emacs: Factor out synchronous notmuch JSON invocations

[notmuch] / emacs / notmuch-lib.el

diff --git a/emacs/notmuch-lib.el b/emacs/notmuch-lib.el
index 3e8647db78c8710e7d3bb0926e8b52729866b3ac..c3d76d22ab53339adf83cc8b11697023e8b46b7d 100644 (file)
--- a/emacs/notmuch-lib.el
+++ b/emacs/notmuch-lib.el
@@ -168,8 +168,14 @@ user-friendly queries."
 
 (defun notmuch-common-do-stash (text)
   "Common function to stash text in kill ring, and display in minibuffer."
-  (kill-new text)
-  (message "Stashed: %s" text))
+  (if text
+      (progn
+       (kill-new text)
+       (message "Stashed: %s" text))
+    ;; There is nothing to stash so stash an empty string so the user
+    ;; doesn't accidentally paste something else somewhere.
+    (kill-new "")
+    (message "Nothing to stash!")))
 
 ;;
 
@@ -310,6 +316,75 @@ string), a property list of face attributes, or a list of these."
        (put-text-property pos next 'face (cons face cur))
        (setq pos next)))))
 
+(defun notmuch-pop-up-error (msg)
+  "Pop up an error buffer displaying MSG.
+
+This will accumulate error messages in the errors buffer until
+the user dismisses it."
+
+  (let ((buf (get-buffer-create "*Notmuch errors*")))
+    (with-current-buffer buf
+      (view-mode-enter nil #'kill-buffer)
+      (let ((inhibit-read-only t))
+       (goto-char (point-max))
+       (unless (bobp)
+         (insert "\n"))
+       (insert msg)
+       (unless (bolp)
+         (insert "\n"))))
+    (pop-to-buffer buf)))
+
+(defun notmuch-check-exit-status (exit-status command &optional output err-file)
+  "If EXIT-STATUS is non-zero, pop up an error buffer and signal an error.
+
+If EXIT-STATUS is non-zero, pop up a notmuch error buffer
+describing the error and signal an Elisp error.  EXIT-STATUS must
+be a number indicating the exit status code of a process or a
+string describing the signal that terminated the process (such as
+returned by `call-process').  COMMAND must be a list giving the
+command and its arguments.  OUTPUT, if provided, is a string
+giving the output of command.  ERR-FILE, if provided, is the name
+of a file containing the error output of command.  OUTPUT and the
+contents of ERR-FILE will be included in the error message."
+
+  ;; This is implemented as a cond to make it easy to expand.
+  (cond
+   ((eq exit-status 0) t)
+   (t
+    (notmuch-pop-up-error
+     (concat
+      (format "Error invoking notmuch.  %s exited with %s%s.\n"
+             (mapconcat #'identity command " ")
+             ;; Signal strings look like "Terminated", hence the
+             ;; colon.
+             (if (integerp exit-status) "status " "signal: ")
+             exit-status)
+      (when err-file
+       (concat "Error:\n"
+               (with-temp-buffer
+                 (insert-file-contents err-file)
+                 (if (eobp)
+                     "(no error output)\n"
+                   (buffer-string)))))
+      (when (and output (not (equal output "")))
+       (format "Output:\n%s" output))))
+    ;; Mimic `process-lines'
+    (error "%s exited with status %s" (car command) exit-status))))
+
+(defun notmuch-call-notmuch-json (&rest args)
+  "Invoke `notmuch-command' with `args' and return the parsed JSON output.
+
+The returned output will represent objects using property lists
+and arrays as lists."
+
+  (with-temp-buffer
+    (apply #'call-process notmuch-command nil (list t nil) nil args)
+    (goto-char (point-min))
+    (let ((json-object-type 'plist)
+         (json-array-type 'list)
+         (json-false 'nil))
+      (json-read))))
+
 ;; Compatibility functions for versions of emacs before emacs 23.
 ;;
 ;; Both functions here were copied from emacs 23 with the following copyright:
@@ -459,15 +534,19 @@ Entering JSON objects is currently unimplemented."
   (with-current-buffer (notmuch-json-buffer jp)
     ;; Disallow terminators
     (setf (notmuch-json-allow-term jp) nil)
-    (or (notmuch-json-scan-to-value jp)
-       (if (/= (char-after) ?\[)
-           (signal 'json-readtable-error (list "expected '['"))
-         (forward-char)
-         (push ?\] (notmuch-json-term-stack jp))
-         ;; Expect a value or terminator next
-         (setf (notmuch-json-next jp) 'expect-value
-               (notmuch-json-allow-term jp) t)
-         t))))
+    ;; Save "next" so we can restore it if there's a syntax error
+    (let ((saved-next (notmuch-json-next jp)))
+      (or (notmuch-json-scan-to-value jp)
+         (if (/= (char-after) ?\[)
+             (progn
+               (setf (notmuch-json-next jp) saved-next)
+               (signal 'json-readtable-error (list "expected '['")))
+           (forward-char)
+           (push ?\] (notmuch-json-term-stack jp))
+           ;; Expect a value or terminator next
+           (setf (notmuch-json-next jp) 'expect-value
+                 (notmuch-json-allow-term jp) t)
+           t)))))
 
 (defun notmuch-json-read (jp)
   "Parse the value at point in JP's buffer.