{}", number),
             Value::String(string) => write!(formatter, "\"{}\"", string),
+            Value::Array(values) => {
+                formatter.write_str("[")?;
+                comma_sep(&values[..], formatter, |formatter, v| v.fmt(formatter))?;
+                formatter.write_str("]")
+            }
             Value::Object(object) => {
                 formatter.write_str("{")?;
-                if let [ref rest @ .., ref last] = object[..] {
-                    for (key, value) in rest {
-                        write!(formatter, "\"{}\": {},", key, value)?;
-                    }
-                    write!(formatter, "\"{}\": {}", last.0, last.1)?;
-                }
+                comma_sep(&object[..], formatter, |formatter, v| {
+                    write!(formatter, "\"{}\": {}", v.0, v.1)
+                })?;
                 formatter.write_str("}")
             }
         }
     }
 }
 
+impl From<bool> for Value {
+    fn from(value: bool) -> Self {
+        Self::Boolean(value)
+    }
+}
+
+impl From<i32> for Value {
+    fn from(value: i32) -> Self {
+        Self::Number(value)
+    }
+}
+
+impl From<String> for Value {
+    fn from(value: String) -> Self {
+        Self::String(value)
+    }
+}
+
+impl From<&str> for Value {
+    fn from(value: &str) -> Self {
+        Self::String(value.to_string())
+    }
+}
+
+impl From<Object> for Value {
+    fn from(object: Object) -> Self {
+        Self::Object(object)
+    }
+}
+
+impl<T: Into<Value>, const N: usize> From<[T; N]> for Value {
+    fn from(i: [T; N]) -> Self {
+        Self::Array(i.into_iter().map(|v| v.into()).collect())
+    }
+}
+
 struct TargetSpec(Object);
 
 impl TargetSpec {
     fn new() -> TargetSpec {
         TargetSpec(Vec::new())
     }
+
+    fn push(&mut self, key: &str, value: impl Into<Value>) {
+        self.0.push((key.to_string(), value.into()));
+    }
 }
-
-trait Push<T> {
-    fn push(&mut self, key: &str, value: T);
-}
-
-impl Push<bool> for TargetSpec {
-    fn push(&mut self, key: &str, value: bool) {
-        self.0.push((key.to_string(), Value::Boolean(value)));
-    }
-}
-
-impl Push<i32> for TargetSpec {
-    fn push(&mut self, key: &str, value: i32) {
-        self.0.push((key.to_string(), Value::Number(value)));
-    }
-}
-
-impl Push<String> for TargetSpec {
-    fn push(&mut self, key: &str, value: String) {
-        self.0.push((key.to_string(), Value::String(value)));
-    }
-}
-
-impl Push<&str> for TargetSpec {
-    fn push(&mut self, key: &str, value: &str) {
-        self.push(key, value.to_string());
-    }
-}
-
-impl Push<Object> for TargetSpec {
-    fn push(&mut self, key: &str, value: Object) {
-        self.0.push((key.to_string(), Value::Object(value)));
-    }
-}
 
---
base-commit: 8400291e289ee6b2bf9779ff1c83a291501f017b
change-id: 20240730-target-json-arrays-17c8d1799f9b

Best regards,
-- 
Alice Ryhl <aliceryhl@google.com>