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go/cmd/guru/guru.el
Alan Donovan a69e659f44 cmd/guru: fix mode map, again
Change-Id: Ic1fef2e237205ed392912601324415af625417b0
Reviewed-on: https://go-review.googlesource.com/19749
Reviewed-by: Dominik Honnef <dominik@honnef.co>
Reviewed-by: Alan Donovan <adonovan@google.com>
2016-02-22 20:17:02 +00:00

289 lines
10 KiB
EmacsLisp

;;;
;;; Integration of the Go 'guru' analysis tool into Emacs.
;;;
;;; To install the Go guru, run:
;;; $ go get golang.org/x/tools/cmd/guru
;;;
;;; Load this file into Emacs and set go-guru-scope to your
;;; configuration. Then, find a file of Go source code, enable
;;; go-guru-mode, select an expression of interest, and press `C-c C-o d'
;;; (for "describe") or run one of the other go-guru-xxx commands.
(require 'compile)
(require 'go-mode)
(require 'json)
(require 'simple)
(require 'cl)
(defgroup go-guru nil
"Options specific to the Go guru."
:group 'go)
(defcustom go-guru-command "guru"
"The Go guru command."
:type 'string
:group 'go-guru)
(defcustom go-guru-scope ""
"The scope of the analysis. See `go-guru-set-scope'."
:type 'string
:group 'go-guru)
(defvar go-guru--scope-history
nil
"History of values supplied to `go-guru-set-scope'.")
;; Extend go-mode-map.
(let ((m (define-prefix-command 'go-guru-map)))
(define-key m "d" #'go-guru-describe)
(define-key m "f" #'go-guru-freevars)
(define-key m "i" #'go-guru-implements)
(define-key m "c" #'go-guru-peers) ; c for channel
(define-key m "r" #'go-guru-referrers)
(define-key m "j" #'go-guru-definition) ; j for jump
(define-key m "p" #'go-guru-pointsto)
(define-key m "s" #'go-guru-callstack) ; s for stack
(define-key m "<" #'go-guru-callers)
(define-key m ">" #'go-guru-callees))
(define-key go-mode-map (kbd "C-c C-o") #'go-guru-map)
;; TODO(dominikh): Rethink set-scope some. Setting it to a file is
;; painful because it doesn't use find-file, and variables/~ aren't
;; expanded. Setting it to an import path is somewhat painful because
;; it doesn't make use of go-mode's import path completion. One option
;; would be having two different functions, but then we can't
;; automatically call it when no scope has been set. Also it wouldn't
;; easily allow specifying more than one file/package.
(defun go-guru-set-scope ()
"Set the scope for the Go guru, prompting the user to edit the
previous scope.
The scope specifies a set of arguments, separated by spaces.
It may be:
1) a set of packages whose main functions will be analyzed.
2) a list of *.go filenames; they will treated like as a single
package (see #3).
3) a single package whose main function and/or Test* functions
will be analyzed.
In the common case, this is similar to the argument(s) you would
specify to 'go build'."
(interactive)
(let ((scope (read-from-minibuffer "Go guru scope: "
go-guru-scope
nil
nil
'go-guru--scope-history)))
(if (string-equal "" scope)
(error "You must specify a non-empty scope for the Go guru"))
(setq go-guru-scope scope)))
(defun go-guru--run (mode &optional need-scope)
"Run the Go guru in the specified MODE, passing it the selected
region of the current buffer. If NEED-SCOPE, prompt for a scope
if not already set. Mark up the output using `compilation-node`,
replacing each file name with a small hyperlink, and display the
result."
(with-current-buffer (go-guru--exec mode need-scope)
(go-guru--compilation-markup)))
(defun go-guru--exec (mode &optional need-scope flags)
"Execute the Go guru in the specified MODE, passing it the
selected region of the current buffer. If NEED-SCOPE, prompt for
a scope if not already set. Return the output buffer."
(if (not buffer-file-name)
(error "Cannot use guru on a buffer without a file name"))
(and need-scope
(string-equal "" go-guru-scope)
(go-guru-set-scope))
(let* ((filename (file-truename buffer-file-name))
(posn (if (use-region-p)
(format "%s:#%d,#%d"
filename
(1- (go--position-bytes (region-beginning)))
(1- (go--position-bytes (region-end))))
(format "%s:#%d"
filename
(1- (position-bytes (point))))))
(env-vars (go-root-and-paths))
(goroot-env (concat "GOROOT=" (car env-vars)))
(gopath-env (concat "GOPATH=" (mapconcat #'identity (cdr env-vars) ":")))
(output-buffer (get-buffer-create "*go-guru*")))
(with-current-buffer output-buffer
(setq buffer-read-only nil)
(erase-buffer))
(with-current-buffer (get-buffer-create "*go-guru-input*")
(setq buffer-read-only nil)
(erase-buffer)
(go-guru--insert-modified-files)
(let* ((args (append (list "-modified"
"-scope" go-guru-scope)
flags
(list mode posn))))
;; Log the command to *Messages*, for debugging.
