Improved display of plain text messages and text to HTML conversion (#1488937)

Now instead of <pre> we use <div class="pre"> styled with monospace
font. We replace whitespace characters with non-breaking spaces where
needed. I.e. plain text is always unwrappable, until it uses format=flowed,
in such a case only flowed paragraphs are wrappable.

Also conversion of text to HTML in compose editor was modified in the same way.

1 files changed, 277 insertions, 0 deletions

diff --git a/program/lib/Roundcube/rcube_text2html.php b/program/lib/Roundcube/rcube_text2html.php
new file mode 100644
index 000000000..5da771ac8
--- /dev/null
+++ b/program/lib/Roundcube/rcube_text2html.php
@@ -0,0 +1,277 @@
+<?php
+
+/**
+ +-----------------------------------------------------------------------+
+ | This file is part of the Roundcube Webmail client                     |
+ | Copyright (C) 2008-2014, The Roundcube Dev Team                       |
+ |                                                                       |
+ | Licensed under the GNU General Public License version 3 or            |
+ | any later version with exceptions for skins & plugins.                |
+ | See the README file for a full license statement.                     |
+ |                                                                       |
+ | PURPOSE:                                                              |
+ |   Converts plain text to HTML                                         |
+ +-----------------------------------------------------------------------+
+ | Author: Aleksander Machniak <alec@alec.pl>                            |
+ +-----------------------------------------------------------------------+
+ */
+
+/**
+ * Converts plain text to HTML
+ *
+ * @package    Framework
+ * @subpackage Utils
+ */
+class rcube_text2html
+{
+    /**
+     * Contains the HTML content after conversion.
+     *
+     * @var string $html
+     */
+    protected $html;
+
+    /**
+     * Contains the plain text.
+     *
+     * @var string $text
+     */
+    protected $text;
+
+    /**
+     * Configuration
+     *
+     * @var array $config
+     */
+    protected $config = array(
+        // non-breaking space
+        'space'  => "\xC2\xA0",
+        // enables format=flowed parser
+        'flowed' => false,
+        // enables wrapping for non-flowed text
+        'wrap'   => false,
+        // line-break tag
+        'break'  => "<br>\n",
+        // prefix and suffix (wrapper element)
+        'begin'  => '<div class="pre">',
+        'end'    => '</end>',
+        // enables links replacement
+        'links'  => true,
+    );
+
+
+    /**
+     * Constructor.
+     *
+     * If the plain text source string (or file) is supplied, the class
+     * will instantiate with that source propagated, all that has
+     * to be done it to call get_html().
+     *
+     * @param string  $source    Plain text
+     * @param boolean $from_file Indicates $source is a file to pull content from
+     * @param array   $config    Class configuration
+     */
+    function __construct($source = '', $from_file = false, $config = array())
+    {
+        if (!empty($source)) {
+            $this->set_text($source, $from_file);
+        }
+
+        if (!empty($config) && is_array($config)) {
+            $this->config = array_merge($this->config, $config);
+        }
+    }
+
+    /**
+     * Loads source text into memory, either from $source string or a file.
+     *
+     * @param string  $source    Plain text
+     * @param boolean $from_file Indicates $source is a file to pull content from
+     */
+    function set_text($source, $from_file = false)
+    {
+        if ($from_file && file_exists($source)) {
+            $this->text = file_get_contents($source);
+        }
+        else {
+            $this->text = $source;
+        }
+
+        $this->_converted = false;
+    }
+
+    /**
+     * Returns the HTML content.
+     *
+     * @return string HTML content
+     */
+    function get_html()
+    {
+        if (!$this->_converted) {
+            $this->_convert();
+        }
+
+        return $this->html;
+    }
+
+    /**
+     * Prints the HTML.
+     */
+    function print_html()
+    {
+        print $this->get_html();
+    }
+
+    /**
+     * Workhorse function that does actual conversion (calls _converter() method).
+     */
+    protected function _convert()
+    {
+        $text = stripslashes($this->text);
+
+        // Convert TXT to HTML
+        $this->html       = $this->_converter($text);
+        $this->_converted = true;
+    }
+
+    /**
+     * Workhorse function that does actual conversion.
+     *
+     * @param string Plain text
+     */
+    protected function _converter($text)
+    {
+        // make links and email-addresses clickable
