1 files changed, 318 insertions, 0 deletions

diff --git a/crates/ide_db/src/change.rs b/crates/ide_db/src/change.rs
new file mode 100644
index 000000000..8b4fd7ab8
--- /dev/null
+++ b/crates/ide_db/src/change.rs
@@ -0,0 +1,318 @@
+//! Defines a unit of change that can applied to a state of IDE to get the next
+//! state. Changes are transactional.
+
+use std::{fmt, sync::Arc, time};
+
+use base_db::{
+    salsa::{Database, Durability, SweepStrategy},
+    CrateGraph, FileId, SourceDatabase, SourceDatabaseExt, SourceRoot, SourceRootId,
+};
+use profile::{memory_usage, Bytes};
+use rustc_hash::FxHashSet;
+
+use crate::{symbol_index::SymbolsDatabase, RootDatabase};
+
+#[derive(Default)]
+pub struct AnalysisChange {
+    roots: Option<Vec<SourceRoot>>,
+    files_changed: Vec<(FileId, Option<Arc<String>>)>,
+    crate_graph: Option<CrateGraph>,
+}
+
+impl fmt::Debug for AnalysisChange {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        let mut d = fmt.debug_struct("AnalysisChange");
+        if let Some(roots) = &self.roots {
+            d.field("roots", roots);
+        }
+        if !self.files_changed.is_empty() {
+            d.field("files_changed", &self.files_changed.len());
+        }
+        if self.crate_graph.is_some() {
+            d.field("crate_graph", &self.crate_graph);
+        }
+        d.finish()
+    }
+}
+
+impl AnalysisChange {
+    pub fn new() -> AnalysisChange {
+        AnalysisChange::default()
+    }
+
+    pub fn set_roots(&mut self, roots: Vec<SourceRoot>) {
+        self.roots = Some(roots);
+    }
+
+    pub fn change_file(&mut self, file_id: FileId, new_text: Option<Arc<String>>) {
+        self.files_changed.push((file_id, new_text))
+    }
+
+    pub fn set_crate_graph(&mut self, graph: CrateGraph) {
+        self.crate_graph = Some(graph);
+    }
+}
+
+#[derive(Debug)]
+struct AddFile {
+    file_id: FileId,
+    path: String,
+    text: Arc<String>,
+}
+
+#[derive(Debug)]
+struct RemoveFile {
+    file_id: FileId,
+    path: String,
+}
+
+#[derive(Default)]
+struct RootChange {
+    added: Vec<AddFile>,
+    removed: Vec<RemoveFile>,
+}
+
+impl fmt::Debug for RootChange {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+        fmt.debug_struct("AnalysisChange")
+            .field("added", &self.added.len())
+            .field("removed", &self.removed.len())
+            .finish()
+    }
+}
+
+const GC_COOLDOWN: time::Duration = time::Duration::from_millis(100);
+
+impl RootDatabase {
+    pub fn request_cancellation(&mut self) {
+        let _p = profile::span("RootDatabase::request_cancellation");
+        self.salsa_runtime_mut().synthetic_write(Durability::LOW);
+    }
+
+    pub fn apply_change(&mut self, change: AnalysisChange) {
+        let _p = profile::span("RootDatabase::apply_change");
+        self.request_cancellation();
+        log::info!("apply_change {:?}", change);
+        if let Some(roots) = change.roots {
+            let mut local_roots = FxHashSet::default();
+            let mut library_roots = FxHashSet::default();
+            for (idx, root) in roots.into_iter().enumerate() {
+                let root_id = SourceRootId(idx as u32);
+                let durability = durability(&root);
+                if root.is_library {
+                    library_roots.insert(root_id);
+                } else {
+                    local_roots.insert(root_id);
+                }
+                for file_id in root.iter() {
+                    self.set_file_source_root_with_durability(file_id, root_id, durability);
+                }
+                self.set_source_root_with_durability(root_id, Arc::new(root), durability);
+            }
+            self.set_local_roots_with_durability(Arc::new(local_roots), Durability::HIGH);
