BufExplorer/plugin/bufexplorer.vim

"============================================================================
"    Copyright: Copyright (c) 2001-2025, Jeff Lanzarotta
"               All rights reserved.
"
"               Redistribution and use in source and binary forms, with or
"               without modification, are permitted provided that the
"               following conditions are met:
"
"               * Redistributions of source code must retain the above
"                 copyright notice, this list of conditions and the following
"                 disclaimer.
"
"               * Redistributions in binary form must reproduce the above
"                 copyright notice, this list of conditions and the following
"                 disclaimer in the documentation and/or other materials
"                 provided with the distribution.
"
"               * Neither the name of the {organization} nor the names of its
"                 contributors may be used to endorse or promote products
"                 derived from this software without specific prior written
"                 permission.
"
"               THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
"               CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
"               INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
"               MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
"               DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
"               CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
"               SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
"               NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
"               LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
"               HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
"               CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
"               OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
"               EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
" Name Of File: bufexplorer.vim
"  Description: Buffer Explorer Vim Plugin
"   Maintainer: Jeff Lanzarotta (my name at gmail dot com)
" Last Changed: Monday, 17 February 2025
"      Version: See g:bufexplorer_version for version number.
"        Usage: This file should reside in the plugin directory and be
"               automatically sourced.
"
"               You may use the default keymappings of
"
"                 <Leader>be  - Opens BufExplorer
"                 <Leader>bt  - Toggles BufExplorer open or closed
"                 <Leader>bs  - Opens horizontally split window BufExplorer
"                 <Leader>bv  - Opens vertically split window BufExplorer
"
"               Or you can override the defaults and define your own mapping
"               in your vimrc file, for example:
"
"                   nnoremap <silent> <F11> :BufExplorer<CR>
"                   nnoremap <silent> <s-F11> :ToggleBufExplorer<CR>
"                   nnoremap <silent> <m-F11> :BufExplorerHorizontalSplit<CR>
"                   nnoremap <silent> <c-F11> :BufExplorerVerticalSplit<CR>
"
"               Or you can use
"
"                 ":BufExplorer"                - Opens BufExplorer
"                 ":ToggleBufExplorer"          - Opens/Closes BufExplorer
"                 ":BufExplorerHorizontalSplit" - Opens horizontally window BufExplorer
"                 ":BufExplorerVerticalSplit"   - Opens vertically split window BufExplorer
"
"               For more help see supplied documentation.
"      History: See supplied documentation.
"=============================================================================

" Exit quickly if already running or when 'compatible' is set. {{{1
if exists("g:bufexplorer_version") || &cp
    finish
endif
"1}}}

" Version number
let g:bufexplorer_version = "7.6.0"

" Plugin Code {{{1
" Check for Vim version {{{2
if !exists("g:bufExplorerVersionWarn")
    let g:bufExplorerVersionWarn = 1
endif

if v:version < 700
    if g:bufExplorerVersionWarn
        echohl WarningMsg
        echo "Sorry, bufexplorer ".g:bufexplorer_version." required Vim 7.0 or greater."
        echohl None
    endif
    finish
endif

" Check to see if the version of Vim has the correct patch applied, if not, do
" not used <nowait>.
if v:version > 703 || v:version == 703 && has('patch1261') && has('patch1264')
    " We are good to go.
else
    if g:bufExplorerVersionWarn
        echohl WarningMsg
        echo "Sorry, bufexplorer ".g:bufexplorer_version." required Vim 7.3 or greater with patch1261 and patch1264."
        echohl None
    endif
    finish
endif

" Create commands {{{2
command! BufExplorer :call BufExplorer()
command! ToggleBufExplorer :call ToggleBufExplorer()
command! BufExplorerHorizontalSplit :call BufExplorerHorizontalSplit()
command! BufExplorerVerticalSplit :call BufExplorerVerticalSplit()

" Set {{{2
function! s:Set(var, default)
    if !exists(a:var)
        if type(a:default)
            execute "let" a:var "=" string(a:default)
        else
            execute "let" a:var "=" a:default
        endif

        return 1
    endif

    return 0
endfunction

" Script variables {{{2
let s:MRU_Exclude_List = ["[BufExplorer]","__MRU_Files__","[Buf\ List]"]
let s:MRUList = []
let s:name = '[BufExplorer]'
let s:originBuffer = 0
let s:running = 0
let s:sort_by = ["number", "name", "fullpath", "mru", "extension"]
let s:splitMode = ""
let s:didSplit = 0
let s:types = ["fullname", "homename", "path", "relativename", "relativepath", "shortname"]

" Setup the autocommands that handle the MRUList and other stuff. {{{2
autocmd VimEnter * call s:Setup()

" Reset MRUList and buffer->tab associations after loading a session. {{{2
autocmd SessionLoadPost * call s:Reset()

" Setup {{{2
function! s:Setup()
    call s:Reset()

    " Now that the MRUList is created, add the other autocmds.
    augroup BufExplorer
        autocmd!
        autocmd BufEnter,BufNew * call s:ActivateBuffer()
        autocmd BufWipeOut * call s:DeactivateBuffer(1)
        autocmd BufDelete * call s:DeactivateBuffer(0)
        autocmd BufWinEnter \[BufExplorer\] call s:Initialize()
        autocmd BufWinLeave \[BufExplorer\] call s:Cleanup()
    augroup END
endfunction

" Reset {{{2
function! s:Reset()
    " Build initial MRUList. This makes sure all the files specified on the
    " command line are picked up correctly. Check buffers exist so this also
    " works after wiping buffers and loading a session (e.g. sessionman.vim)
    let s:MRUList = filter(range(1, bufnr('$')), 'bufexists(v:val)')

    " Initialize the association of buffers to tabs for any buffers
    " that have been created prior to now, e.g., files specified as
    " vim command line arguments
    call s:CatalogBuffers()
endfunction

