[PATCH 0/5] b4: Try to download thread from piem-inboxes URL

[PATCH 0/5] b4: Try to download thread from piem-inboxes URL

[Kyle Meyer]

If a thread can be obtained from the URL returned by piem-inbox-url,
get it from there so that callers don't need to set b4.midmask in
their git configuration.

  [1/5] Use url-http-end-of-headers move to payload
  [2/5] Move "has gunzip?" check to helper
  [3/5] Extract logic from inject-thread-callback
  [4/5] b4: Use a clearer variable name
  [5/5] b4: Try to download thread from piem-inboxes URL

 piem-b4.el | 25 ++++++++++++++++++-------
 piem.el    | 48 +++++++++++++++++++++++++++++++++++++-----------
 2 files changed, 55 insertions(+), 18 deletions(-)


base-commit: ff3b7724a75427c8d73a9b80f9ee5057250479cd
--
2.28.0

[PATCH 1/5] Use url-http-end-of-headers move to payload

[Kyle Meyer]

---
 piem.el | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/piem.el b/piem.el
index 6a3c2b3..bcbec78 100644
--- a/piem.el
+++ b/piem.el
@@ -33,6 +33,8 @@ (require 'rfc2047)
 (require 'subr-x)
 (require 'url)
 
+(defvar url-http-end-of-headers)
+
 \f
 ;;;; Options
 
@@ -397,7 +399,7 @@ (defun piem--inject-thread-callback (status mid message-only)
         (let ((error-status (plist-get status :error)))
           (if error-status
               (signal (car error-status) (cdr error-status))
-            (search-forward "\n\n")
+            (goto-char (1+ url-http-end-of-headers))
             (delete-region (point-min) (point))
             (unless message-only
               (unless (= 0 (call-process-region nil nil "gunzip" nil t))
-- 
2.28.0

[PATCH 2/5] Move "has gunzip?" check to helper

[Kyle Meyer]

This will be needed in another spot.
---
 piem.el | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/piem.el b/piem.el
index bcbec78..4b35938 100644
--- a/piem.el
+++ b/piem.el
@@ -365,6 +365,13 @@ (defun piem-am-ready-mbox ()
 \f
 ;;;; Maildir injection
 
+(defvar piem--has-gunzip)
+(defun piem-check-gunzip ()
+  "Return non-nil if gunzip is available."
+  (unless (boundp 'piem--has-gunzip)
+    (setq piem--has-gunzip (executable-find "gunzip")))
+  piem--has-gunzip)
+
 (defun piem--write-mbox-to-maildir ()
   (let ((n-messages 0))
     (while (and (not (eobp))
@@ -413,8 +420,6 @@ (defun piem--inject-thread-callback (status mid message-only)
       (and (buffer-live-p buffer)
            (kill-buffer buffer)))))
 
-(defvar piem--has-gunzip)
-
 ;;;###autoload
 (defun piem-inject-thread-into-maildir (mid &optional message-only)
   "Inject thread containing MID into `piem-maildir-directory'.
@@ -428,15 +433,13 @@ (defun piem-inject-thread-into-maildir (mid &optional message-only)
    (list (or (piem-mid)
              (user-error "No message ID found for the current buffer"))
          current-prefix-arg))
-  (unless (or message-only (boundp 'piem--has-gunzip))
-    (setq piem--has-gunzip (executable-find "gunzip")))
   (cond
    ((not piem-maildir-directory)
     (user-error "`piem-maildir-directory' is not configured"))
    ((not (piem-maildir-dir-is-maildir-p piem-maildir-directory))
     (user-error
      "`piem-maildir-directory' does not look like a Maildir directory"))
-   ((not (or message-only piem--has-gunzip))
+   ((not (or message-only (piem-check-gunzip)))
     (user-error "gunzip executable not found")))
   (url-retrieve (concat (or (piem-inbox-url)
                             (user-error
-- 
2.28.0

[PATCH 3/5] Extract logic from inject-thread-callback

[Kyle Meyer]

An upcoming commit will use this same logic in another callback.
---
 piem.el | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/piem.el b/piem.el
index 4b35938..94fa1ad 100644
--- a/piem.el
+++ b/piem.el
@@ -372,6 +372,16 @@ (defun piem-check-gunzip ()
     (setq piem--has-gunzip (executable-find "gunzip")))
   piem--has-gunzip)
 
+(defun piem--url-remove-header ()
+  (goto-char (1+ url-http-end-of-headers))
+  (delete-region (point-min) (point)))
+
+(defun piem--url-decompress ()
+  (unless (= 0 (call-process-region nil nil "gunzip" nil t))
+    (error "Decompressing t.mbox.gz failed"))
+  (delete-region (point) (point-max))
+  (goto-char (point-min)))
+
 (defun piem--write-mbox-to-maildir ()
   (let ((n-messages 0))
     (while (and (not (eobp))
@@ -406,13 +416,9 @@ (defun piem--inject-thread-callback (status mid message-only)
         (let ((error-status (plist-get status :error)))
           (if error-status
               (signal (car error-status) (cdr error-status))
-            (goto-char (1+ url-http-end-of-headers))
-            (delete-region (point-min) (point))
+            (piem--url-remove-header)
             (unless message-only
-              (unless (= 0 (call-process-region nil nil "gunzip" nil t))
-                (error "Decompressing t.mbox.gz failed"))
-              (delete-region (point) (point-max)))
-            (goto-char (point-min))
+              (piem--url-decompress))
             (let ((message-count (piem--write-mbox-to-maildir)))
               (message "%d message(s) for %s moved to %s"
                        message-count mid piem-maildir-directory))
-- 
2.28.0

