Merge pull request #610 from majutsushi/no-cache

autoload/tagbar.vim

@@ -1182,29 +1182,34 @@ function! s:ProcessFile(fname, ftype) abort
 
     call tagbar#debug#log('typeinfo for file to process: ' . string(typeinfo))
 
-    " Use a temporary files for ctags processing instead of the original one.
-    " This allows using Tagbar for files accessed with netrw, and also doesn't
-    " slow down Tagbar for files that sit on slow network drives.
-    let tempfile = tempname()
-    let ext = fnamemodify(fileinfo.fpath, ':e')
-    if ext !=# ''
-        let tempfile .= '.' . ext
-    endif
+    if g:tagbar_use_cache
+        " Use a temporary files for ctags processing instead of the original one.
+        " This allows using Tagbar for files accessed with netrw, and also doesn't
+        " slow down Tagbar for files that sit on slow network drives.
+        let tempfile = tempname()
+        let ext = fnamemodify(fileinfo.fpath, ':e')
+        if ext !=# ''
+            let tempfile .= '.' . ext
+        endif
 
-    call tagbar#debug#log('Caching file into: ' . tempfile)
-    let templines = getbufline(fileinfo.bufnr, 1, '$')
-    let res = writefile(templines, tempfile)
+        call tagbar#debug#log('Caching file into: ' . tempfile)
+        let templines = getbufline(fileinfo.bufnr, 1, '$')
+        let res = writefile(templines, tempfile)
 
-    if res != 0
-        call tagbar#debug#log('Could not create copy '.tempfile)
-        return
-    endif
-    let fileinfo.mtime = getftime(tempfile)
+        if res != 0
+            call tagbar#debug#log('Could not create copy '.tempfile)
+            return
+        endif
+        let fileinfo.mtime = getftime(tempfile)
 
-    let ctags_output = s:ExecuteCtagsOnFile(tempfile, a:fname, typeinfo)
+        let ctags_output = s:ExecuteCtagsOnFile(tempfile, a:fname, typeinfo)
 
-    if !tagbar#debug#enabled()
-        call delete(tempfile)
+        if !tagbar#debug#enabled()
+            call delete(tempfile)
+        endif
+    else
+        call tagbar#debug#log('File caching disabled')
+        let ctags_output = s:ExecuteCtagsOnFile(a:fname, a:fname, typeinfo)
     endif
 
     if ctags_output == -1
@@ -1362,7 +1367,7 @@ function! s:ExecuteCtagsOnFile(fname, realfname, typeinfo) abort
 
     let ctags_output = s:ExecuteCtags(ctags_cmd)
 
-    if v:shell_error || ctags_output =~? 'Warning: cannot open source file'
+    if v:shell_error || ctags_output =~? 'Warning: cannot open \(source\|input\) file'
         call tagbar#debug#log('Command output:')
         call tagbar#debug#log(ctags_output)
         call tagbar#debug#log('Exit code: ' . v:shell_error)

doc/tagbar.txt

@@ -784,6 +784,24 @@ about the tag is echoed out. Set this option to disable that behavior.
 Example:
 >
         let g:tagbar_silent = 1
+                                                           *g:tagbar_use_cache*
+g:tagbar_use_cache~
+Default: 1
+
+By default the file contents are passed to ctags by writing them to
+a temporary file and invoking ctags on that file. This greatly speeds up tag
+generation in the event of slow file systems such as network shares and
+enables tagbar to run even on netrw virtual files that ctags would otherwise
+not be able to find at all. However it does incure the cost of an extra write
+operation. Additionally not all sysems are able to let programs share access
+to temporary file space (for example Snap packages cannot read from the host
+system's temp file space). This setting can disable the cache mechanism
+entriely forcing the tags to be generated from the existing copy of the file
+on disk rather than the current buffer written to a temporary file.
+
+Example:
+>
+        let g:tagbar_use_cache = 0
 <
 
 ------------------------------------------------------------------------------

plugin/tagbar.vim

@@ -77,6 +77,7 @@ function! s:setup_options() abort
         \ ['width', 40],
         \ ['zoomwidth', 1],
         \ ['silent', 0],
+        \ ['use_cache', 1],
     \ ]
 
     for [opt, val] in options