1 files changed, 145 insertions, 0 deletions

diff --git a/crates/ide/src/status.rs b/crates/ide/src/status.rs
new file mode 100644
index 000000000..c23708181
--- /dev/null
+++ b/crates/ide/src/status.rs
@@ -0,0 +1,145 @@
+use std::{fmt, iter::FromIterator, sync::Arc};
+
+use base_db::{
+    salsa::debug::{DebugQueryTable, TableEntry},
+    FileTextQuery, SourceRootId,
+};
+use hir::MacroFile;
+use ide_db::{
+    symbol_index::{LibrarySymbolsQuery, SymbolIndex},
+    RootDatabase,
+};
+use profile::{memory_usage, Bytes};
+use rustc_hash::FxHashMap;
+use syntax::{ast, Parse, SyntaxNode};
+
+use crate::FileId;
+
+fn syntax_tree_stats(db: &RootDatabase) -> SyntaxTreeStats {
+    base_db::ParseQuery.in_db(db).entries::<SyntaxTreeStats>()
+}
+fn macro_syntax_tree_stats(db: &RootDatabase) -> SyntaxTreeStats {
+    hir::db::ParseMacroQuery.in_db(db).entries::<SyntaxTreeStats>()
+}
+
+// Feature: Status
+//
+// Shows internal statistic about memory usage of rust-analyzer.
+//
+// |===
+// | Editor  | Action Name
+//
+// | VS Code | **Rust Analyzer: Status**
+// |===
+pub(crate) fn status(db: &RootDatabase) -> String {
+    let files_stats = FileTextQuery.in_db(db).entries::<FilesStats>();
+    let syntax_tree_stats = syntax_tree_stats(db);
+    let macro_syntax_tree_stats = macro_syntax_tree_stats(db);
+    let symbols_stats = LibrarySymbolsQuery.in_db(db).entries::<LibrarySymbolsStats>();
+    format!(
+        "{}\n{}\n{}\n{} (macros)\n\n\nmemory:\n{}\ngc {:?} seconds ago",
+        files_stats,
+        symbols_stats,
+        syntax_tree_stats,
+        macro_syntax_tree_stats,
+        memory_usage(),
+        db.last_gc.elapsed().as_secs(),
+    )
+}
+
+#[derive(Default)]
+struct FilesStats {
+    total: usize,
+    size: Bytes,
+}
+
+impl fmt::Display for FilesStats {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        write!(fmt, "{} ({}) files", self.total, self.size)
+    }
+}
+
+impl FromIterator<TableEntry<FileId, Arc<String>>> for FilesStats {
+    fn from_iter<T>(iter: T) -> FilesStats
+    where
+        T: IntoIterator<Item = TableEntry<FileId, Arc<String>>>,
+    {
+        let mut res = FilesStats::default();
+        for entry in iter {
+            res.total += 1;
+            res.size += entry.value.unwrap().len();
+        }
+        res
+    }
+}
+
+#[derive(Default)]
+pub(crate) struct SyntaxTreeStats {
+    total: usize,
+    pub(crate) retained: usize,
+}
+
+impl fmt::Display for SyntaxTreeStats {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        write!(fmt, "{} trees, {} retained", self.total, self.retained)
+    }
+}
+
+impl FromIterator<TableEntry<FileId, Parse<ast::SourceFile>>> for SyntaxTreeStats {
+    fn from_iter<T>(iter: T) -> SyntaxTreeStats
+    where
+        T: IntoIterator<Item = TableEntry<FileId, Parse<ast::SourceFile>>>,
+    {
+        let mut res = SyntaxTreeStats::default();
+        for entry in iter {
+            res.total += 1;
+            res.retained += entry.value.is_some() as usize;
+        }
+        res
+    }
+}
+
+impl<M> FromIterator<TableEntry<MacroFile, Option<(Parse<SyntaxNode>, M)>>> for SyntaxTreeStats {
+    fn from_iter<T>(iter: T) -> SyntaxTreeStats
+    where
+        T: IntoIterator<Item = TableEntry<MacroFile, Option<(Parse<SyntaxNode>, M)>>>,
+    {
+        let mut res = SyntaxTreeStats::default();
+        for entry in iter {
+            res.total += 1;
+            res.retained += entry.value.is_some() as usize;
+        }
+        res
+    }
+}
+
+#[derive(Default)]
+struct LibrarySymbolsStats {
+    total: usize,
+    size: Bytes,
+}
+
+impl fmt::Display for LibrarySymbolsStats {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        write!(fmt, "{} ({}) symbols", self.total, self.size)
+    }
+}
+
+impl FromIterator<TableEntry<(), Arc<FxHashMap<SourceRootId, SymbolIndex>>>>
+    for LibrarySymbolsStats
+{
+    fn from_iter<T>(iter: T) -> LibrarySymbolsStats
+    where
+        T: IntoIterator<Item = TableEntry<(), Arc<FxHashMap<SourceRootId, SymbolIndex>>>>,
+    {
+        let mut res = LibrarySymbolsStats::default();
+        for entry in iter {
+            let value = entry.value.unwrap();
+            for symbols in value.values() {
+                res.total += symbols.len();
+                res.size += symbols.memory_size();
+            }
+        }
+        res
+    }
+}