path: root/modules/text-highlight/e-mail-formatter-text-highlight.c

/*
 * text-highlight.c
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "e-mail-formatter-text-highlight.h"
#include "languages.h"

#include <em-format/e-mail-formatter-extension.h>
#include <em-format/e-mail-formatter.h>
#include <em-format/e-mail-part-utils.h>
#include <e-util/e-util.h>

#include <libebackend/libebackend.h>
#include <libedataserver/libedataserver.h>

#include <glib/gi18n-lib.h>
#include <camel/camel.h>

typedef EMailFormatterExtension EMailFormatterTextHighlight;
typedef EMailFormatterExtensionClass EMailFormatterTextHighlightClass;

typedef EExtension EMailFormatterTextHighlightLoader;
typedef EExtensionClass EMailFormatterTextHighlightLoaderClass;

typedef struct _TextHighlightClosure TextHighlightClosure;

struct _TextHighlightClosure {
    CamelStream *read_stream;
    GOutputStream *output_stream;
    GCancellable *cancellable;
    GError *error;
};

GType e_mail_formatter_text_highlight_get_type (void);

G_DEFINE_DYNAMIC_TYPE (
    EMailFormatterTextHighlight,
    e_mail_formatter_text_highlight,
    E_TYPE_MAIL_FORMATTER_EXTENSION)

static gchar *
get_syntax (EMailPart *part,
            const gchar *uri)
{
    gchar *syntax = NULL;
    CamelContentType *ct = NULL;
    CamelMimePart *mime_part;

    mime_part = e_mail_part_ref_mime_part (part);

    if (uri) {
        SoupURI *soup_uri = soup_uri_new (uri);
        GHashTable *query = soup_form_decode (soup_uri->query);

        syntax = g_hash_table_lookup (query, "__formatas");
        if (syntax) {
            syntax = g_strdup (syntax);
        }
        g_hash_table_destroy (query);
        soup_uri_free (soup_uri);
    }

    /* Try to detect syntax by content-type first */
    if (syntax == NULL) {
        ct = camel_mime_part_get_content_type (mime_part);
        if (ct) {
            gchar *mime_type = camel_content_type_simple (ct);

            syntax = (gchar *) get_syntax_for_mime_type (mime_type);
            syntax = syntax ? g_strdup (syntax) : NULL;
            g_free (mime_type);
        }
    }

    /* If it fails or the content type too generic, try to detect it by
     * filename extension */
    if (syntax == NULL ||
        (ct != NULL &&
         (camel_content_type_is (ct, "application", "octet-stream") ||
         (camel_content_type_is (ct, "text", "plain"))))) {
        const gchar *filename;

        filename = camel_mime_part_get_filename (mime_part);
        if (filename != NULL) {
            gchar *ext = g_strrstr (filename, ".");
            if (ext != NULL) {
                g_free (syntax);
                syntax = (gchar *) get_syntax_for_ext (ext + 1);
                syntax = syntax ? g_strdup (syntax) : NULL;
            }
        }
    }

    /* Out of ideas - use plain text */
    if (syntax == NULL) {
        syntax = g_strdup ("txt");
    }

    g_object_unref (mime_part);

    return syntax;
}

static gpointer
text_hightlight_read_data_thread (gpointer user_data)
{
    TextHighlightClosure *closure = user_data;
    gchar buffer[10240];

    g_return_val_if_fail (closure != NULL, NULL);

    while (!camel_stream_eos (closure->read_stream) &&
           !g_cancellable_set_error_if_cancelled (closure->cancellable, &closure->error)) {
        gssize read;
        gsize wrote = 0;

        read = camel_stream_read (closure->read_stream, buffer, 10240, closure->cancellable, &closure->error);
        if (read < 0 || closure->error)
            break;

        if (!g_output_stream_write_all (closure->output_stream, buffer, read, &wrote, closure->cancellable, &closure->error) ||
            (gssize) wrote != read || closure->error)
            break;
    }

    return NULL;
}

static gboolean
text_highlight_feed_data (GOutputStream *output_stream,
                          CamelDataWrapper *data_wrapper,
                          gint pipe_stdin,
                          gint pipe_stdout,
                          GCancellable *cancellable,
                          GError **error)
{
    TextHighlightClosure closure;
    CamelContentType *content_type;
    CamelStream *write_stream;
    gboolean success = TRUE;
    GThread *thread;

    closure.read_stream = camel_stream_fs_new_with_fd (pipe_stdout);
    closure.output_stream = output_stream;
    closure.cancellable = cancellable;
    closure.error = NULL;

    write_stream = camel_stream_fs_new_with_fd (pipe_stdin);

    thread = g_thread_new (NULL, text_hightlight_read_data_thread, &closure);

    content_type = camel_data_wrapper_get_mime_type_field (data_wrapper);
    if (content_type) {
        const gchar *charset = camel_content_type_param (content_type, "charset");