+            self.set_library_roots_with_durability(Arc::new(library_roots), Durability::HIGH);
+        }
+
+        for (file_id, text) in change.files_changed {
+            let source_root_id = self.file_source_root(file_id);
+            let source_root = self.source_root(source_root_id);
+            let durability = durability(&source_root);
+            // XXX: can't actually remove the file, just reset the text
+            let text = text.unwrap_or_default();
+            self.set_file_text_with_durability(file_id, text, durability)
+        }
+        if let Some(crate_graph) = change.crate_graph {
+            self.set_crate_graph_with_durability(Arc::new(crate_graph), Durability::HIGH)
+        }
+    }
+
+    pub fn maybe_collect_garbage(&mut self) {
+        if cfg!(feature = "wasm") {
+            return;
+        }
+
+        if self.last_gc_check.elapsed() > GC_COOLDOWN {
+            self.last_gc_check = crate::wasm_shims::Instant::now();
+        }
+    }
+
+    pub fn collect_garbage(&mut self) {
+        if cfg!(feature = "wasm") {
+            return;
+        }
+
+        let _p = profile::span("RootDatabase::collect_garbage");
+        self.last_gc = crate::wasm_shims::Instant::now();
+
+        let sweep = SweepStrategy::default().discard_values().sweep_all_revisions();
+
+        base_db::ParseQuery.in_db(self).sweep(sweep);
+        hir::db::ParseMacroQuery.in_db(self).sweep(sweep);
+
+        // Macros do take significant space, but less then the syntax trees
+        // self.query(hir::db::MacroDefQuery).sweep(sweep);
+        // self.query(hir::db::MacroArgTextQuery).sweep(sweep);
+        // self.query(hir::db::MacroExpandQuery).sweep(sweep);
+
+        hir::db::AstIdMapQuery.in_db(self).sweep(sweep);
+
+        hir::db::BodyWithSourceMapQuery.in_db(self).sweep(sweep);
+
+        hir::db::ExprScopesQuery.in_db(self).sweep(sweep);
+        hir::db::InferQueryQuery.in_db(self).sweep(sweep);
+        hir::db::BodyQuery.in_db(self).sweep(sweep);
+    }
+
+    // Feature: Memory Usage
+    //
+    // Clears rust-analyzer's internal database and prints memory usage statistics.
+    //
+    // |===
+    // | Editor  | Action Name
+    //
+    // | VS Code | **Rust Analyzer: Memory Usage (Clears Database)**
+    // |===
+    pub fn per_query_memory_usage(&mut self) -> Vec<(String, Bytes)> {
+        let mut acc: Vec<(String, Bytes)> = vec![];
+        let sweep = SweepStrategy::default().discard_values().sweep_all_revisions();
+        macro_rules! sweep_each_query {
+            ($($q:path)*) => {$(
+                let before = memory_usage().allocated;
+                $q.in_db(self).sweep(sweep);
+                let after = memory_usage().allocated;
+                let q: $q = Default::default();
+                let name = format!("{:?}", q);
+                acc.push((name, before - after));
+
+                let before = memory_usage().allocated;
+                $q.in_db(self).sweep(sweep.discard_everything());
+                let after = memory_usage().allocated;
+                let q: $q = Default::default();
+                let name = format!("{:?} (deps)", q);
+                acc.push((name, before - after));
+
+                let before = memory_usage().allocated;
+                $q.in_db(self).purge();
+                let after = memory_usage().allocated;
+                let q: $q = Default::default();
+                let name = format!("{:?} (purge)", q);
+                acc.push((name, before - after));
+            )*}
+        }
+        sweep_each_query![
+            // SourceDatabase
+            base_db::ParseQuery
+            base_db::CrateGraphQuery
+
+            // SourceDatabaseExt
+            base_db::FileTextQuery
+            base_db::FileSourceRootQuery