[PATCH 4/5] b4: Use a clearer variable name

[Kyle Meyer]

---
 piem-b4.el | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/piem-b4.el b/piem-b4.el
index 3381b01..537abed 100644
--- a/piem-b4.el
+++ b/piem-b4.el
@@ -56,17 +56,17 @@ (defun piem-b4--get-am-files (mid coderepo args)
                   (make-temp-file "piem-b4-" t)))
          (root (concat outdir "m"))
          (mbox-thread (concat root "-piem"))
-         (custom-p nil))
+         (local-mbox-p nil))
     (when-let ((fn (run-hook-with-args-until-success
                     'piem-mid-to-thread-functions mid)))
       (with-temp-file mbox-thread
         (funcall fn)
         (unless (= (point-max) 1)
-          (setq custom-p t))))
+          (setq local-mbox-p t))))
     ;; Move to the coderepo so that we pick up any b4 configuration
     ;; from there.
     (apply #'piem-process-call coderepo piem-b4-b4-executable "am"
-           (and custom-p
+           (and local-mbox-p
                 (concat "--use-local-mbox=" mbox-thread))
            (concat "--outdir=" outdir)
            (concat "--mbox-name=m")
-- 
2.28.0

[PATCH 5/5] b4: Try to download thread from piem-inboxes URL

[Kyle Meyer]

If a call to piem-b4-am-from-mid fails to generate the thread for a
message ID via piem-mid-to-thread-functions, b4 is called without a
local mbox.  In this case, b4 tries to download the thread from the
URL specified by b4.midmask in the caller's Git configuration.

That works, but it's inconvenient because the user needs to configure
the URL in two places.  If the current buffer is associated with an
inbox in piem-inboxes, try to download the thread from its :url before
falling back to b4's midmask.
---
 piem-b4.el | 19 +++++++++++++++----
 piem.el    | 15 +++++++++++++++
 2 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/piem-b4.el b/piem-b4.el
index 537abed..39d32be 100644
--- a/piem-b4.el
+++ b/piem-b4.el
@@ -47,10 +47,6 @@ (defcustom piem-b4-b4-executable "b4"
 \f
 ;;;; Internals
 
-;; In many cases, we don't really need b4 to download the mbox for us,
-;; as we already have our own mbox to URL mapping.  Perhaps we should
-;; default to using that, but it should still be an option to use b4
-;; so that we honor its customization/URL resolution.
 (defun piem-b4--get-am-files (mid coderepo args)
   (let* ((outdir (file-name-as-directory
                   (make-temp-file "piem-b4-" t)))
@@ -63,6 +59,21 @@ (defun piem-b4--get-am-files (mid coderepo args)
         (funcall fn)
         (unless (= (point-max) 1)
           (setq local-mbox-p t))))
+    ;; `piem-mid-to-thread-functions' didn't generate an mbox.  Next
+    ;; try to download it from a URL at `piem-inboxes'.  Finally, fall
+    ;; back to b4's configuration.
+    (unless local-mbox-p
+      (when-let ((url (piem-inbox-url))
+                 (mid (piem-mid))
+                 (buffer (condition-case nil
+                             (piem-download-and-decompress
+                              (concat url mid "/t.mbox.gz"))
+                           (user-error nil))))
+        (when (buffer-live-p buffer)
+          (with-current-buffer buffer
+            (write-region nil nil mbox-thread))
+          (kill-buffer buffer)
+          (setq local-mbox-p t))))
     ;; Move to the coderepo so that we pick up any b4 configuration
     ;; from there.
     (apply #'piem-process-call coderepo piem-b4-b4-executable "am"
diff --git a/piem.el b/piem.el
index 94fa1ad..0fd1edc 100644
--- a/piem.el
+++ b/piem.el
@@ -382,6 +382,21 @@ (defun piem--url-decompress ()
   (delete-region (point) (point-max))
   (goto-char (point-min)))
 
+(defun piem--decompress-callback (status)
+  (if (plist-get status :error)
+      (kill-buffer (current-buffer))
+    (piem--url-remove-header)
+    (piem--url-decompress)))
+
+(defun piem-download-and-decompress (url)
+  "Retrieve gzipped content at URL and decompress it.
+A buffer with the decompressed content is returned.  A live
+buffer indicates that the request did not result in an error."
+  (unless (piem-check-gunzip)
+    (user-error "gunzip executable not found"))
+  (let ((url-asynchronous nil))
+    (url-retrieve url #'piem--decompress-callback)))
+
 (defun piem--write-mbox-to-maildir ()
   (let ((n-messages 0))
     (while (and (not (eobp))
-- 
2.28.0