+        $attribs  = array('link_attribs' => array('rel' => 'noreferrer', 'target' => '_blank'));
+        $replacer = new rcmail_string_replacer($attribs);
+
+        if ($this->config['flowed']) {
+            $flowed_char = 0x01;
+            $text        = rcube_mime::unfold_flowed($text, chr($flowed_char));
+        }
+
+        // search for patterns like links and e-mail addresses and replace with tokens
+        if ($this->config['links']) {
+            $text = $replacer->replace($text);
+        }
+
+        // split body into single lines
+        $text        = preg_split('/\r?\n/', $text);
+        $quote_level = 0;
+        $last        = -1;
+
+        // find/mark quoted lines...
+        for ($n=0, $cnt=count($text); $n < $cnt; $n++) {
+            $flowed = false;
+            if ($this->config['flowed'] && ord($text[0]) == $flowed_char) {
+                $flowed   = true;
+                $text[$n] = substr($text[$n], 1);
+            }
+
+            if ($text[$n][0] == '>' && preg_match('/^(>+ {0,1})+/', $text[$n], $regs)) {
+                $q        = substr_count($regs[0], '>');
+                $text[$n] = substr($text[$n], strlen($regs[0]));
+                $text[$n] = $this->_convert_line($text[$n], $flowed || $this->config['wrap']);
+
+                if ($q > $quote_level) {
+                    $text[$n] = $replacer->get_replacement($replacer->add(
+                        str_repeat('<blockquote>', $q - $quote_level))) . $text[$n];
+                    $last = $n;
+                }
+                else if ($q < $quote_level) {
+                    $text[$n] = $replacer->get_replacement($replacer->add(
+                        str_repeat('</blockquote>', $quote_level - $q))) . $text[$n];
+                    $last = $n;
+                }
+            }
+            else {
+                $text[$n] = $this->_convert_line($text[$n], $flowed || $this->config['wrap']);
+                $q = 0;
+
+                if ($quote_level > 0) {
+                    $text[$n] = $replacer->get_replacement($replacer->add(
+                        str_repeat('</blockquote>', $quote_level))) . $text[$n];
+                }
+            }
+
+            $quote_level = $q;
+        }
+
+        if ($quote_level > 0) {
+            $text[$n] = $replacer->get_replacement($replacer->add(
+                str_repeat('</blockquote>', $quote_level))) . $text[$n];
+        }
+
+        $text = join("\n", $text);
+
+        // colorize signature (up to <sig_max_lines> lines)
+        $len = strlen($text);
+        $sig_max_lines = rcube::get_instance()->config->get('sig_max_lines', 15);
+
+        while (($sp = strrpos($text, "-- \n", $sp ? -$len+$sp-1 : 0)) !== false) {
+            if ($sp == 0 || $text[$sp-1] == "\n") {
+                // do not touch blocks with more that X lines
+                if (substr_count($text, "\n", $sp) < $sig_max_lines) {
+                    $text = substr($text, 0, max(0, $sp))
+                        .'<span class="sig">'.substr($text, $sp).'</span>';
+                }
+
+                break;
+            }
+        }
+
+        // insert url/mailto links and citation tags
+        $text = $replacer->resolve($text);
+
+        // replace \n before </blockquote>
+        $text = str_replace("\n</blockquote>", "</blockquote>", $text);
+
+        // replace line breaks
+        $text = str_replace("\n", $this->config['break'], $text);
+
+        return $this->config['begin'] . $text . $this->config['end'];
+    }
+
+    /**
+     * Converts spaces in line of text
+     */
+    protected function _convert_line($text, $is_flowed)
+    {
+        static $table;
+
+        if (empty($table)) {
+            $table = get_html_translation_table(HTML_SPECIALCHARS);
+            unset($table['?']);
+        }
+
+        // skip signature separator
+        if ($text == '-- ') {
+            return $text;
+        }
+
+        // replace HTML special characters
+        $text = strtr($text, $table);
+
+        $nbsp = $this->config['space'];
+
+        // replace some whitespace characters
+        $text = str_replace(array("\r", "\t"), array('', '    '), $text);
+
+        // replace spaces with non-breaking spaces
+        if ($is_flowed) {
+            $text = preg_replace_callback('/(^|[^ ])( +)/', function($matches) {
+                    if (!strlen($matches[2])) {
+                        return str_repeat($nbsp, strlen($matches[2]));
+                    }
+                    else {
+                        return $matches[1] . ' ' . str_repeat($nbsp, strlen($matches[2])-1);
+                    }
+                }, $text);
+        }
+        else {
+            $text = str_replace(' ', $nbsp, $text);
+        }
+
+        return $text;
+    }
+}