" CatalogBuffers {{{2
" Create tab associations for any existing buffers
function! s:CatalogBuffers()
    let ct = tabpagenr()

    for tab in range(1, tabpagenr('$'))
        silent execute 'normal! ' . tab . 'gt'
        for buf in tabpagebuflist()
            call s:UpdateTabBufData(buf)
        endfor
    endfor

    silent execute 'normal! ' . ct . 'gt'
endfunction

" AssociatedTab {{{2
" Return the number of the tab associated with the specified buffer. If the
" buffer is associated with more than one tab, the first one found is
" returned. If the buffer is not associated with any tabs, -1 is returned.
function! s:AssociatedTab(bufnr)
    for tab in range(1, tabpagenr('$'))
        let list = gettabvar(tab, 'bufexp_buf_list', [])
        let idx = index(list, a:bufnr)
        if idx != -1
            return tab
        endif
    endfor

    return -1
endfunction

" RemoveBufFromOtherTabs {{{2
" Remove the specified buffer from the buffer lists of all tabs except the
" current tab.
function! s:RemoveBufFromOtherTabs(bufnr)
    for tab in range(1, tabpagenr('$'))
        if tab == tabpagenr()
            continue
        endif

        let list = gettabvar(tab, 'bufexp_buf_list', [])
        let idx = index(list, a:bufnr)
        if idx == -1
            continue
        endif

        call remove(list, idx)
        call settabvar(tab, 'bufexp_buf_list', list)
    endfor
endfunction

" AddBufToCurrentTab {{{2
" Add the specified buffer to the list of buffers associated with the current
" tab.
function! s:AddBufToCurrentTab(bufnr)
    if index(t:bufexp_buf_list, a:bufnr) == -1
        call add(t:bufexp_buf_list, a:bufnr)
    endif
endfunction

" IsInCurrentTab {{{2
" Returns whether the specified buffer is associated with the current tab.
function! s:IsInCurrentTab(bufnr)
    " It shouldn't happen that the list of buffers is not defined but if it
    " does, play it safe and include the buffer.
    if !exists('t:bufexp_buf_list')
        return 1
    endif

    return (index(t:bufexp_buf_list, a:bufnr) != -1)
endfunction

" UpdateTabBufData {{{2
" Update the tab buffer data for the specified buffer.
"
" The current tab's list is updated. If a buffer is only allowed to be
" associated with one tab, it is removed  from the lists of any other tabs
" with which it may have been associated.
"
" The associations between tabs and buffers are maintained in separate lists
" for each tab, which are stored in tab-specific variables
" 't:bufexp_buf_list'.
function! s:UpdateTabBufData(bufnr)
    " The first time we add a tab, Vim uses the current buffer as its starting
    " page even though we are about to edit a new page, and another BufEnter
    " for the new page is triggered later. Use this first BufEnter to
    " initialize the list of buffers, but don't add the buffer number to the
    " list if it is already associated with another tab.
    "
    " Unfortunately, this doesn't work right when the first buffer opened in
    " the tab should be associated with it, such as when 'tab split +buffer N'
    " is used.
    if !exists("t:bufexp_buf_list")
        let t:bufexp_buf_list = []

        if s:AssociatedTab(a:bufnr) != -1
            return
        endif
    endif

    call s:AddBufToCurrentTab(a:bufnr)

    if g:bufExplorerOnlyOneTab
        call s:RemoveBufFromOtherTabs(a:bufnr)
    endif
endfunction

" ActivateBuffer {{{2
function! s:ActivateBuffer()
    let _bufnr = bufnr("%")
    call s:UpdateTabBufData(_bufnr)
    call s:MRUPush(_bufnr)
endfunction

" DeactivateBuffer {{{2
function! s:DeactivateBuffer(remove)
    let _bufnr = str2nr(expand("<abuf>"))
    call s:MRUPop(_bufnr)
endfunction

" MRUPop {{{2
function! s:MRUPop(bufnr)
    call filter(s:MRUList, 'v:val != '.a:bufnr)
endfunction

" MRUPush {{{2
function! s:MRUPush(buf)
    " Skip temporary buffer with buftype set. Don't add the BufExplorer window
    " to the list.
    if s:ShouldIgnore(a:buf) == 1
        return
    endif

    " Remove the buffer number from the list if it already exists.
    call s:MRUPop(a:buf)

    " Add the buffer number to the head of the list.
    call insert(s:MRUList, a:buf)
endfunction

" ShouldIgnore {{{2
function! s:ShouldIgnore(buf)
    " Ignore temporary buffers with buftype set.
    if empty(getbufvar(a:buf, "&buftype")) == 0
        return 1
    endif

    " Ignore buffers with no name.
    if empty(bufname(a:buf)) == 1
        return 1
    endif

    " Ignore the BufExplorer buffer.
    if fnamemodify(bufname(a:buf), ":t") == s:name
        return 1
    endif

    " Ignore any buffers in the exclude list.
    if index(s:MRU_Exclude_List, bufname(a:buf)) >= 0
        return 1
    endif

    " Else return 0 to indicate that the buffer was not ignored.
    return 0
endfunction

" Initialize {{{2
function! s:Initialize()
    call s:SetLocalSettings()
    let s:running = 1
endfunction

" Cleanup {{{2
function! s:Cleanup()
    if exists("s:_insertmode")
        let &insertmode = s:_insertmode
    endif

    if exists("s:_showcmd")
        let &showcmd = s:_showcmd
    endif

    if exists("s:_cpo")
        let &cpo = s:_cpo
    endif

    if exists("s:_report")
        let &report = s:_report
    endif

    let s:running = 0
    let s:splitMode = ""
    let s:didSplit = 0

    delmarks!
endfunction

" SetLocalSettings {{{2
function! s:SetLocalSettings()
    let s:_insertmode = &insertmode
    set noinsertmode

    let s:_showcmd = &showcmd
    set noshowcmd

    let s:_cpo = &cpo
    set cpo&vim

    let s:_report = &report
    let &report = 10000

    setlocal nonumber
    setlocal foldcolumn=0
    setlocal nofoldenable
    setlocal cursorline
    setlocal nospell
    setlocal nobuflisted
    setlocal filetype=bufexplorer
endfunction

" BufExplorerHorizontalSplit {{{2
function! BufExplorerHorizontalSplit()
    let s:splitMode = "sp"
    execute "BufExplorer"
    let s:splitMode = ""
endfunction