(message "Command: %s:" args)
(message nil) ; clears/shrinks minibuffer
(message "Running guru %s..." mode)
;; Use dynamic binding to modify/restore the environment
(let* ((process-environment (list* goroot-env gopath-env process-environment))
(c-p-args (append (list (point-min)
(point-max)
go-guru-command
nil ; delete
output-buffer
t)
args))
(exitcode (apply #'call-process-region c-p-args)))
;; If the command fails, don't show the output buffer,
;; but use its contents (sans final \n) as an error.
(unless (zerop exitcode)
(with-current-buffer output-buffer
(bury-buffer)
(error "%s" (buffer-substring (point-min) (1- (point-max)))))))))
output-buffer))
(defun go-guru--compilation-markup ()
"Present guru output in the current buffer using `compilation-mode'."
(insert "\n")
(compilation-mode)
(setq compilation-error-screen-columns nil)
;; Hide the file/line info to save space.
;; Replace each with a little widget.
;; compilation-mode + this loop = slooow.
;; TODO(adonovan): have guru give us JSON
;; and we'll do the markup directly.
(let ((buffer-read-only nil)
(p 1))
(while (not (null p))
(let ((np (compilation-next-single-property-change p 'compilation-message)))
(if np
(when (equal (line-number-at-pos p) (line-number-at-pos np))
;; Using a fixed width greatly improves readability, so
;; if the filename is longer than 20, show ".../last/17chars.go".
;; This usually includes the last segment of the package name.
;; Don't show the line or column number.
(let* ((loc (buffer-substring p np)) ; "/home/foo/go/pkg/file.go:1:2-3:4"
(i (search ":" loc)))
(setq loc (cond
((null i) "...")
((>= i 17) (concat "..." (substring loc (- i 17) i)))
(t (substring loc 0 i))))
;; np is (typically) the space following ":"; consume it too.
(put-text-property p np 'display (concat loc ":")))
(goto-char np)
(insert " ")
(incf np))) ; so we don't get stuck (e.g. on a panic stack dump)
(setq p np)))
(message nil))
(let ((w (display-buffer (current-buffer))))
(set-window-point w (point-min))))
(defun go-guru--insert-modified-files ()
"Insert the contents of each modified Go buffer into the
current buffer in the format specified by guru's -modified flag."
(mapc #'(lambda (b)
(and (buffer-modified-p b)
(buffer-file-name b)
(string= (file-name-extension (buffer-file-name b)) "go")
(progn
(insert (format "%s\n%d\n"
(buffer-file-name b)
(go-guru--buffer-size-bytes b)))
(insert-buffer-substring b))))
(buffer-list)))
(defun go-guru--buffer-size-bytes (&optional buffer)
"Return the number of bytes in the current buffer.
If BUFFER, return the number of characters in that buffer instead."
(with-current-buffer (or buffer (current-buffer))
(string-bytes (buffer-substring (point-min)
(point-max)))))
(defun go-guru--goto-pos (posn)
"Find the file containing the position POSN (of the form `file:line:col')
set the point to it, switching the current buffer."
(let ((file-line-pos (split-string posn ":")))
(find-file (car file-line-pos))
(goto-char (point-min))
;; NB: go/token's column offsets are byte- not rune-based.
(forward-line (1- (string-to-number (cadr file-line-pos))))
(forward-char (1- (string-to-number (caddr file-line-pos))))))
(defun go-guru-callees ()
"Show possible callees of the function call at the current point."
(interactive)
(go-guru--run "callees" t))
(defun go-guru-callers ()
"Show the set of callers of the function containing the current point."
(interactive)
(go-guru--run "callers" t))
(defun go-guru-callgraph ()
"Show the callgraph of the current program."
(interactive)
(go-guru--run "callgraph" t))
(defun go-guru-callstack ()
"Show an arbitrary path from a root of the call graph to the
function containing the current point."
(interactive)
(go-guru--run "callstack" t))
(defun go-guru-definition ()
"Jump to the definition of the selected identifier."
(interactive)
;; TODO(adonovan): use -format=sexpr when available to avoid a
;; dependency and to simplify parsing.
(let* ((res (with-current-buffer (go-guru--exec "definition" nil '("-format=json"))
(goto-char (point-min))
(cdr (car (json-read)))))
(desc (cdr (assoc 'desc res))))
(go-guru--goto-pos (cdr (assoc 'objpos res)))
(message "%s" desc)))
(defun go-guru-describe ()
"Describe the selected syntax, its kind, type and methods."
(interactive)
(go-guru--run "describe"))
(defun go-guru-pointsto ()
"Show what the selected expression points to."
(interactive)
(go-guru--run "pointsto" t))
(defun go-guru-implements ()
"Describe the 'implements' relation for types in the package
containing the current point."
(interactive)
(go-guru--run "implements"))
(defun go-guru-freevars ()
"Enumerate the free variables of the current selection."
(interactive)
(go-guru--run "freevars"))
(defun go-guru-peers ()
"Enumerate the set of possible corresponding sends/receives for
this channel receive/send operation."
(interactive)
(go-guru--run "peers" t))
(defun go-guru-referrers ()
"Enumerate all references to the object denoted by the selected
identifier."
(interactive)
(go-guru--run "referrers"))
(defun go-guru-whicherrs ()
"Show globals, constants and types to which the selected
expression (of type 'error') may refer."
(interactive)
(go-guru--run "whicherrs" t))
(provide 'go-guru)