From bac16677e258a560471a920c6fdeac91c3ecb447 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Felici=C3=A1n=20N=C3=A9meth?= <felician.nemeth@gmail.com>
Date: Mon, 28 Feb 2022 14:54:47 +0100
Subject: [PATCH] Add new command: cargo-find-dependency

* cargo.el (cargo-find-dependency): New command.
(cargo-minor-mode-command-map): Bind it to C-S-f.

* cargo-process.el (cargo-process--get-metadata): New defun.

* README.md (Usage): Document the keybinding.
---
 README.md        |  1 +
 cargo-process.el |  9 +++++++++
 cargo.el         | 28 ++++++++++++++++++++++++++++
 3 files changed, 38 insertions(+)

diff --git a/README.md b/README.md
index 52383b9..7b5c340 100644
--- a/README.md
+++ b/README.md
@@ -53,6 +53,7 @@ You will now have the following key combinations at your disposal:
  <kbd>C-c C-c C-S-a</kbd> | cargo-process-audit
  <kbd>C-c C-c C-S-r</kbd> | cargo-process-script
  <kbd>C-c C-c C-w</kbd> | cargo-process-watch
+ <kbd>C-c C-c C-S-f</kbd> | cargo-find-dependency
 
 Before executing the task, Emacs will prompt you to save any modified buffers
 associated with the current Cargo project. Setting `compilation-ask-about-save`
diff --git a/cargo-process.el b/cargo-process.el
index 6b8a2db..c9aa610 100644
--- a/cargo-process.el
+++ b/cargo-process.el
@@ -347,6 +347,15 @@ If FILE-NAME is not a TRAMP file, return it unmodified."
                                    (cdr (assoc 'workspace_root metadata-json)))))
       workspace-root)))
 
+(defun cargo-process--get-metadata ()
+  "Return the metadata of the current package as an alist."
+  (when (cargo-process--project-root)
+    (let ((metadata-text
+           (shell-command-to-string
+            (concat (shell-quote-argument cargo-process--custom-path-to-bin)
+                    " metadata --format-version 1"))))
+      (cargo-json-read-from-string metadata-text))))
+
 (defun manifest-path-argument (name)
   (let ((manifest-filename (cargo-process--tramp-file-local-name (cargo-process--project-root "Cargo.toml"))))
     (when (and manifest-filename
diff --git a/cargo.el b/cargo.el
index 3ccd1e3..14dc1f8 100644
--- a/cargo.el
+++ b/cargo.el
@@ -88,6 +88,7 @@
     (define-key km (kbd "C-S-a") 'cargo-process-audit)
     (define-key km (kbd "C-S-r") 'cargo-process-script)
     (define-key km (kbd "C-w") 'cargo-process-watch)
+    (define-key km (kbd "C-S-f") 'cargo-find-dependency)
     km)
   "Keymap for Cargo mode commands after prefix.")
 (fset 'cargo-minor-mode-command-map cargo-minor-mode-command-map)
@@ -100,6 +101,33 @@
 
 (defvar cargo-minor-mode nil)
 
+(defun cargo-find-dependency (crate &optional metadata)
+  "Find CRATE's Cargo.toml.
+If METADATA is non-nil, use that instead of fetching it with cargo."
+  (interactive (let* ((metadata
+                       (cargo-process--get-metadata))
+                      (crates
+                       (mapcar (lambda (pkg) (alist-get 'name pkg))
+                               (append (alist-get 'packages metadata) nil))))
+                 (list
+                  (completing-read
+                   "Dependency: " crates nil t nil nil (symbol-at-point))
+                  metadata)))
+  (let ((filenames
+         (cl-loop for pkg in (append (alist-get 'packages metadata) nil)
+                  when (equal crate (alist-get 'name pkg))
+                  collect (alist-get 'manifest_path pkg)))
+        ;; Directly `find-file' if there's just a single match.
+        (xref-show-xrefs-function xref-show-definitions-function))
+    (if filenames
+        (xref-show-xrefs (mapcar (lambda (filename)
+                                   (xref-make crate
+                                              (xref-make-file-location
+                                               filename 1 0)))
+                                 filenames)
+                         nil)
+      (message "Can't find: %s" crate))))
+
 ;;;###autoload
 (define-minor-mode cargo-minor-mode
   "Cargo minor mode. Used to hold keybindings for cargo-mode.