1 files changed, 136 insertions, 0 deletions

diff --git a/crates/ra_ide_api/src/rename.rs b/crates/ra_ide_api/src/rename.rs
new file mode 100644
index 000000000..9f8a00ae7
--- /dev/null
+++ b/crates/ra_ide_api/src/rename.rs
@@ -0,0 +1,136 @@
+use relative_path::RelativePathBuf;
+
+use hir::{
+    self, ModuleSource, source_binder::module_from_declaration,
+};
+use ra_syntax::{
+    algo::find_node_at_offset,
+    ast,
+    AstNode,
+    SyntaxNode
+};
+
+use crate::{
+    db::RootDatabase,
+    FilePosition,
+    FileSystemEdit,
+    SourceChange,
+    SourceFileEdit,
+};
+use ra_db::{FilesDatabase, SyntaxDatabase};
+use relative_path::RelativePath;
+
+pub(crate) fn rename(
+    db: &RootDatabase,
+    position: FilePosition,
+    new_name: &str,
+) -> Option<SourceChange> {
+    let source_file = db.source_file(position.file_id);
+    let syntax = source_file.syntax();
+
+    if let Some((ast_name, ast_module)) = find_name_and_module_at_offset(syntax, position) {
+        rename_mod(db, ast_name, ast_module, position, new_name)
+    } else {
+        rename_reference(db, position, new_name)
+    }
+}
+
+fn find_name_and_module_at_offset(
+    syntax: &SyntaxNode,
+    position: FilePosition,
+) -> Option<(&ast::Name, &ast::Module)> {
+    let ast_name = find_node_at_offset::<ast::Name>(syntax, position.offset);
+    let ast_name_parent = ast_name
+        .and_then(|n| n.syntax().parent())
+        .and_then(|p| ast::Module::cast(p));
+
+    if let (Some(ast_module), Some(name)) = (ast_name_parent, ast_name) {
+        return Some((name, ast_module));
+    }
+    None
+}
+
+fn rename_mod(
+    db: &RootDatabase,
+    ast_name: &ast::Name,
+    ast_module: &ast::Module,
+    position: FilePosition,
+    new_name: &str,
+) -> Option<SourceChange> {
+    let mut source_file_edits = Vec::new();
+    let mut file_system_edits = Vec::new();
+
+    if let Some(module) = module_from_declaration(db, position.file_id, &ast_module) {
+        let (file_id, module_source) = module.definition_source(db);
+        match module_source {
+            ModuleSource::SourceFile(..) => {
+                let mod_path: RelativePathBuf = db.file_relative_path(file_id);
+                // mod is defined in path/to/dir/mod.rs
+                let dst_path = if mod_path.file_stem() == Some("mod") {
+                    mod_path
+                        .parent()
+                        .and_then(|p| p.parent())
+                        .or_else(|| Some(RelativePath::new("")))
+                        .map(|p| p.join(new_name).join("mod.rs"))
+                } else {
+                    Some(mod_path.with_file_name(new_name).with_extension("rs"))
+                };
+                if let Some(path) = dst_path {
+                    let move_file = FileSystemEdit::MoveFile {
+                        src: file_id,
+                        dst_source_root: db.file_source_root(position.file_id),
+                        dst_path: path,
+                    };
+                    file_system_edits.push(move_file);
+                }
+            }
+            ModuleSource::Module(..) => {}
+        }
+    }
+
+    let edit = SourceFileEdit {
+        file_id: position.file_id,
+        edit: {
+            let mut builder = ra_text_edit::TextEditBuilder::default();
+            builder.replace(ast_name.syntax().range(), new_name.into());
+            builder.finish()
+        },
+    };
+    source_file_edits.push(edit);
+
+    return Some(SourceChange {
+        label: "rename".to_string(),
+        source_file_edits,
+        file_system_edits,
+        cursor_position: None,
+    });
+}
+
+fn rename_reference(
+    db: &RootDatabase,
+    position: FilePosition,
+    new_name: &str,
+) -> Option<SourceChange> {
+    let edit = db
+        .find_all_refs(position)
+        .iter()
+        .map(|(file_id, text_range)| SourceFileEdit {
+            file_id: *file_id,
+            edit: {
+                let mut builder = ra_text_edit::TextEditBuilder::default();
+                builder.replace(*text_range, new_name.into());
+                builder.finish()
+            },
+        })
+        .collect::<Vec<_>>();
+    if edit.is_empty() {
+        return None;
+    }
+
+    return Some(SourceChange {
+        label: "rename".to_string(),
+        source_file_edits: edit,
+        file_system_edits: Vec::new(),
+        cursor_position: None,
+    });
+}