branch: elpa/logview
commit 72b9e05e8456371f1c48632b8cfe4fb00e85812b
Author: Paul Pogonyshev <pogonys...@gmail.com>
Commit: Paul Pogonyshev <pogonys...@gmail.com>
Add a command that refreshes the current buffer by appending if possible,
else reverting it completely.
---
README.md | 1 +
logview.el | 93 +++++++++++++++++++++++++++++++++++++++-----------------------
2 files changed, 60 insertions(+), 34 deletions(-)
diff --git a/README.md b/README.md
index 8233a77f48..498aaef6d3 100644
--- a/README.md
+++ b/README.md
@@ -159,6 +159,7 @@ changed in each individual buffer.
* Customize options that affect submode selection: `o S` or `C-c C-s`
* Bury buffer: `q`
+* Refresh the buffer (appending, if possible) preserving active filters: `g`
* Append log file tail to the buffer: `x`
* Revert the buffer preserving active filters: `X`
* Universal prefix commands are bound without modifiers: `u`, `-`, `0`..`9`
diff --git a/logview.el b/logview.el
index 9579319eb6..1600f4bd36 100644
--- a/logview.el
+++ b/logview.el
@@ -600,6 +600,7 @@ that the line is not the first in the buffer."
("C-c C-s" logview-customize-submode-options)
;; Miscellaneous commands.
("?" logview-mode-help)
+ ("g" logview-refresh-buffer-as-needed)
("x" logview-append-log-file-tail)
("X" logview-revert-buffer)
("q" bury-buffer)
@@ -1265,6 +1266,22 @@ These are:
;; FIXME: Write
)
+(defun logview-refresh-buffer-as-needed ()
+ "Append log file tail or else revert the whole buffer.
+This is conceptually the same as typing
\\<logview-mode-map>\\[logview-append-log-file-tail], followed by
\\<logview-mode-map>\\[logview-revert-buffer] if the
+first command fails.
+
+This command is faster than reloading the whole buffer in the
+common case when the log file grows by appending. Unlike
+`logview-append-log-file-tail', it works in all cases, falling
+back to full revert if the file appears to have changed in a
+different way.
+
+In all cases the current filters are preserved."
+ (interactive)
+ (unless (and (not (buffer-modified-p)) (logview--do-append-log-file-tail t))
+ (logview-revert-buffer)))
+
(defun logview-append-log-file-tail ()
"Load log file tail into the buffer preserving active filters.
This command won't ask for confirmation, but cannot be used if
@@ -1283,40 +1300,7 @@ should be as simple as typing
\\<logview-mode-map>\\[logview-append-log-file-tai
(interactive)
(when (buffer-modified-p)
(user-error "Cannot append file tail to a modified buffer"))
- (let* ((buffer (current-buffer))
- (file buffer-file-name)
- (size (1+ (buffer-size)))
- (reassurance-chars (min (max logview-reassurance-chars 0) (1- size)))
- (compare-from (- size reassurance-chars))
- ;; 'position-bytes' appears to count from 1, yet we need
- ;; zero-based offset.
- (compare-from-bytes (1- (position-bytes compare-from))))
- (with-temp-buffer
- (insert-file-contents file nil compare-from-bytes nil)
- (let ((temporary (current-buffer))
- (temporary-size (buffer-size)))
- (unless (and (>= temporary-size reassurance-chars)
- (string= (buffer-substring-no-properties 1 (1+
reassurance-chars))
- (with-current-buffer buffer
- (save-restriction
- (widen)
- (buffer-substring-no-properties compare-from
size)))))
- (user-error "Buffer contents doesn't match the head of %s anymore"
file))
- (if (= temporary-size reassurance-chars)
- (message "Backing file %s hasn't grown" file)
- (with-current-buffer buffer
- (let ((was-modified (buffer-modified-p))
- (inhibit-read-only t)
- ;; This is to avoid unnecessary confirmation about
- ;; modifying a buffer with externally changed file.
- (buffer-file-name nil))
- (save-restriction
- (widen)
- (save-excursion
- (goto-char (point-max))
- (insert-buffer-substring-no-properties temporary (1+
reassurance-chars) (1+ temporary-size))))
- (restore-buffer-modified-p was-modified))
- (message "Appended the tail of file %s" file)))))))
+ (logview--do-append-log-file-tail))
(defun logview-revert-buffer ()
"Revert the buffer preserving active filters.
@@ -1335,6 +1319,47 @@ as simple as typing
\\<logview-mode-map>\\[logview-revert-buffer], as no confirm
;; If reverting fails we just won't even get here.
(message "Reverted the buffer"))
+(defun logview--do-append-log-file-tail (&optional no-errors)
+ "Perform the work of `logview-append-log-file-tail'.
+If NO-ERRORS is non-nil and the file has changed in a non-growing
+way, returns nil rather than barking. In case of success, always
+returns non-nil."
+ (let* ((buffer (current-buffer))
+ (file buffer-file-name)
+ (size (1+ (buffer-size)))
+ (reassurance-chars (min (max logview-reassurance-chars 0) (1- size)))
+ (compare-from (- size reassurance-chars))
+ ;; 'position-bytes' appears to count from 1, yet we need
+ ;; zero-based offset.
+ (compare-from-bytes (1- (position-bytes compare-from))))
+ (with-temp-buffer
+ (insert-file-contents file nil compare-from-bytes nil)
+ (let ((temporary (current-buffer))
+ (temporary-size (buffer-size)))
+ (if (and (>= temporary-size reassurance-chars)
+ (string= (buffer-substring-no-properties 1 (1+
reassurance-chars))
+ (with-current-buffer buffer
+ (save-restriction
+ (widen)
+ (buffer-substring-no-properties compare-from
size)))))
+ (if (= temporary-size reassurance-chars)
+ (message "Backing file %s hasn't grown" file)
+ (with-current-buffer buffer
+ (let ((was-modified (buffer-modified-p))
+ (inhibit-read-only t)
+ ;; This is to avoid unnecessary confirmation about
+ ;; modifying a buffer with externally changed file.
+ (buffer-file-name nil))
+ (save-restriction
+ (widen)
+ (save-excursion
+ (goto-char (point-max))
+ (insert-buffer-substring-no-properties temporary (1+
reassurance-chars) (1+ temporary-size))))
+ (restore-buffer-modified-p was-modified))
+ (message "Appended the tail of file %s" file)))
+ (unless no-errors
+ (user-error "Buffer contents doesn't match the head of %s anymore"
file)))))))
+
;;; Internal functions (except helpers for specific command groups).
