displaying span information, creation time, and size with polars ls (#12472)

# Description
`polars ls` is already different that `dfr ls`. Currently it just shows
the cache key, columns, rows, and type. I have added:
- creation time
- size
- span contents
-  span start and end

<img width="1471" alt="Screenshot 2024-04-10 at 17 27 06"
src="https://github.com/nushell/nushell/assets/56345/545918b7-7c96-4c25-bc01-b9e2b659a408">

# Tests + Formatting
Done

Co-authored-by: Jack Wright <jack.wright@disqo.com>

crates/nu_plugin_polars/src/cache.rs

@@ -3,19 +3,28 @@ use std::{
     sync::{Mutex, MutexGuard},
 };
 
+use chrono::{DateTime, FixedOffset, Local};
 use nu_plugin::EngineInterface;
-use nu_protocol::{LabeledError, ShellError};
+use nu_protocol::{LabeledError, ShellError, Span};
 use uuid::Uuid;
 
 use crate::{plugin_debug, values::PolarsPluginObject, PolarsPlugin};
 
+#[derive(Debug, Clone)]
+pub struct CacheValue {
+    pub uuid: Uuid,
+    pub value: PolarsPluginObject,
+    pub created: DateTime<FixedOffset>,
+    pub span: Span,
+}
+
 #[derive(Default)]
 pub struct Cache {
-    cache: Mutex<HashMap<Uuid, PolarsPluginObject>>,
+    cache: Mutex<HashMap<Uuid, CacheValue>>,
 }
 
 impl Cache {
-    fn lock(&self) -> Result<MutexGuard<HashMap<Uuid, PolarsPluginObject>>, ShellError> {
+    fn lock(&self) -> Result<MutexGuard<HashMap<Uuid, CacheValue>>, ShellError> {
         self.cache.lock().map_err(|e| ShellError::GenericError {
             error: format!("error acquiring cache lock: {e}"),
             msg: "".into(),
@@ -31,7 +40,7 @@ impl Cache {
         &self,
         maybe_engine: Option<&EngineInterface>,
         uuid: &Uuid,
-    ) -> Result<Option<PolarsPluginObject>, ShellError> {
+    ) -> Result<Option<CacheValue>, ShellError> {
         let mut lock = self.lock()?;
         let removed = lock.remove(uuid);
         plugin_debug!("PolarsPlugin: removing {uuid} from cache: {removed:?}");
@@ -55,7 +64,8 @@ impl Cache {
         maybe_engine: Option<&EngineInterface>,
         uuid: Uuid,
         value: PolarsPluginObject,
-    ) -> Result<Option<PolarsPluginObject>, ShellError> {
+        span: Span,
+    ) -> Result<Option<CacheValue>, ShellError> {
         let mut lock = self.lock()?;
         plugin_debug!("PolarsPlugin: Inserting {uuid} into cache: {value:?}");
         // turn off plugin gc the first time an entry is added to the cache
@@ -68,12 +78,18 @@ impl Cache {
             }
             _ => (),
         };
-        let result = lock.insert(uuid, value);
+        let cache_value = CacheValue {
+            uuid,
+            value,
+            created: Local::now().into(),
+            span,
+        };
+        let result = lock.insert(uuid, cache_value);
         drop(lock);
         Ok(result)
     }
 
-    pub fn get(&self, uuid: &Uuid) -> Result<Option<PolarsPluginObject>, ShellError> {
+    pub fn get(&self, uuid: &Uuid) -> Result<Option<CacheValue>, ShellError> {
         let lock = self.lock()?;
         let result = lock.get(uuid).cloned();
         drop(lock);
@@ -82,12 +98,11 @@ impl Cache {
 
     pub fn process_entries<F, T>(&self, mut func: F) -> Result<Vec<T>, ShellError>
     where
-        F: FnMut((&Uuid, &PolarsPluginObject)) -> Result<T, ShellError>,
+        F: FnMut((&Uuid, &CacheValue)) -> Result<T, ShellError>,
     {
         let lock = self.lock()?;
         let mut vals: Vec<T> = Vec::new();
         for entry in lock.iter() {
-            eprintln!("entry: {:?}", entry);
             let val = func(entry)?;
             vals.push(val);
         }
@@ -103,18 +118,24 @@ pub trait Cacheable: Sized + Clone {
 
     fn from_cache_value(cv: PolarsPluginObject) -> Result<Self, ShellError>;
 