" BufExplorerVerticalSplit {{{2
function! BufExplorerVerticalSplit()
    let s:splitMode = "vsp"
    execute "BufExplorer"
    let s:splitMode = ""
endfunction

" ToggleBufExplorer {{{2
function! ToggleBufExplorer()
    if exists("s:running") && s:running == 1 && bufname(winbufnr(0)) == s:name
        call s:Close()
    else
        call BufExplorer()
    endif
endfunction

" BufExplorer {{{2
function! BufExplorer()
    let name = s:name

    if !has("win32")
        " On non-Windows boxes, escape the name so that is shows up correctly.
        let name = escape(name, "[]")
    endif

    " Make sure there is only one explorer open at a time.
    if s:running == 1
        " Go to the open buffer.
        if has("gui")
            execute "drop" name
        endif

        return
    endif

    " Add zero to ensure the variable is treated as a number.
    let s:originBuffer = bufnr("%") + 0

    silent let s:raw_buffer_listing = s:GetBufferInfo(0)

    " We may have to split the current window.
    if s:splitMode != ""
        " Save off the original settings.
        let [_splitbelow, _splitright] = [&splitbelow, &splitright]

        " Set the setting to ours.
        let [&splitbelow, &splitright] = [g:bufExplorerSplitBelow, g:bufExplorerSplitRight]
        let _size = (s:splitMode == "sp") ? g:bufExplorerSplitHorzSize : g:bufExplorerSplitVertSize

        " Split the window either horizontally or vertically.
        if _size <= 0
            execute 'keepalt ' . s:splitMode
        else
            execute 'keepalt ' . _size . s:splitMode
        endif

        " Restore the original settings.
        let [&splitbelow, &splitright] = [_splitbelow, _splitright]

        " Remember that a split was triggered
        let s:didSplit = 1
    endif

    if !exists("b:displayMode") || b:displayMode != "winmanager"
        " Do not use keepalt when opening bufexplorer to allow the buffer that
        " we are leaving to become the new alternate buffer
        execute "silent keepjumps hide edit".name
    endif

    call s:DisplayBufferList()

    " Position the cursor in the newly displayed list on the line representing
    " the active buffer.  The active buffer is the line with the '%' character
    " in it.
    execute search("%")
endfunction

" DisplayBufferList {{{2
function! s:DisplayBufferList()
    setlocal buftype=nofile
    setlocal modifiable
    setlocal noreadonly
    setlocal noswapfile
    setlocal nowrap
    setlocal bufhidden=wipe

    call s:SetupSyntax()
    call s:MapKeys()

    " Wipe out any existing lines in case BufExplorer buffer exists and the
    " user had changed any global settings that might reduce the number of
    " lines needed in the buffer.
    silent keepjumps 1,$d _

    call setline(1, s:CreateHelp())
    call s:BuildBufferList()
    call cursor(s:firstBufferLine, 1)

    if !g:bufExplorerResize
        normal! zz
    endif

    setlocal nomodifiable
endfunction

" MapKeys {{{2
function! s:MapKeys()
    if exists("b:displayMode") && b:displayMode == "winmanager"
        nnoremap <buffer> <silent> <tab> :call <SID>SelectBuffer()<CR>
    endif

    nnoremap <script> <silent> <nowait> <buffer> <2-leftmouse> :call <SID>SelectBuffer()<CR>
    nnoremap <script> <silent> <nowait> <buffer> <CR>          :call <SID>SelectBuffer()<CR>
    nnoremap <script> <silent> <nowait> <buffer> <F1>          :call <SID>ToggleHelp()<CR>
    nnoremap <script> <silent> <nowait> <buffer> <s-cr>        :call <SID>SelectBuffer("tab")<CR>
    nnoremap <script> <silent> <nowait> <buffer> a             :call <SID>ToggleFindActive()<CR>
    nnoremap <script> <silent> <nowait> <buffer> b             :call <SID>SelectBuffer("ask")<CR>
    nnoremap <script> <silent> <nowait> <buffer> d             :call <SID>RemoveBuffer("delete")<CR>
    xnoremap <script> <silent> <nowait> <buffer> d             :call <SID>RemoveBuffer("delete")<CR>
    nnoremap <script> <silent> <nowait> <buffer> D             :call <SID>RemoveBuffer("wipe")<CR>
    xnoremap <script> <silent> <nowait> <buffer> D             :call <SID>RemoveBuffer("wipe")<CR>
    nnoremap <script> <silent> <nowait> <buffer> f             :call <SID>SelectBuffer("split", "sb")<CR>
    nnoremap <script> <silent> <nowait> <buffer> F             :call <SID>SelectBuffer("split", "st")<CR>
    nnoremap <script> <silent> <nowait> <buffer> m             :call <SID>MRUListShow()<CR>
    nnoremap <script> <silent> <nowait> <buffer> o             :call <SID>SelectBuffer()<CR>
    nnoremap <script> <silent> <nowait> <buffer> p             :call <SID>ToggleSplitOutPathName()<CR>
    nnoremap <script> <silent> <nowait> <buffer> q             :call <SID>Close()<CR>
    nnoremap <script> <silent> <nowait> <buffer> r             :call <SID>SortReverse()<CR>
    nnoremap <script> <silent> <nowait> <buffer> R             :call <SID>ToggleShowRelativePath()<CR>
    nnoremap <script> <silent> <nowait> <buffer> s             :call <SID>SortSelect()<CR>
    nnoremap <script> <silent> <nowait> <buffer> S             :call <SID>ReverseSortSelect()<CR>
    nnoremap <script> <silent> <nowait> <buffer> t             :call <SID>SelectBuffer("tab")<CR>
    nnoremap <script> <silent> <nowait> <buffer> T             :call <SID>ToggleShowTabBuffer()<CR>
    nnoremap <script> <silent> <nowait> <buffer> u             :call <SID>ToggleShowUnlisted()<CR>
    nnoremap <script> <silent> <nowait> <buffer> v             :call <SID>SelectBuffer("split", "vr")<CR>
    nnoremap <script> <silent> <nowait> <buffer> V             :call <SID>SelectBuffer("split", "vl")<CR>
    nnoremap <script> <silent> <nowait> <buffer> H             :call <SID>ToggleShowTerminal()<CR>


    for k in ["G", "n", "N", "L", "M", "H"]
        execute "nnoremap <buffer> <silent>" k ":keepjumps normal!" k."<CR>"
    endfor
endfunction

