geminidocument.lua

   1 local CreDocument = require("document/credocument")
   2 local FileManager = require("apps/filemanager/filemanager")
   3 local url = require("socket.url")
   4 local util = require("util")
   5 local logger = require("logger")
   6 local _ = require("gettext")
   7 local T = require("ffi/util").template
   8
   9 local GeminiDocument = CreDocument:extend{}
  10
  11 local function convertGmi(i, o)
  12     local pre = false
  13     local function parseLine(line)
  14         -- strip ANSI CSI sequences (used in some gemtext documents for
  15         -- colour, which we do not try to support)
  16         line = line:gsub("%\x1b%[[ -?]*[@-~]","")
  17
  18         local alt = line:match("^```%s*(.*)$")
  19         if alt then
  20             if not pre then
  21                 pre = true
  22                 -- use <small> to improve chance that wide ascii art will fit
  23                 -- on the screen
  24                 return "<small><pre>", false
  25             else
  26                 pre = false
  27                 return "</pre></small>", false
  28             end
  29         end
  30         if pre then
  31             return util.htmlEscape(line), false
  32         end
  33
  34         if line:match("^%s*$") then
  35             return "<br/>", false
  36         end
  37
  38         local link, desc
  39         link = line:match('^=>%s*([^%s]+)%s*$')
  40         if not link then
  41             link,desc = line:match('^=>%s*([^%s]+)%s+(.+)$')
  42         end
  43         if link then
  44             local purl = url.parse(link)
  45             desc = desc or link
  46             desc = util.htmlEscape(desc)
  47             if purl.scheme and purl.scheme ~= "gemini" then
  48                 desc = desc .. T(" <em>[%1]</em>", purl.scheme)
  49             end
  50             return '<li><a href="' .. link .. '">' .. desc .. '</a></li>', true
  51         end
  52
  53         local headers, text
  54         headers,text = line:match('^(#+)%s*(.*)$')
  55         if headers then
  56             local level = headers:len()
  57             if level <= 3 then
  58                 return "<h" .. level .. ">" .. util.htmlEscape(text) .. "</h" .. level .. ">", false
  59             end
  60         end
  61
  62         text = line:match("^%*%s+(.*)$")
  63         if text then
  64             return "<li>" .. util.htmlEscape(text) .. "</li>", true
  65         end
  66
  67         text = line:match('^>(.*)$')
  68         if text then
  69             return "<blockquote>" .. util.htmlEscape(text) .. "</blockquote>", true
  70         end
  71
  72         return "<p>" .. util.htmlEscape(line) .. "</p>"
  73     end
  74
  75     o:write("<html>\n")
  76     -- Override css to not require page breaks on headers,
  77     -- and improve contrast for links.
  78     o:write([[
  79 <head><style>
  80 h1, h2, h3 {
  81     page-break-before: auto;
  82 }
  83 a {
  84     text-decoration: underline; color: #505050;
  85 }
  86 </style></head>
  87 ]])
  88     o:write("<body>\n")
  89     local in_list = false
  90     local list
  91     local written_line = false
  92     for line in i:lines() do
  93         line, list = parseLine(line)
  94         if list and not in_list then
  95             line = "<ul>" .. line
  96         elseif in_list and not list then
  97             line = "</ul>\n" .. line
  98         end
  99         in_list = list
 100         o:write(line .. "\n")
 101         written_line = true
 102     end
 103     i:close()
 104     if not written_line then
 105         -- work around CRE not rendering empty html documents properly
 106         o:write(_("[Empty gemini document]\n"))
 107     end
 108     o:write("</body></html>")
 109 end
 110
 111 function GeminiDocument:init()
 112     self.tmp_html_file = os.tmpname() .. ".html"
 113     if not self.tmp_html_file then
 114         error(_("Failed to create temporary file for gmi -> html conversion."))
 115     end
 116     local i = io.open(self.file, "r")
 117     local o = io.open(self.tmp_html_file, "w")
 118     convertGmi(i, o)
 119     o:close()
 120     local gemfile = self.file
 121     self.file = self.tmp_html_file
 122     CreDocument.init(self)
 123     self.file = gemfile
 124
 125     -- XXX: hack; uses that only these methods read self.file
 126     for _i,method in ipairs({"loadDocument","getNativePageDimensions","_readMetadata","getFullPageHash","renderPage"}) do
 127         self[method] = function(slf, ...)
 128             slf.file = slf.tmp_html_file
 129             local ok, re = pcall(CreDocument[method], slf, ...)
 130             slf.file = gemfile
 131             if ok then
 132                 return re
 133             else
 134                 logger.err("wrapped credocument call failed", method, re)
 135                 return false
 136             end
 137         end
 138     end
 139 end
 140
 141 function GeminiDocument:close()
 142     CreDocument.close(self)
 143     FileManager:deleteFile(self.tmp_html_file, true)
 144 end
 145
 146 return GeminiDocument