Begin transition to new fields for JsonProject crate cfgs

This starts the transition to a new method of documenting the cfgs that are
enabled for a given crate in the json file.  This is changing from a list
of atoms and a dict of key:value pairs, to a list of strings that is
equivalent to that returned by `rustc --print cfg ..`, and parsed in the
same manner by rust-analyzer.

This is the first of two changes, which adds the new field that contains
the list of strings.  Next change will complete the transition and remove
the previous fields.

crates/ra_project_model/src/json_project.rs

@@ -20,8 +20,17 @@ pub struct Crate {
     pub(crate) root_module: PathBuf,
     pub(crate) edition: Edition,
     pub(crate) deps: Vec<Dep>,
+
+    // This is the preferred method of providing cfg options.
+    #[serde(default)]
+    pub(crate) cfg: FxHashSet<String>,
+
+    // These two are here for transition only.
+    #[serde(default)]
     pub(crate) atom_cfgs: FxHashSet<String>,
+    #[serde(default)]
     pub(crate) key_value_cfgs: FxHashMap<String, String>,
+
     pub(crate) out_dir: Option<PathBuf>,
     pub(crate) proc_macro_dylib_path: Option<PathBuf>,
 }
@@ -54,3 +63,73 @@ pub struct JsonProject {
     pub(crate) roots: Vec<Root>,
     pub(crate) crates: Vec<Crate>,
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use serde_json::json;
+
+    #[test]
+    fn test_crate_deserialization() {
+        let raw_json = json!(    {
+            "crate_id": 2,
+            "root_module": "this/is/a/file/path.rs",
+            "deps": [
+              {
+                "crate": 1,
+                "name": "some_dep_crate"
+              },
+            ],
+            "edition": "2015",
+            "cfg": [
+              "atom_1",
+              "atom_2",
+              "feature=feature_1",
+              "feature=feature_2",
+              "other=value",
+            ],
+
+        });
+
+        let krate: Crate = serde_json::from_value(raw_json).unwrap();
+
+        assert!(krate.cfg.contains(&"atom_1".to_string()));
+        assert!(krate.cfg.contains(&"atom_2".to_string()));
+        assert!(krate.cfg.contains(&"feature=feature_1".to_string()));
+        assert!(krate.cfg.contains(&"feature=feature_2".to_string()));
+        assert!(krate.cfg.contains(&"other=value".to_string()));
+    }
+
+    #[test]
+    fn test_crate_deserialization_old_json() {
+        let raw_json = json!(    {
+           "crate_id": 2,
+           "root_module": "this/is/a/file/path.rs",
+           "deps": [
+             {
+               "crate": 1,
+               "name": "some_dep_crate"
+             },
+           ],
+           "edition": "2015",
+           "atom_cfgs": [
+             "atom_1",
+             "atom_2",
+           ],
+           "key_value_cfgs": {
+             "feature": "feature_1",
+             "feature": "feature_2",
+             "other": "value",
+           },
+        });
+
+        let krate: Crate = serde_json::from_value(raw_json).unwrap();
+
+        assert!(krate.atom_cfgs.contains(&"atom_1".to_string()));
+        assert!(krate.atom_cfgs.contains(&"atom_2".to_string()));
+        assert!(krate.key_value_cfgs.contains_key(&"feature".to_string()));
+        assert_eq!(krate.key_value_cfgs.get("feature"), Some(&"feature_2".to_string()));
+        assert!(krate.key_value_cfgs.contains_key(&"other".to_string()));
+        assert_eq!(krate.key_value_cfgs.get("other"), Some(&"value".to_string()));
+    }
+}

crates/ra_project_model/src/lib.rs

@@ -273,6 +273,16 @@ impl ProjectWorkspace {
                         };
                         let cfg_options = {
                             let mut opts = default_cfg_options.clone();
+                            for cfg in &krate.cfg {
+                                match cfg.find('=') {
+                                    None => opts.insert_atom(cfg.into()),
+                                    Some(pos) => {
+                                        let key = &cfg[..pos];
+                                        let value = cfg[pos + 1..].trim_matches('"');
+                                        opts.insert_key_value(key.into(), value.into());
+                                    }
+                                }
+                            }
                             for name in &krate.atom_cfgs {
                                 opts.insert_atom(name.into());
                             }

crates/rust-analyzer/tests/heavy_tests/main.rs

@@ -384,8 +384,9 @@ fn test_missing_module_code_action_in_json_project() {
             "root_module": path.join("src/lib.rs"),
             "deps": [],
             "edition": "2015",
-            "atom_cfgs": [],
-            "key_value_cfgs": {}
+            "cfg": [ "cfg_atom_1", "feature=cfg_1"],
+            "atom_cfgs": ["atom_2"],
+            "key_value_cfgs": { "feature": "key_value_feature", "other": "value"}
         } ]
     });