" SetupSyntax {{{2
function! s:SetupSyntax()
    if has("syntax")
        syn match bufExplorerHelp     "^\".*" contains=bufExplorerSortBy,bufExplorerMapping,bufExplorerTitle,bufExplorerSortType,bufExplorerToggleSplit,bufExplorerToggleOpen
        syn match bufExplorerOpenIn   "Open in \w\+ window" contained
        syn match bufExplorerSplit    "\w\+ split" contained
        syn match bufExplorerSortBy   "Sorted by .*" contained contains=bufExplorerOpenIn,bufExplorerSplit
        syn match bufExplorerMapping  "\" \zs.\+\ze :" contained
        syn match bufExplorerTitle    "Buffer Explorer.*" contained
        syn match bufExplorerSortType "'\w\{-}'" contained
        syn match bufExplorerBufNbr   /^\s*\d\+/
        syn match bufExplorerToggleSplit  "toggle split type" contained
        syn match bufExplorerToggleOpen   "toggle open mode" contained

        syn match bufExplorerModBuf    /^\s*\d\+.\{4}+.*/
        syn match bufExplorerLockedBuf /^\s*\d\+.\{3}[\-=].*/
        syn match bufExplorerHidBuf    /^\s*\d\+.\{2}h.*/
        syn match bufExplorerActBuf    /^\s*\d\+.\{2}a.*/
        syn match bufExplorerCurBuf    /^\s*\d\+.%.*/
        syn match bufExplorerAltBuf    /^\s*\d\+.#.*/
        syn match bufExplorerUnlBuf    /^\s*\d\+u.*/
        syn match bufExplorerInactBuf  /^\s*\d\+ \{7}.*/

        hi def link bufExplorerBufNbr Number
        hi def link bufExplorerMapping NonText
        hi def link bufExplorerHelp Special
        hi def link bufExplorerOpenIn Identifier
        hi def link bufExplorerSortBy String
        hi def link bufExplorerSplit NonText
        hi def link bufExplorerTitle NonText
        hi def link bufExplorerSortType bufExplorerSortBy
        hi def link bufExplorerToggleSplit bufExplorerSplit
        hi def link bufExplorerToggleOpen bufExplorerOpenIn

        hi def link bufExplorerActBuf Identifier
        hi def link bufExplorerAltBuf String
        hi def link bufExplorerCurBuf Type
        hi def link bufExplorerHidBuf Constant
        hi def link bufExplorerLockedBuf Special
        hi def link bufExplorerModBuf Exception
        hi def link bufExplorerUnlBuf Comment
        hi def link bufExplorerInactBuf Comment
    endif
endfunction

" ToggleHelp {{{2
function! s:ToggleHelp()
    let g:bufExplorerDetailedHelp = !g:bufExplorerDetailedHelp

    setlocal modifiable

    " Save position.
    normal! ma

    " Remove old header.
    if s:firstBufferLine > 1
        execute "keepjumps 1,".(s:firstBufferLine - 1) "d _"
    endif

    call append(0, s:CreateHelp())

    silent! normal! g`a
    delmarks a

    setlocal nomodifiable

    if exists("b:displayMode") && b:displayMode == "winmanager"
        call WinManagerForceReSize("BufExplorer")
    endif
endfunction

" GetHelpStatus {{{2
function! s:GetHelpStatus()
    let ret = '" Sorted by '.((g:bufExplorerReverseSort == 1) ? "reverse " : "").g:bufExplorerSortBy
    let ret .= ' | '.((g:bufExplorerFindActive == 0) ? "Don't " : "")."Locate buffer"
    let ret .= ((g:bufExplorerShowUnlisted == 0) ? "" : " | Show unlisted")
    let ret .= ((g:bufExplorerShowTabBuffer == 0) ? "" : " | Show buffers/tab")
    let ret .= ((g:bufExplorerOnlyOneTab == 0) ? "" : " | One tab/buffer")
    let ret .= ' | '.((g:bufExplorerShowRelativePath == 0) ? "Absolute" : "Relative")
    let ret .= ' '.((g:bufExplorerSplitOutPathName == 0) ? "Full" : "Split")." path"
    let ret .= ((g:bufExplorerShowTerminal == 0) ? "" : " | Show terminal")

    return ret
endfunction

" CreateHelp {{{2
function! s:CreateHelp()
    if g:bufExplorerDefaultHelp == 0 && g:bufExplorerDetailedHelp == 0
        let s:firstBufferLine = 1
        return []
    endif

    let header = []

    if g:bufExplorerDetailedHelp == 1
        call add(header, '" Buffer Explorer ('.g:bufexplorer_version.')')
        call add(header, '" --------------------------')
        call add(header, '" <F1> : toggle this help')
        call add(header, '" <enter> or o or Mouse-Double-Click : open buffer under cursor')
        call add(header, '" <shift-enter> or t : open buffer in another tab')
        call add(header, '" a : toggle find active buffer')
        call add(header, '" b : Fast buffer switching with b<any bufnum>')
        call add(header, '" B : toggle if to save/use recent tab or not')
        call add(header, '" d : delete buffer')
        call add(header, '" D : wipe buffer')
        call add(header, '" F : open buffer in another window above the current')
        call add(header, '" f : open buffer in another window below the current')
        call add(header, '" p : toggle splitting of file and path name')
        call add(header, '" q : quit')
        call add(header, '" r : reverse sort')
        call add(header, '" R : toggle showing relative or full paths')
        call add(header, '" s : cycle thru "sort by" fields '.string(s:sort_by).'')
        call add(header, '" S : reverse cycle thru "sort by" fields')
        call add(header, '" T : toggle if to show only buffers for this tab or not')
        call add(header, '" u : toggle showing unlisted buffers')
        call add(header, '" V : open buffer in another window on the left of the current')
        call add(header, '" v : open buffer in another window on the right of the current')
    else
        call add(header, '" Press <F1> for Help')
    endif

