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*(.*)$')
  55         if headers then
  56             local level = headers:len()
  57             if level <= 3 then
  58                 -- Avoid <h1> for level 1 headings, because it causes a
  59                 -- newpage in the default stylesheet epub.css
  60                 return "<h" .. level + 1 .. ">" .. util.htmlEscape(text) .. "</h" .. level .. ">", false
  61             end
  62         end
  63
  64         text = line:match("^%*%s+(.*)$")
  65         if text then
  66             return "<li>" .. util.htmlEscape(text) .. "</li>", true
  67         end
  68
  69         text = line:match('^>(.*)$')
  70         if text then
  71             return "<blockquote>" .. util.htmlEscape(text) .. "</blockquote>", true
  72         end
  73
  74         return "<p>" .. util.htmlEscape(line) .. "</p>"
  75     end
  76
  77     o:write("<html><body>\n")
  78     local in_list = false
  79     local list
  80     local written_line = false
  81     for line in i:lines() do
  82         line, list = parseLine(line)
  83         if list and not in_list then
  84             line = "<ul>" .. line
  85         elseif in_list and not list then
  86             line = "</ul>\n" .. line
  87         end
  88         in_list = list
  89         o:write(line .. "\n")
  90         written_line = true
  91     end
  92     i:close()
  93     if not written_line then
  94         -- work around CRE not rendering empty html documents properly
  95         o:write(_("[Empty gemini document]\n"))
  96     end
  97     o:write("</body></html>")
  98 end
  99
 100 function GeminiDocument:init()
 101     self.tmp_html_file = os.tmpname() .. ".html"
 102     if not self.tmp_html_file then
 103         error(_("Failed to create temporary file for gmi -> html conversion."))
 104     end
 105     local i = io.open(self.file, "r")
 106     local o = io.open(self.tmp_html_file, "w")
 107     convertGmi(i, o)
 108     o:close()
 109     local gemfile = self.file
 110     self.file = self.tmp_html_file
 111     CreDocument.init(self)
 112     self.file = gemfile
 113
 114     -- XXX: hack; uses that only these methods read self.file
 115     for _i,method in ipairs({"loadDocument","getNativePageDimensions","_readMetadata","getFullPageHash","renderPage"}) do
 116         self[method] = function(slf, ...)
 117             slf.file = slf.tmp_html_file
 118             local ok, re = pcall(CreDocument[method], slf, ...)
 119             slf.file = gemfile
 120             if ok then
 121                 return re
 122             else
 123                 logger.err("wrapped credocument call failed", method, re)
 124                 return false
 125             end
 126         end
 127     end
 128 end
 129
 130 function GeminiDocument:close()
 131     CreDocument.close(self)
 132     FileManager:deleteFile(self.tmp_html_file, true)
 133 end
 134
 135 return GeminiDocument