-    fn cache(self, plugin: &PolarsPlugin, engine: &EngineInterface) -> Result<Self, ShellError> {
+    fn cache(
+        self,
+        plugin: &PolarsPlugin,
+        engine: &EngineInterface,
+        span: Span,
+    ) -> Result<Self, ShellError> {
         plugin.cache.insert(
             Some(engine),
             self.cache_id().to_owned(),
             self.to_cache_value()?,
+            span,
         )?;
         Ok(self)
     }
 
     fn get_cached(plugin: &PolarsPlugin, id: &Uuid) -> Result<Option<Self>, ShellError> {
         if let Some(cache_value) = plugin.cache.get(id)? {
-            Ok(Some(Self::from_cache_value(cache_value)?))
+            Ok(Some(Self::from_cache_value(cache_value.value)?))
         } else {
             Ok(None)
         }

crates/nu_plugin_polars/src/dataframe/eager/list.rs

@@ -35,17 +35,25 @@ impl PluginCommand for ListDF {
     fn run(
         &self,
         plugin: &Self::Plugin,
-        _engine: &EngineInterface,
+        engine: &EngineInterface,
         call: &EvaluatedCall,
         _input: PipelineData,
     ) -> Result<PipelineData, LabeledError> {
-        let vals = plugin.cache.process_entries(|(key, value)| match value {
+        let vals = plugin.cache.process_entries(|(key, value)| {
+            let span_contents = engine.get_span_contents(value.span)?;
+            let span_contents = String::from_utf8_lossy(&span_contents);
+            match &value.value {
                 PolarsPluginObject::NuDataFrame(df) => Ok(Some(Value::record(
                     record! {
                         "key" => Value::string(key.to_string(), call.head),
+                        "created" => Value::date(value.created, call.head),
                         "columns" => Value::int(df.as_ref().width() as i64, call.head),
                         "rows" => Value::int(df.as_ref().height() as i64, call.head),
                         "type" => Value::string("NuDataFrame", call.head),
+                        "estimated_size" => Value::filesize(df.to_polars().estimated_size() as i64, call.head),
+                        "span_contents" =>  Value::string(span_contents, value.span),
+                        "span_start" => Value::int(value.span.start as i64, call.head),
+                        "span_end" => Value::int(value.span.end as i64, call.head),
                     },
                     call.head,
                 ))),
@@ -54,9 +62,14 @@ impl PluginCommand for ListDF {
                     Ok(Some(Value::record(
                         record! {
                             "key" => Value::string(key.to_string(), call.head),
+                            "created" => Value::date(value.created, call.head),
                             "columns" => Value::int(lf.as_ref().width() as i64, call.head),
                             "rows" => Value::int(lf.as_ref().height() as i64, call.head),
                             "type" => Value::string("NuLazyFrame", call.head),
+                            "estimated_size" => Value::filesize(lf.to_polars().estimated_size() as i64, call.head),
+                            "span_contents" =>  Value::string(span_contents, value.span),
+                            "span_start" => Value::int(value.span.start as i64, call.head),
+                            "span_end" => Value::int(value.span.end as i64, call.head),
                         },
                         call.head,
                     )))
@@ -64,9 +77,14 @@ impl PluginCommand for ListDF {
                 PolarsPluginObject::NuExpression(_) => Ok(Some(Value::record(
                     record! {
                         "key" => Value::string(key.to_string(), call.head),
+                        "created" => Value::date(value.created, call.head),
                         "columns" => Value::nothing(call.head),
                         "rows" => Value::nothing(call.head),
                         "type" => Value::string("NuExpression", call.head),
+                        "estimated_size" => Value::nothing(call.head),
+                        "span_contents" =>  Value::string(span_contents, value.span),
+                        "span_start" => Value::int(value.span.start as i64, call.head),
+                        "span_end" => Value::int(value.span.end as i64, call.head),
                     },
                     call.head,
                 ))),
@@ -76,6 +94,10 @@ impl PluginCommand for ListDF {
                         "columns" => Value::nothing(call.head),
                         "rows" => Value::nothing(call.head),
                         "type" => Value::string("NuLazyGroupBy", call.head),
+                        "estimated_size" => Value::nothing(call.head),
+                        "span_contents" =>  Value::string(span_contents, call.head),
+                        "span_start" => Value::int(call.head.start as i64, call.head),
+                        "span_end" => Value::int(call.head.end as i64, call.head),
                     },
                     call.head,
                 ))),
@@ -85,9 +107,14 @@ impl PluginCommand for ListDF {
                         "columns" => Value::nothing(call.head),
                         "rows" => Value::nothing(call.head),
                         "type" => Value::string("NuWhen", call.head),
+                        "estimated_size" => Value::nothing(call.head),
+                        "span_contents" =>  Value::string(span_contents.to_string(), call.head),
+                        "span_start" => Value::int(call.head.start as i64, call.head),
+                        "span_end" => Value::int(call.head.end as i64, call.head),
                     },
                     call.head,
                 ))),
+            }
         })?;
         let vals = vals.into_iter().flatten().collect();
         let list = Value::list(vals, call.head);