    if (!exists("b:displayMode") || b:displayMode != "winmanager") || (b:displayMode == "winmanager" && g:bufExplorerDetailedHelp == 1)
        call add(header, s:GetHelpStatus())
        call add(header, '"=')
    endif

    let s:firstBufferLine = len(header) + 1

    return header
endfunction

" CalculateBufferDetails {{{2
" Calculate `buf`-related details.
function! s:CalculateBufferDetails(buf)
    let buf = a:buf
    let name = bufname(buf._bufnr)
    let buf["hasNoName"] = empty(name)
    if buf.hasNoName
        let name = "[No Name]"
    endif
    let buf.isterminal = getbufvar(buf._bufnr, '&buftype') == 'terminal'
    if buf.isterminal
        let buf.fullname = name
        let buf.isdir = 0
    else
        let buf.fullname = simplify(fnamemodify(name, ':p'))
        let buf.isdir = getftype(buf.fullname) == "dir"
    endif
    if buf.isdir
        " `buf.fullname` ends with a path separator; this will be
        " removed via the first `:h` applied to `buf.fullname` (except
        " for the root directory, where the path separator will remain).
        let parent = fnamemodify(buf.fullname, ':h:h')
        let buf.shortname = fnamemodify(buf.fullname, ':h:t')
        " Special case for root directory: fnamemodify('/', ':h:t') == ''
        if buf.shortname == ''
            let buf.shortname = '.'
        endif
        " Must perform shortening (`:~`, `:.`) before `:h`.
        let buf.homename = fnamemodify(buf.fullname, ':~:h')
        let buf.relativename = fnamemodify(buf.fullname, ':~:.:h')
    else
        let parent = fnamemodify(buf.fullname, ':h')
        let buf.shortname = fnamemodify(buf.fullname, ':t')
        let buf.homename = fnamemodify(buf.fullname, ':~')
        let buf.relativename = fnamemodify(buf.fullname, ':~:.')
    endif
    " `:p` on `parent` adds back the path separator which permits more
    " effective shortening (`:~`, `:.`), but `:h` is required afterward
    " to trim this separator.
    let buf.path = fnamemodify(parent, ':p:~:h')
    let buf.relativepath = fnamemodify(parent, ':p:~:.:h')
endfunction

" GetBufferInfo {{{2
function! s:GetBufferInfo(bufnr)
    redir => bufoutput

    " Show all buffers including the unlisted ones. [!] tells Vim to show the
    " unlisted ones.
    buffers!
    redir END

    if a:bufnr > 0
        " Since we are only interested in this specified buffer remove the
        " other buffers listed.
        let bufoutput = substitute(bufoutput."\n", '^.*\n\(\s*'.a:bufnr.'\>.\{-}\)\n.*', '\1', '')
    endif

    let all = {}

    " Loop over each line in the buffer.
    for line in split(bufoutput, '\n')
        let bits = split(line, '"')

        " Use first and last components after the split on '"', in case a
        " filename with an embedded '"' is present.
        let buf = {"attributes": bits[0], "line": substitute(bits[-1], '\s*', '', '')}
        let buf._bufnr = str2nr(buf.attributes)
        let all[buf._bufnr] = buf
    endfor

    return all
endfunction

" BuildBufferList {{{2
function! s:BuildBufferList()
    let table = []

    " Loop through every buffer.
    for buf in values(s:raw_buffer_listing)
        " `buf.attributes` must exist, but we defer the expensive work of
        " calculating other buffer details (e.g., `buf.fullname`) until we know
        " the user wants to view this buffer.

        " Skip unlisted buffers if we are not to show them.
        if !g:bufExplorerShowUnlisted && buf.attributes =~ "u"
            " Skip unlisted buffers if we are not to show them.
            continue
        endif

        " Ensure buffer details are computed for this buffer.
        if !has_key(buf, 'fullname')
            call s:CalculateBufferDetails(buf)
        endif

        " Skip 'No Name' buffers if we are not to show them.
        if g:bufExplorerShowNoName == 0 && buf.hasNoName
            continue
        endif

        " Are we to show only buffer(s) for this tab?
        if g:bufExplorerShowTabBuffer && (!s:IsInCurrentTab(str2nr(buf.attributes)))
            continue
        endif

        " Skip terminal buffers if we are not to show them.
        if !g:bufExplorerShowTerminal && buf.isterminal
            continue
        endif

        " Skip directory buffers if we are not to show them.
        if !g:bufExplorerShowDirectories && buf.isdir
            continue
        endif

        let row = [buf.attributes]

        if exists("g:loaded_webdevicons")
            let row += [WebDevIconsGetFileTypeSymbol(buf.fullname, buf.isdir)]
        endif

        " Are we to split the path and file name?
        if g:bufExplorerSplitOutPathName
            let type = (g:bufExplorerShowRelativePath) ? "relativepath" : "path"
            let row += [buf.shortname, buf[type]]
        else
            let type = (g:bufExplorerShowRelativePath) ? "relativename" : "homename"
            let row += [buf[type]]
        endif
        let row += [buf.line]
        call add(table, row)
    endfor

    let lines = s:MakeLines(table)
    call setline(s:firstBufferLine, lines)
    call s:SortListing()
endfunction

" MakeLines {{{2
function! s:MakeLines(table)
    if len(a:table) == 0
        return []
    endif
    let lines = []
    " To avoid trailing whitespace, do not pad the final column.
    let numColumnsToPad = len(a:table[0]) - 1
    let maxWidths = repeat([0], numColumnsToPad)
    for row in a:table
        let i = 0
        while i < numColumnsToPad
            let maxWidths[i] = max([maxWidths[i], s:StringWidth(row[i])])
            let i = i + 1
        endwhile
    endfor

    let pads = []
    for w in maxWidths
        call add(pads, repeat(' ', w))
    endfor

    for row in a:table
        let i = 0
        while i < numColumnsToPad
            let row[i] .= strpart(pads[i], s:StringWidth(row[i]))
            let i = i + 1
        endwhile
        call add(lines, join(row, ' '))
    endfor
    return lines
endfunction

" SelectBuffer {{{2
function! s:SelectBuffer(...)
    " Sometimes messages are not cleared when we get here so it looks like an
    " error has occurred when it really has not.
    "echo ""

    let _bufNbr = -1

    if (a:0 == 1) && (a:1 == "ask")
        " Ask the user for input.
        call inputsave()
        let cmd = input("Enter buffer number to switch to: ")
        call inputrestore()

        " Clear the message area from the previous prompt.
        redraw | echo

        if strlen(cmd) > 0
            let _bufNbr = str2nr(cmd)
        else
            call s:Error("Invalid buffer number, try again.")
            return
        endif
    else
        " Are we on a line with a file name?
        if line('.') < s:firstBufferLine
            execute "normal! \<CR>"
            return
        endif

        let _bufNbr = str2nr(getline('.'))