        /* Convert to UTF-8 charset, if needed, which the 'highlight' expects;
           it can cope with non-UTF-8 letters, thus no need for a content UTF-8-validation */
        if (charset && g_ascii_strcasecmp (charset, "utf-8") != 0) {
            CamelMimeFilter *filter;

            filter = camel_mime_filter_charset_new (charset, "UTF-8");
            if (filter != NULL) {
                CamelStream *filtered = camel_stream_filter_new (write_stream);

                if (filtered) {
                    camel_stream_filter_add (CAMEL_STREAM_FILTER (filtered), filter);
                    g_object_unref (write_stream);
                    write_stream = filtered;
                }

                g_object_unref (filter);
            }
        }
    }

    if (camel_data_wrapper_decode_to_stream_sync (data_wrapper, write_stream, cancellable, error) < 0) {
        g_cancellable_cancel (cancellable);
        success = FALSE;
    } else {
        /* Close the stream, thus the highlight knows no more data will come */
        g_clear_object (&write_stream);
    }

    g_thread_join (thread);

    g_clear_object (&closure.read_stream);
    g_clear_object (&write_stream);

    if (closure.error) {
        if (error && !*error)
            g_propagate_error (error, closure.error);
        else
            g_clear_error (&closure.error);

        return FALSE;
    }

    return success;
}

static gboolean
emfe_text_highlight_format (EMailFormatterExtension *extension,
                            EMailFormatter *formatter,
                            EMailFormatterContext *context,
                            EMailPart *part,
                            GOutputStream *stream,
                            GCancellable *cancellable)
{
    CamelMimePart *mime_part;
    CamelContentType *ct;
    gboolean success = FALSE;

    mime_part = e_mail_part_ref_mime_part (part);
    ct = camel_mime_part_get_content_type (mime_part);

    /* Don't format text/html unless it's an attachment */
    if (ct && camel_content_type_is (ct, "text", "html")) {
        const CamelContentDisposition *disp;

        disp = camel_mime_part_get_content_disposition (mime_part);

        if (disp == NULL)
            goto exit;

        if (g_strcmp0 (disp->disposition, "attachment") != 0)
            goto exit;
    }

    if (context->mode == E_MAIL_FORMATTER_MODE_PRINTING) {
        /* Don't interfere with printing. */
        goto exit;

    } else if (context->mode == E_MAIL_FORMATTER_MODE_RAW) {
        gint pipe_stdin, pipe_stdout;
        GPid pid;
        CamelDataWrapper *dw;
        gchar *font_family, *font_size, *syntax;
        PangoFontDescription *fd;
        GSettings *settings;
        gchar *font = NULL;

        const gchar *argv[] = {
            HIGHLIGHT_COMMAND,
            NULL,   /* --font= */
            NULL,   /* --font-size= */
            NULL,   /* --syntax= */
            "--out-format=html",
            "--include-style",
            "--inline-css",
            "--style=bclear",
            "--failsafe",
            NULL };

        dw = camel_medium_get_content (CAMEL_MEDIUM (mime_part));
        if (dw == NULL)
            goto exit;

        syntax = get_syntax (part, context->uri);

        /* Use the traditional text/plain formatter for plain-text */
        if (g_strcmp0 (syntax, "txt") == 0) {
            g_free (syntax);
            goto exit;
        }

        settings = g_settings_new ("org.gnome.evolution.mail");
        if (g_settings_get_boolean (settings, "use-custom-font"))
            font = g_settings_get_string (
                settings, "monospace-font");
        g_object_unref (settings);

        if (font == NULL) {
            settings = g_settings_new (
                "org.gnome.desktop.interface");
            font = g_settings_get_string (
                settings, "monospace-font-name");
            g_object_unref (settings);
        }

        if (font == NULL)
            font = g_strdup ("monospace 10");

        fd = pango_font_description_from_string (font);

        g_free (font);

        font_family = g_strdup_printf (
            "--font='%s'",
            pango_font_description_get_family (fd));
        font_size = g_strdup_printf (
            "--font-size=%d",
            pango_font_description_get_size (fd) / PANGO_SCALE);

