mu4e: add mu4e-headers-search-pre-hook

Just before executing a search, a hook-function
`mu4e-headers-search-pre-hook` is invoked, which receives the search
expression as its parameter.

NEWS.org

@@ -20,6 +20,9 @@
    - Let `mu4e~read-char-choice' become case-insensitive if there is
      no exact match; small convenience that affects most the
      single-char option reading in mu4e.
+   - Now, just before executing a search, a hook-function
+     `mu4e-headers-search-pre-hook` is invoked, which receives the
+     search expression as its parameter.
              
 ** 0.9.16
 

mu4e/mu4e-headers.el

@@ -160,10 +160,9 @@ query have been received and are displayed."
   :type 'hook
   :group 'mu4e-headers)
 
-(defcustom mu4e-headers-search-bookmark-hook nil
-  "Hook run just we're about to do a bookmarked search. The only
-argument is `expr' which is the bookmarked search we're about to
-execute."
+(defcustom mu4e-headers-search-pre-hook nil
+  "Hook run just before executing a new search operation. This
+function receives the query as its parameter."
   :type 'hook
   :group 'mu4e-headers)
 
@@ -1015,6 +1014,7 @@ the query history stack."
 	     (mu4e-context-label)))))
     
     (switch-to-buffer buf)
+    (run-hook-with-args 'mu4e-headers-search-pre-hook expr)
     (mu4e~proc-find
       expr
       mu4e-headers-show-threads
@@ -1300,7 +1300,6 @@ the search."
   (let ((expr
 	  (or expr
 	    (mu4e-ask-bookmark (if edit "Select bookmark: " "Bookmark: ")))))
-    (run-hook-with-args 'mu4e-headers-search-bookmark-hook expr)
     (mu4e-headers-search expr (when edit "Edit bookmark: ") edit)))
 
 (defun mu4e-headers-search-bookmark-edit ()

mu4e/mu4e.texi

@@ -827,7 +827,10 @@ Jamie Zawinski's mail threading algorithm,
 found during the indexing process, and if there is no current
 user-interaction. If you do not want such automatic updates, set
 @code{mu4e-headers-auto-update} to @code{nil}.
-@item There is a hook-function @code{mu4e-headers-found-hook} available which
+@item Just before executing a search, a hook-function 
+@code{mu4e-headers-search-pre-hook} is invoked, which receives the
+search expression as its parameter.
+@item Also, there is a hook-function @code{mu4e-headers-found-hook} available which
 is invoked just after @t{mu4e} has completed showing the messages in the
 headers-view.
 @end itemize