feat: resolve package urls when using gf or gF

ftplugin/dart/init.lua

@@ -2,6 +2,7 @@ require("flutter-tools.lsp").attach()
 
 vim.opt_local.comments = [[sO:*\ -,mO:*\ \ ,exO:*/,s1:/*,mb:*,ex:*/,:///,://]]
 vim.opt_local.commentstring = [[//%s]]
+vim.opt.includeexpr = "v:lua.require('flutter-tools.resolve_url').resolve_url(v:fname)"
 
 local function is_nonmodifiable_path()
   local path_parts = { [[.pub-cache]], [[Pub\Cache]], [[/fvm/versions/]] }

lua/flutter-tools/resolve_url.lua

@@ -0,0 +1,111 @@
+-- lua rewrite of the resolve_url function in the Dart plugin
+-- https://github.com/dart-lang/dart-vim-plugin/blob/4bdc04e2540edf90fda2812434c11d19dc04bc8f/autoload/dart.vim#L94
+local M = {}
+
+local function resolve(path)
+  -- Use vim.loop.fs_realpath to resolve symbolic links and get the absolute path
+  local real_path = vim.loop.fs_realpath(path)
+  -- If the path cannot be resolved, return the original
+  return real_path or path
+end
+
+-- Finds a file named `path` in any directory above the open file
+-- Returns a boolean (found or not) and the file path
+local function find_file(path)
+  -- Get the directory path of the current buffer
+  local dir_path = vim.fn.expand("%:p:h")
+
+  -- Search upwards through parent directories
+  while true do
+    local file_path = vim.fs.joinpath(dir_path, path)
+
+    -- If the file is found, return true and the path
+    if vim.fn.filereadable(file_path) == 1 then return true, file_path end
+
+    -- Move to the parent directory
+    local parent = vim.fn.fnamemodify(dir_path, ":h")
+
+    -- If we reach the root directory, break out of the loop
+    if dir_path == parent then break end
+
+    -- Continue searching in the parent directory
+    dir_path = parent
+  end
+
+  -- Return false and an empty string if not found
+  return false, ""
+end
+
+-- A map from package name to lib directory parsed from a 'package_config.json'.
+-- Returns a boolean indicating whether it was found, and the package map.
+local function get_package_map()
+  -- Try to find 'package_config.json' first
+  local found, package_config = find_file(vim.fs.joinpath(".dart_tool", "package_config.json"))
+
+  if found then
+    local dart_tool_dir = vim.fn.fnamemodify(package_config, ":p:h")
+    local content = table.concat(vim.fn.readfile(package_config), "\n")
+    local packages_dict = vim.fn.json_decode(content)
+
+    if packages_dict["configVersion"] ~= 2 then
+      error("Unsupported version of package_config.json")
+      return false, {}
+    end
+
+    local map = {}
+    for _, package in ipairs(packages_dict["packages"]) do
+      local name = package["name"]
+      local uri = package["rootUri"]
+      local package_uri = package["packageUri"] or ""
+      local lib_dir = ""
+
+      -- Resolve file path from uri and packageUri
+      if uri:match("file:/") then
+        uri = uri:gsub("file://", "")
+        lib_dir = resolve(vim.fs.joinpath(uri, package_uri):gsub("/$", ""))
+      else
+        lib_dir = resolve(vim.fs.joinpath(dart_tool_dir, uri, package_uri):gsub("/$", ""))
+      end
+
+      map[name] = lib_dir
+    end
+
+    return true, map
+  end
+
+  -- Return false and an empty map if nothing is found
+  return false, {}
+end
+
+-- Finds the path to `uri`.
+--
+-- Looks for a package_config.json file to resolve the path.
+-- If the path cannot be resolved, or is not a package: uri, returns the original.
+function M.resolve_url(uri)
+  -- Extract package name
+  local package_name = uri:match("([%w_]+)/.*")
+  if not package_name then return uri end
+
+  -- Fetch package map
+  local found, package_map = get_package_map()
+  if not found then
+    error("Cannot find package_config.json file")
+    return uri
+  end
+
+  -- Check if package name is in the package map
+  if not package_map[package_name] then
+    error("No package mapping for " .. package_name)
+    return uri
+  end
+
+  -- Get the path to the package's lib folder
+  local package_lib = package_map[package_name]
+
+  -- Replace the package name part of the URI with the actual package path
+  local resolved_uri = uri:gsub("^" .. package_name, package_lib)
+
+  return resolved_uri
+end
+
+return M