        argv[1] = font_family;
        argv[2] = font_size;
        argv[3] = g_strdup_printf ("--syntax=%s", syntax);
        g_free (syntax);

        success = g_spawn_async_with_pipes (
            NULL, (gchar **) argv, NULL, 0, NULL, NULL,
            &pid, &pipe_stdin, &pipe_stdout, NULL, NULL);

        if (success) {
            GError *local_error = NULL;

            success = text_highlight_feed_data (
                stream, dw,
                pipe_stdin, pipe_stdout,
                cancellable, &local_error);

            if (g_error_matches (
                local_error, G_IO_ERROR,
                G_IO_ERROR_CANCELLED)) {
                /* Do nothing. */

            } else if (local_error != NULL) {
                g_warning (
                    "%s: %s", G_STRFUNC,
                    local_error->message);
            }

            g_clear_error (&local_error);

            g_spawn_close_pid (pid);
        }

        if (!success) {
            /* We can't call e_mail_formatter_format_as on text/plain,
             * because text-highlight is registered as an handler for
             * text/plain, so we would end up in an endless recursion.
             *
             * Just return FALSE here and EMailFormatter will automatically
             * fall back to the default text/plain formatter */
            if (camel_content_type_is (ct, "text", "plain")) {
                g_free (font_family);
                g_free (font_size);
                g_free ((gchar *) argv[3]);
                pango_font_description_free (fd);
                goto exit;

            } else {
                /* In case of any other content, force use of
                 * text/plain formatter, because returning FALSE
                 * for text/x-patch or application/php would show
                 * an error, as there is no other handler registered
                 * for these */
                e_mail_formatter_format_as (
                    formatter, context, part, stream,
                    "application/vnd.evolution.plaintext",
                    cancellable);
            }
        }

        g_free (font_family);
        g_free (font_size);
        g_free ((gchar *) argv[3]);
        pango_font_description_free (fd);

    } else {
        CamelFolder *folder;
        const gchar *message_uid;
        const gchar *default_charset, *charset;
        gchar *uri, *str;
        gchar *syntax;

        folder = e_mail_part_list_get_folder (context->part_list);
        message_uid = e_mail_part_list_get_message_uid (context->part_list);
        default_charset = e_mail_formatter_get_default_charset (formatter);
        charset = e_mail_formatter_get_charset (formatter);

        if (!default_charset)
            default_charset = "";
        if (!charset)
            charset = "";

        syntax = get_syntax (part, NULL);

        uri = e_mail_part_build_uri (
            folder, message_uid,
            "part_id", G_TYPE_STRING, e_mail_part_get_id (part),
            "mode", G_TYPE_INT, E_MAIL_FORMATTER_MODE_RAW,
            "__formatas", G_TYPE_STRING, syntax,
            "formatter_default_charset", G_TYPE_STRING, default_charset,
            "formatter_charset", G_TYPE_STRING, charset,
            NULL);

        g_free (syntax);

        str = g_strdup_printf (
            "<div class=\"part-container-nostyle\" >"
            "<iframe width=\"100%%\" height=\"10\""
            " id=\"%s\" name=\"%s\" "
            " class=\"-e-mail-formatter-frame-color -e-web-view-background-color\" "
            " frameborder=\"0\" src=\"%s\" "
            " style=\"border: 1px solid;\">"
            "</iframe>"
            "</div>",
            e_mail_part_get_id (part),
            e_mail_part_get_id (part),
            uri);

        g_output_stream_write_all (
            stream, str, strlen (str),
            NULL, cancellable, NULL);

        g_free (str);
        g_free (uri);
    }

    success = TRUE;

exit:
    g_object_unref (mime_part);

    return success;
}

static void
e_mail_formatter_text_highlight_class_init (EMailFormatterExtensionClass *class)
{
    class->display_name = _("Text Highlight");
    class->description = _("Syntax highlighting of mail parts");
    class->mime_types = get_mime_types ();
    class->format = emfe_text_highlight_format;
}

static void
e_mail_formatter_text_highlight_class_finalize (EMailFormatterExtensionClass *class)
{
}

static void
e_mail_formatter_text_highlight_init (EMailFormatterExtension *extension)
{
}

void
e_mail_formatter_text_highlight_type_register (GTypeModule *type_module)
{
    e_mail_formatter_text_highlight_register_type (type_module);
}