+            base_db::SourceRootQuery
+            base_db::SourceRootCratesQuery
+
+            // AstDatabase
+            hir::db::AstIdMapQuery
+            hir::db::MacroArgTextQuery
+            hir::db::MacroDefQuery
+            hir::db::ParseMacroQuery
+            hir::db::MacroExpandQuery
+
+            // DefDatabase
+            hir::db::ItemTreeQuery
+            hir::db::CrateDefMapQueryQuery
+            hir::db::StructDataQuery
+            hir::db::UnionDataQuery
+            hir::db::EnumDataQuery
+            hir::db::ImplDataQuery
+            hir::db::TraitDataQuery
+            hir::db::TypeAliasDataQuery
+            hir::db::FunctionDataQuery
+            hir::db::ConstDataQuery
+            hir::db::StaticDataQuery
+            hir::db::BodyWithSourceMapQuery
+            hir::db::BodyQuery
+            hir::db::ExprScopesQuery
+            hir::db::GenericParamsQuery
+            hir::db::AttrsQuery
+            hir::db::ModuleLangItemsQuery
+            hir::db::CrateLangItemsQuery
+            hir::db::LangItemQuery
+            hir::db::DocumentationQuery
+            hir::db::ImportMapQuery
+
+            // HirDatabase
+            hir::db::InferQueryQuery
+            hir::db::TyQuery
+            hir::db::ValueTyQuery
+            hir::db::ImplSelfTyQuery
+            hir::db::ImplTraitQuery
+            hir::db::FieldTypesQuery
+            hir::db::CallableItemSignatureQuery
+            hir::db::GenericPredicatesForParamQuery
+            hir::db::GenericPredicatesQuery
+            hir::db::GenericDefaultsQuery
+            hir::db::InherentImplsInCrateQuery
+            hir::db::TraitImplsInCrateQuery
+            hir::db::TraitImplsInDepsQuery
+            hir::db::AssociatedTyDataQuery
+            hir::db::AssociatedTyDataQuery
+            hir::db::TraitDatumQuery
+            hir::db::StructDatumQuery
+            hir::db::ImplDatumQuery
+            hir::db::FnDefDatumQuery
+            hir::db::ReturnTypeImplTraitsQuery
+            hir::db::InternCallableDefQuery
+            hir::db::InternTypeParamIdQuery
+            hir::db::InternImplTraitIdQuery
+            hir::db::InternClosureQuery
+            hir::db::AssociatedTyValueQuery
+            hir::db::TraitSolveQuery
+
+            // SymbolsDatabase
+            crate::symbol_index::FileSymbolsQuery
+            crate::symbol_index::LibrarySymbolsQuery
+            crate::symbol_index::LocalRootsQuery
+            crate::symbol_index::LibraryRootsQuery
+
+            // LineIndexDatabase
+            crate::LineIndexQuery
+        ];
+
+        // To collect interned data, we need to bump the revision counter by performing a synthetic
+        // write.
+        // We do this after collecting the non-interned queries to correctly attribute memory used
+        // by interned data.
+        self.salsa_runtime_mut().synthetic_write(Durability::HIGH);
+
+        sweep_each_query![
+            // AstDatabase
+            hir::db::InternMacroQuery
+            hir::db::InternEagerExpansionQuery
+
+            // InternDatabase
+            hir::db::InternFunctionQuery
+            hir::db::InternStructQuery
+            hir::db::InternUnionQuery
+            hir::db::InternEnumQuery
+            hir::db::InternConstQuery
+            hir::db::InternStaticQuery
+            hir::db::InternTraitQuery
+            hir::db::InternTypeAliasQuery
+            hir::db::InternImplQuery
+
+            // HirDatabase
+            hir::db::InternTypeParamIdQuery
+        ];
+
+        acc.sort_by_key(|it| std::cmp::Reverse(it.1));
+        acc
+    }
+}
+
+fn durability(source_root: &SourceRoot) -> Durability {
+    if source_root.is_library {
+        Durability::HIGH
+    } else {
+        Durability::LOW
+    }
+}