crates/nu_plugin_polars/src/dataframe/lazy/collect.rs

@@ -66,14 +66,16 @@ impl PluginCommand for LazyCollect {
             PolarsPluginObject::NuLazyFrame(lazy) => {
                 let eager = lazy.collect(call.head)?;
                 Ok(PipelineData::Value(
-                    eager.cache(plugin, engine)?.into_value(call.head),
+                    eager
+                        .cache(plugin, engine, call.head)?
+                        .into_value(call.head),
                     None,
                 ))
             }
             PolarsPluginObject::NuDataFrame(df) => {
                 // just return the dataframe, add to cache again to be safe
                 Ok(PipelineData::Value(
-                    df.cache(plugin, engine)?.into_value(call.head),
+                    df.cache(plugin, engine, call.head)?.into_value(call.head),
                     None,
                 ))
             }

crates/nu_plugin_polars/src/dataframe/lazy/to_lazy.rs

@@ -54,7 +54,7 @@ impl PluginCommand for ToLazyFrame {
         let df = NuDataFrame::try_from_iter(plugin, input.into_iter(), maybe_schema)?;
         let lazy = NuLazyFrame::from_dataframe(df);
         Ok(PipelineData::Value(
-            lazy.cache(plugin, engine)?.into_value(call.head),
+            lazy.cache(plugin, engine, call.head)?.into_value(call.head),
             None,
         ))
     }

crates/nu_plugin_polars/src/dataframe/values/mod.rs

@@ -318,14 +318,14 @@ pub fn cache_and_to_value(
         // if it was from a lazy value, make it lazy again
         PolarsPluginObject::NuDataFrame(df) if df.from_lazy => {
             let df = df.lazy();
-            Ok(df.cache(plugin, engine)?.into_value(span))
+            Ok(df.cache(plugin, engine, span)?.into_value(span))
         }
         // if it was from an eager value, make it eager again
         PolarsPluginObject::NuLazyFrame(lf) if lf.from_eager => {
             let lf = lf.collect(span)?;
-            Ok(lf.cache(plugin, engine)?.into_value(span))
+            Ok(lf.cache(plugin, engine, span)?.into_value(span))
         }
-        _ => Ok(cv.cache(plugin, engine)?.into_value(span)),
+        _ => Ok(cv.cache(plugin, engine, span)?.into_value(span)),
     }
 }
 

crates/nu_plugin_polars/src/dataframe/values/nu_dataframe/custom_value.rs

@@ -81,7 +81,7 @@ impl PolarsPluginCustomValue for NuDataFrameCustomValue {
         let df = NuDataFrame::try_from_custom_value(plugin, self)?;
         Ok(df
             .compute_with_value(plugin, lhs_span, operator.item, operator.span, &right)?
-            .cache(plugin, engine)?
+            .cache(plugin, engine, lhs_span)?
             .into_value(lhs_span))
     }
 