        " Check and see if we are running BufferExplorer via WinManager.
        if exists("b:displayMode") && b:displayMode == "winmanager"
            let _bufName = expand("#"._bufNbr.":p")

            if (a:0 == 1) && (a:1 == "tab")
                call WinManagerFileEdit(_bufName, 1)
            else
                call WinManagerFileEdit(_bufName, 0)
            endif

            return
        endif
    endif

    if bufexists(_bufNbr)
        " Get the tab number where this buffer is located in.
        let tabNbr = s:GetTabNbr(_bufNbr)
        if exists("g:bufExplorerChgWin") && g:bufExplorerChgWin <=winnr("$")
            execute g:bufExplorerChgWin."wincmd w"
            execute "keepjumps keepalt silent b!" _bufNbr

        " Are we supposed to open the selected buffer in a tab?
        elseif (a:0 == 1) && (a:1 == "tab")
            call s:Close()

            " Open a new tab with the selected buffer in it.
            if v:version > 704 || ( v:version == 704 && has('patch2237') )
                " new syntax for last tab as of 7.4.2237
                execute "$tab split +buffer" . _bufNbr
            else
                execute "999tab split +buffer" . _bufNbr
            endif

            " Workaround for the issue mentioned in UpdateTabBufData.
            call s:UpdateTabBufData(_bufNbr)
        " Are we supposed to open the selected buffer in a split?
        elseif (a:0 == 2) && (a:1 == "split")
            call s:Close()
            if (a:2 == "vl")
                execute "vert topleft sb "._bufNbr
            elseif (a:2 == "vr")
                execute "vert belowright sb "._bufNbr
            elseif (a:2 == "st")
                execute "topleft sb "._bufNbr
            else " = sb
                execute "belowright sb "._bufNbr
            endif
        else
            " Request to open in current (BufExplorer) window.
            if g:bufExplorerFindActive && tabNbr > 0
                " Close BufExplorer window and switch to existing tab/window.
                call s:Close()
                execute tabNbr . "tabnext"
                execute bufwinnr(_bufNbr) . "wincmd w"
            else
                " Use BufExplorer window for the buffer.
                execute "keepjumps keepalt silent b!" _bufNbr
            endif
        endif

        " Make the buffer 'listed' again.
        call setbufvar(_bufNbr, "&buflisted", "1")

        " Call any associated function references. g:bufExplorerFuncRef may be
        " an individual function reference or it may be a list containing
        " function references. It will ignore anything that's not a function
        " reference.
        "
        " See  :help FuncRef  for more on function references.
        if exists("g:BufExplorerFuncRef")
            if type(g:BufExplorerFuncRef) == 2
                keepj call g:BufExplorerFuncRef()
            elseif type(g:BufExplorerFuncRef) == 3
                for FncRef in g:BufExplorerFuncRef
                    if type(FncRef) == 2
                        keepj call FncRef()
                    endif
                endfor
            endif
        endif
    else
        call s:Error("Sorry, that buffer no longer exists, please select another")
        call s:DeleteBuffer(_bufNbr, "wipe")
    endif
endfunction

" RemoveBuffer {{{2
function! s:RemoveBuffer(mode)
    " Are we on a line with a file name?
    if line('.') < s:firstBufferLine
        return
    endif

    let mode = a:mode

    " These commands are to temporarily suspend the activity of winmanager.
    if exists("b:displayMode") && b:displayMode == "winmanager"
        call WinManagerSuspendAUs()
    end

    let _bufNbr = str2nr(getline('.'))

    if getbufvar(_bufNbr, '&modified') == 1
        " Calling confirm() requires Vim built with dialog option.
        if !has("dialog_con") && !has("dialog_gui")
            call s:Error("Sorry, no write since last change for buffer "._bufNbr.", unable to delete")
            return
        endif

        let answer = confirm('No write since last change for buffer '._bufNbr.'. Delete anyway?', "&Yes\n&No", 2)

        if a:mode == "delete" && answer == 1
            let mode = "force_delete"
        elseif a:mode == "wipe" && answer == 1
            let mode = "force_wipe"
        else
            return
        endif

    endif

    " Okay, everything is good, delete or wipe the buffer.
    call s:DeleteBuffer(_bufNbr, mode)

    " Reactivate winmanager autocommand activity.
    if exists("b:displayMode") && b:displayMode == "winmanager"
        call WinManagerForceReSize("BufExplorer")
        call WinManagerResumeAUs()
    end
endfunction

" DeleteBuffer {{{2
function! s:DeleteBuffer(buf, mode)
    " This routine assumes that the buffer to be removed is on the current line.
    try
        " Wipe/Delete buffer from Vim.
        if a:mode == "wipe"
            execute "silent bwipe" a:buf
        elseif a:mode == "force_wipe"
            execute "silent bwipe!" a:buf
        elseif a:mode == "force_delete"
            execute "silent bdelete!" a:buf
        else
            execute "silent bdelete" a:buf
        endif

        " Delete the buffer from the list on screen.
        setlocal modifiable
        normal! "_dd
        setlocal nomodifiable

        " Delete the buffer from the raw buffer list.
        unlet s:raw_buffer_listing[a:buf]
    catch
        call s:Error(v:exception)
    endtry
endfunction

" ListedAndCurrentTab {{{2
" Returns whether the specified buffer is both listed and associated with the
" current tab.
function! s:ListedAndCurrentTab(buf)
    return buflisted(a:buf) && s:IsInCurrentTab(a:buf)
endfunction

