2 files changed, 148 insertions, 1 deletions

diff --git a/crates/ra_db/src/fixture.rs b/crates/ra_db/src/fixture.rs
index 469251fe9..f5dd59f84 100644
--- a/crates/ra_db/src/fixture.rs
+++ b/crates/ra_db/src/fixture.rs
@@ -3,9 +3,12 @@
 use std::sync::Arc;
 
 use ra_cfg::CfgOptions;
+use rustc_hash::FxHashMap;
+use test_utils::{extract_offset, parse_fixture, CURSOR_MARKER};
 
 use crate::{
-    CrateGraph, Edition, FileId, RelativePathBuf, SourceDatabaseExt, SourceRoot, SourceRootId,
+    CrateGraph, Edition, FileId, FilePosition, RelativePathBuf, SourceDatabaseExt, SourceRoot,
+    SourceRootId,
 };
 
 pub const WORKSPACE: SourceRootId = SourceRootId(0);
@@ -16,6 +19,19 @@ pub trait WithFixture: Default + SourceDatabaseExt + 'static {
         let file_id = with_single_file(&mut db, text);
         (db, file_id)
     }
+
+    fn with_files(fixture: &str) -> Self {
+        let mut db = Self::default();
+        let pos = with_files(&mut db, fixture);
+        assert!(pos.is_none());
+        db
+    }
+
+    fn with_position(fixture: &str) -> (Self, FilePosition) {
+        let mut db = Self::default();
+        let pos = with_files(&mut db, fixture);
+        (db, pos.unwrap())
+    }
 }
 
 impl<DB: SourceDatabaseExt + Default + 'static> WithFixture for DB {}
@@ -38,3 +54,133 @@ fn with_single_file(db: &mut dyn SourceDatabaseExt, text: &str) -> FileId {
 
     file_id
 }
+
+fn with_files(db: &mut dyn SourceDatabaseExt, fixture: &str) -> Option<FilePosition> {
+    let fixture = parse_fixture(fixture);
+
+    let mut crate_graph = CrateGraph::default();
+    let mut crates = FxHashMap::default();
+    let mut crate_deps = Vec::new();
+    let mut default_crate_root: Option<FileId> = None;
+
+    let mut source_root = SourceRoot::default();
+    let mut source_root_id = WORKSPACE;
+    let mut source_root_prefix: RelativePathBuf = "/".into();
+    let mut file_id = FileId(0);
+
+    let mut file_position = None;
+
+    for entry in fixture.iter() {
+        let meta = match parse_meta(&entry.meta) {
+            ParsedMeta::Root { path } => {
+                let source_root = std::mem::replace(&mut source_root, SourceRoot::default());
+                db.set_source_root(source_root_id, Arc::new(source_root));
+                source_root_id.0 += 1;
+                source_root_prefix = path;
+                continue;
+            }
+            ParsedMeta::File(it) => it,
+        };
+        assert!(meta.path.starts_with(&source_root_prefix));
+
+        if let Some(krate) = meta.krate {
+            let crate_id = crate_graph.add_crate_root(file_id, meta.edition, meta.cfg);
+            let prev = crates.insert(krate.clone(), crate_id);
+            assert!(prev.is_none());
+            for dep in meta.deps {
+                crate_deps.push((krate.clone(), dep))
+            }
+        } else if meta.path == "/main.rs" || meta.path == "/lib.rs" {
+            assert!(default_crate_root.is_none());
+            default_crate_root = Some(file_id);
+        }
+
+        let text = if entry.text.contains(CURSOR_MARKER) {
+            let (offset, text) = extract_offset(&entry.text);
+            assert!(file_position.is_none());
+            file_position = Some(FilePosition { file_id, offset });
+            text.to_string()
+        } else {
+            entry.text.to_string()
+        };
+
+        db.set_file_text(file_id, Arc::new(text));
+        db.set_file_relative_path(file_id, meta.path.clone());
+        db.set_file_source_root(file_id, source_root_id);
+        source_root.insert_file(meta.path, file_id);
+
+        file_id.0 += 1;
+    }
+
+    if crates.is_empty() {
+        let crate_root = default_crate_root.unwrap();
+        crate_graph.add_crate_root(crate_root, Edition::Edition2018, CfgOptions::default());
+    } else {
+        for (from, to) in crate_deps {
+            let from_id = crates[&from];
+            let to_id = crates[&to];
+            crate_graph.add_dep(from_id, to.into(), to_id).unwrap();
+        }
+    }
+
+    db.set_source_root(source_root_id, Arc::new(source_root));
+    db.set_crate_graph(Arc::new(crate_graph));
+
+    file_position
+}
+
+enum ParsedMeta {
+    Root { path: RelativePathBuf },
+    File(FileMeta),
+}
+
+struct FileMeta {
+    path: RelativePathBuf,
+    krate: Option<String>,
+    deps: Vec<String>,
+    cfg: CfgOptions,
+    edition: Edition,
+}
+
+//- /lib.rs crate:foo deps:bar,baz
+fn parse_meta(meta: &str) -> ParsedMeta {
+    let components = meta.split_ascii_whitespace().collect::<Vec<_>>();
+
+    if components[0] == "root" {
+        let path: RelativePathBuf = components[1].into();
+        assert!(path.starts_with("/") && path.ends_with("/"));
+        return ParsedMeta::Root { path };
+    }
+
+    let path: RelativePathBuf = components[0].into();
+    assert!(path.starts_with("/"));
+
+    let mut krate = None;
+    let mut deps = Vec::new();
+    let mut edition = Edition::Edition2018;
+    let mut cfg = CfgOptions::default();
+    for component in components[1..].iter() {
+        let (key, value) = split1(component, ':').unwrap();
+        match key {
+            "crate" => krate = Some(value.to_string()),
+            "deps" => deps = value.split(',').map(|it| it.to_string()).collect(),
+            "edition" => edition = Edition::from_string(&value),
+            "cfg" => {
+                for key in value.split(',') {
+                    match split1(key, '=') {
+                        None => cfg.insert_atom(key.into()),
+                        Some((k, v)) => cfg.insert_key_value(k.into(), v.into()),
+                    }
+                }
+            }
+            _ => panic!("bad component: {:?}", component),
+        }
+    }
+
+    ParsedMeta::File(FileMeta { path, krate, deps, edition, cfg })
+}
+
+fn split1(haystack: &str, delim: char) -> Option<(&str, &str)> {
+    let idx = haystack.find(delim)?;
+    Some((&haystack[..idx], &haystack[idx + delim.len_utf8()..]))
+}
diff --git a/crates/ra_db/src/input.rs b/crates/ra_db/src/input.rs
index eafa95921..7c8dac1d3 100644
--- a/crates/ra_db/src/input.rs
+++ b/crates/ra_db/src/input.rs
@@ -97,6 +97,7 @@ pub enum Edition {
 }
 
 impl Edition {
+    //FIXME: replace with FromStr with proper error handling
     pub fn from_string(s: &str) -> Edition {
         match s {
             "2015" => Edition::Edition2015,