@@ -105,7 +105,9 @@ impl PolarsPluginCustomValue for NuDataFrameCustomValue {
     ) -> Result<Value, ShellError> {
         let df = NuDataFrame::try_from_custom_value(plugin, self)?;
         let column = df.column(&column_name.item, self_span)?;
-        Ok(column.cache(plugin, engine)?.into_value(self_span))
+        Ok(column
+            .cache(plugin, engine, self_span)?
+            .into_value(self_span))
     }
 
     fn custom_value_partial_cmp(

crates/nu_plugin_polars/src/dataframe/values/nu_expression/custom_value.rs

@@ -135,32 +135,32 @@ fn with_operator(
         Operator::Comparison(Comparison::Equal) => Ok(left
             .clone()
             .apply_with_expr(right.clone(), Expr::eq)
-            .cache(plugin, engine)?
+            .cache(plugin, engine, lhs_span)?
             .into_value(lhs_span)),
         Operator::Comparison(Comparison::NotEqual) => Ok(left
             .clone()
             .apply_with_expr(right.clone(), Expr::neq)
-            .cache(plugin, engine)?
+            .cache(plugin, engine, lhs_span)?
             .into_value(lhs_span)),
         Operator::Comparison(Comparison::GreaterThan) => Ok(left
             .clone()
             .apply_with_expr(right.clone(), Expr::gt)
-            .cache(plugin, engine)?
+            .cache(plugin, engine, lhs_span)?
             .into_value(lhs_span)),
         Operator::Comparison(Comparison::GreaterThanOrEqual) => Ok(left
             .clone()
             .apply_with_expr(right.clone(), Expr::gt_eq)
-            .cache(plugin, engine)?
+            .cache(plugin, engine, lhs_span)?
             .into_value(lhs_span)),
         Operator::Comparison(Comparison::LessThan) => Ok(left
             .clone()
             .apply_with_expr(right.clone(), Expr::lt)
-            .cache(plugin, engine)?
+            .cache(plugin, engine, lhs_span)?
             .into_value(lhs_span)),
         Operator::Comparison(Comparison::LessThanOrEqual) => Ok(left
             .clone()
             .apply_with_expr(right.clone(), Expr::lt_eq)
-            .cache(plugin, engine)?
+            .cache(plugin, engine, lhs_span)?
             .into_value(lhs_span)),
         _ => Err(ShellError::OperatorMismatch {
             op_span,
@@ -185,7 +185,7 @@ where
 {
     let expr: NuExpression = f(left.as_ref().clone(), right.as_ref().clone()).into();
 
-    Ok(expr.cache(plugin, engine)?.into_value(span))
+    Ok(expr.cache(plugin, engine, span)?.into_value(span))
 }
 
 impl PolarsPluginCustomValue for NuExpressionCustomValue {

crates/nu_plugin_polars/src/lib.rs

@@ -180,7 +180,7 @@ pub mod test {
     use crate::values::PolarsPluginObject;
     use nu_command::IntoDatetime;
     use nu_plugin_test_support::PluginTest;
-    use nu_protocol::ShellError;
+    use nu_protocol::{ShellError, Span};
 
     pub fn test_polars_plugin_command(command: &impl PluginCommand) -> Result<(), ShellError> {
         let mut plugin = PolarsPlugin::default();
@@ -193,7 +193,10 @@ pub mod test {
                 // if it's a polars plugin object, try to cache it
                 if let Ok(obj) = PolarsPluginObject::try_from_value(&plugin, result) {
                     let id = obj.id();
-                    plugin.cache.insert(None, id, obj).unwrap();
+                    plugin
+                        .cache
+                        .insert(None, id, obj, Span::test_data())
+                        .unwrap();
                 }
             }
         }