" Close {{{2
function! s:Close()
    " Get only the listed buffers associated with the current tab.
    let listed = filter(copy(s:MRUList), "s:ListedAndCurrentTab(v:val)")
    if len(listed) == 0
        let listed = filter(range(1, bufnr('$')), "s:ListedAndCurrentTab(v:val)")
    endif

    " If we needed to split the main window, close the split one.
    if s:didSplit
        execute "wincmd c"
    endif

    " Check to see if there are anymore buffers listed.
    if len(listed) == 0
        " Since there are no buffers left to switch to, open a new empty
        " buffers.
        execute "enew"
    else
        " Since there are buffers left to switch to, switch to the previous and
        " then the current.
        for b in reverse(listed[0:1])
            execute "keepjumps silent b ".b
        endfor
    endif

    " Clear any messages.
    echo
endfunction

" ToggleShowTerminal {{{2
function! s:ToggleShowTerminal()
    let g:bufExplorerShowTerminal = !g:bufExplorerShowTerminal
    call s:RebuildBufferList()
    call s:UpdateHelpStatus()
endfunction

" ToggleSplitOutPathName {{{2
function! s:ToggleSplitOutPathName()
    let g:bufExplorerSplitOutPathName = !g:bufExplorerSplitOutPathName
    call s:RebuildBufferList()
    call s:UpdateHelpStatus()
endfunction

" ToggleShowRelativePath {{{2
function! s:ToggleShowRelativePath()
    let g:bufExplorerShowRelativePath = !g:bufExplorerShowRelativePath
    call s:RebuildBufferList()
    call s:UpdateHelpStatus()
endfunction

" ToggleShowTabBuffer {{{2
function! s:ToggleShowTabBuffer()
    let g:bufExplorerShowTabBuffer = !g:bufExplorerShowTabBuffer
    call s:RebuildBufferList(g:bufExplorerShowTabBuffer)
    call s:UpdateHelpStatus()
endfunction

" ToggleOnlyOneTab {{{2
function! s:ToggleOnlyOneTab()
    let g:bufExplorerOnlyOneTab = !g:bufExplorerOnlyOneTab
    call s:RebuildBufferList()
    call s:UpdateHelpStatus()
endfunction

" ToggleShowUnlisted {{{2
function! s:ToggleShowUnlisted()
    let g:bufExplorerShowUnlisted = !g:bufExplorerShowUnlisted
    let num_bufs = s:RebuildBufferList(g:bufExplorerShowUnlisted == 0)
    call s:UpdateHelpStatus()
endfunction

" ToggleFindActive {{{2
function! s:ToggleFindActive()
    let g:bufExplorerFindActive = !g:bufExplorerFindActive
    call s:UpdateHelpStatus()
endfunction

" RebuildBufferList {{{2
function! s:RebuildBufferList(...)
    setlocal modifiable

    let curPos = getpos('.')

    if a:0 && a:000[0] && (line('$') >= s:firstBufferLine)
        " Clear the list first.
        execute "silent keepjumps ".s:firstBufferLine.',$d _'
    endif

    let num_bufs = s:BuildBufferList()

    call setpos('.', curPos)

    setlocal nomodifiable

    return num_bufs
endfunction

" UpdateHelpStatus {{{2
function! s:UpdateHelpStatus()
    setlocal modifiable

    let text = s:GetHelpStatus()
    call setline(s:firstBufferLine - 2, text)

    setlocal nomodifiable
endfunction

" Key_number {{{2
function! s:Key_number(line)
    let _bufnr = str2nr(a:line)
    let key = [printf('%9d', _bufnr)]
    return key
endfunction

" Key_name {{{2
function! s:Key_name(line)
    let _bufnr = str2nr(a:line)
    let buf = s:raw_buffer_listing[_bufnr]
    let key = [buf.shortname, buf.fullname]
    return key
endfunction

" Key_fullpath {{{2
function! s:Key_fullpath(line)
    let _bufnr = str2nr(a:line)
    let buf = s:raw_buffer_listing[_bufnr]
    let key = [buf.fullname]
    return key
endfunction

" Key_extension {{{2
function! s:Key_extension(line)
    let _bufnr = str2nr(a:line)
    let buf = s:raw_buffer_listing[_bufnr]
    let extension = fnamemodify(buf.shortname, ':e')
    let key = [extension, buf.shortname, buf.fullname]
    return key
endfunction

" Key_mru {{{2
function! s:Key_mru(line)
    let _bufnr = str2nr(a:line)
    let buf = s:raw_buffer_listing[_bufnr]
    let pos = index(s:MRUList, _bufnr)
    if pos < 0
        let pos = 0
    endif
    return [printf('%9d', pos), buf.fullname]
endfunction

" SortByKeyFunc {{{2
function! s:SortByKeyFunc(keyFunc)
    let keyedLines = []
    for line in getline(s:firstBufferLine, "$")
        let key = eval(a:keyFunc . '(line)')
        call add(keyedLines, join(key + [line], "\1"))
    endfor

    " Ignore case when sorting by passing `1`:
    call sort(keyedLines, 1)

    if g:bufExplorerReverseSort
        call reverse(keyedLines)
    endif

    let lines = []
    for keyedLine in keyedLines
        call add(lines, split(keyedLine, "\1")[-1])
    endfor

    call setline(s:firstBufferLine, lines)
endfunction

" SortReverse {{{2
function! s:SortReverse()
    let g:bufExplorerReverseSort = !g:bufExplorerReverseSort
    call s:ReSortListing()
endfunction

" SortSelect {{{2
function! s:SortSelect()
    let g:bufExplorerSortBy = get(s:sort_by, index(s:sort_by, g:bufExplorerSortBy) + 1, s:sort_by[0])
    call s:ReSortListing()
endfunction

" ReverseSortSelect {{{2
function! s:ReverseSortSelect()
    let g:bufExplorerSortBy = get(s:sort_by, index(s:sort_by, g:bufExplorerSortBy) - 1, s:sort_by[-1])
    call s:ReSortListing()
endfunction

" ReSortListing {{{2
function! s:ReSortListing()
    setlocal modifiable

    let curPos = getpos('.')

    call s:SortListing()
    call s:UpdateHelpStatus()

    call setpos('.', curPos)

    setlocal nomodifiable
endfunction

" SortListing {{{2
function! s:SortListing()
    call s:SortByKeyFunc("<SID>Key_" . g:bufExplorerSortBy)
endfunction

" MRUListShow {{{2
function! s:MRUListShow()
    echomsg "MRUList=".string(s:MRUList)
endfunction

" Error {{{2
" Display a message using ErrorMsg highlight group.
function! s:Error(msg)
    echohl ErrorMsg
    echomsg a:msg
    echohl None
endfunction

" Warning {{{2
" Display a message using WarningMsg highlight group.
function! s:Warning(msg)
    echohl WarningMsg
    echomsg a:msg
    echohl None
endfunction

" GetTabNbr {{{2
function! s:GetTabNbr(bufNbr)
    " Prefer current tab.
    if bufwinnr(a:bufNbr) > 0
        return tabpagenr()
    endif
    " Searching buffer bufno, in tabs.
    for i in range(tabpagenr("$"))
        if index(tabpagebuflist(i + 1), a:bufNbr) != -1
            return i + 1
        endif
    endfor

    return 0
endfunction

" GetWinNbr" {{{2
function! s:GetWinNbr(tabNbr, bufNbr)
    " window number in tabpage.
    let tablist = tabpagebuflist(a:tabNbr)
    " Number:     0
    " String:     1
    " Funcref:    2
    " List:       3
    " Dictionary: 4
    " Float:      5
    if type(tablist) == 3
        return index(tabpagebuflist(a:tabNbr), a:bufNbr) + 1
    else
        return 1
    endif
endfunction

" StringWidth" {{{2
if exists('*strwidth')
    function s:StringWidth(s)
        return strwidth(a:s)
    endfunction
else
    function s:StringWidth(s)
        return len(a:s)
    endfunction
endif

" Winmanager Integration {{{2
let g:BufExplorer_title = "\[Buf\ List\]"
call s:Set("g:bufExplorerResize", 1)
call s:Set("g:bufExplorerMaxHeight", 25) " Handles dynamic resizing of the window.

" function! to start display. Set the mode to 'winmanager' for this buffer.
" This is to figure out how this plugin was called. In a standalone fashion
" or by winmanager.
function! BufExplorer_Start()
    let b:displayMode = "winmanager"
    call s:SetLocalSettings()
    call BufExplorer()
endfunction

" Returns whether the display is okay or not.
function! BufExplorer_IsValid()
    return 0
endfunction

" Handles dynamic refreshing of the window.
function! BufExplorer_Refresh()
    let b:displayMode = "winmanager"
    call s:SetLocalSettings()
    call BufExplorer()
endfunction

function! BufExplorer_ReSize()
    if !g:bufExplorerResize
        return
    end

    let nlines = min([line("$"), g:bufExplorerMaxHeight])

    execute nlines." wincmd _"

    " The following lines restore the layout so that the last file line is also
    " the last window line. Sometimes, when a line is deleted, although the
    " window size is exactly equal to the number of lines in the file, some of
    " the lines are pushed up and we see some lagging '~'s.
    let pres = getpos(".")

    normal! $

    let _scr = &scrolloff
    let &scrolloff = 0

    normal! z-

    let &scrolloff = _scr

    call setpos(".", pres)
endfunction

" Default values {{{2
call s:Set("g:bufExplorerDisableDefaultKeyMapping", 0)  " Do not disable default key mappings.
call s:Set("g:bufExplorerDefaultHelp", 1)               " Show default help?
call s:Set("g:bufExplorerDetailedHelp", 0)              " Show detailed help?
call s:Set("g:bufExplorerFindActive", 1)                " When selecting an active buffer, take you to the window where it is active?
call s:Set("g:bufExplorerOnlyOneTab", 1)                " If ShowTabBuffer = 1, only store the most recent tab for this buffer.
call s:Set("g:bufExplorerReverseSort", 0)               " Sort in reverse order by default?
call s:Set("g:bufExplorerShowDirectories", 1)           " (Dir's are added by commands like ':e .')
call s:Set("g:bufExplorerShowRelativePath", 0)          " Show listings with relative or absolute paths?
call s:Set("g:bufExplorerShowTabBuffer", 0)             " Show only buffer(s) for this tab?
call s:Set("g:bufExplorerShowUnlisted", 0)              " Show unlisted buffers?
call s:Set("g:bufExplorerShowNoName", 0)                " Show 'No Name' buffers?
call s:Set("g:bufExplorerSortBy", "mru")                " Sorting methods are in s:sort_by:
call s:Set("g:bufExplorerSplitBelow", &splitbelow)      " Should horizontal splits be below or above current window?
call s:Set("g:bufExplorerSplitOutPathName", 1)          " Split out path and file name?
call s:Set("g:bufExplorerSplitRight", &splitright)      " Should vertical splits be on the right or left of current window?
call s:Set("g:bufExplorerSplitVertSize", 0)             " Height for a vertical split. If <=0, default Vim size is used.
call s:Set("g:bufExplorerSplitHorzSize", 0)             " Height for a horizontal split. If <=0, default Vim size is used.
call s:Set("g:bufExplorerShowTerminal", 1)              " Show terminal buffers?

" Default key mapping {{{2
if !hasmapto('BufExplorer') && g:bufExplorerDisableDefaultKeyMapping == 0
    nnoremap <script> <silent> <unique> <Leader>be :BufExplorer<CR>
endif

if !hasmapto('ToggleBufExplorer') && g:bufExplorerDisableDefaultKeyMapping == 0
    nnoremap <script> <silent> <unique> <Leader>bt :ToggleBufExplorer<CR>
endif

if !hasmapto('BufExplorerHorizontalSplit') && g:bufExplorerDisableDefaultKeyMapping == 0
    nnoremap <script> <silent> <unique> <Leader>bs :BufExplorerHorizontalSplit<CR>
endif

if !hasmapto('BufExplorerVerticalSplit') && g:bufExplorerDisableDefaultKeyMapping == 0
    nnoremap <script> <silent> <unique> <Leader>bv :BufExplorerVerticalSplit<CR>
endif

" vim:ft=vim foldmethod=marker sw=4