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Diffstat (limited to 'lib/gs-download-utils.c')
| -rw-r--r-- | lib/gs-download-utils.c | 870 |
1 files changed, 870 insertions, 0 deletions
diff --git a/lib/gs-download-utils.c b/lib/gs-download-utils.c new file mode 100644 index 0000000..4949064 --- /dev/null +++ b/lib/gs-download-utils.c @@ -0,0 +1,870 @@ +/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- + * vi:set noexpandtab tabstop=8 shiftwidth=8: + * + * Copyright (C) 2021, 2022 Endless OS Foundation LLC + * + * Author: Philip Withnall <pwithnall@endlessos.org> + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +/** + * SECTION:gs-download-utils + * @short_description: Download and HTTP utilities + * + * A set of utilities for downloading things and doing HTTP requests. + * + * Since: 42 + */ + +#include "config.h" + +#include <gio/gio.h> +#include <glib.h> +#include <glib-object.h> +#include <glib/gi18n.h> +#include <libsoup/soup.h> + +#include "gs-download-utils.h" +#include "gs-utils.h" + +G_DEFINE_QUARK (gs-download-error-quark, gs_download_error) + +/** + * gs_build_soup_session: + * + * Build a new #SoupSession configured with the gnome-software user agent. + * + * A new #SoupSession should be used for each independent download context, such + * as in different plugins. Each #SoupSession caches HTTP connections and + * authentication information, and these likely needn’t be shared between + * plugins. Using separate sessions reduces thread contention. + * + * Returns: (transfer full): a new #SoupSession + * Since: 42 + */ +SoupSession * +gs_build_soup_session (void) +{ + return soup_session_new_with_options ("user-agent", gs_user_agent (), + "timeout", 10, + NULL); +} + +/* See https://httpwg.org/specs/rfc7231.html#http.date + * For example: Sun, 06 Nov 1994 08:49:37 GMT */ +static gchar * +date_time_to_rfc7231 (GDateTime *date_time) +{ +#if SOUP_CHECK_VERSION(3, 0, 0) + return soup_date_time_to_string (date_time, SOUP_DATE_HTTP); +#else + const gchar *day_names[] = { "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun" }; + const gchar *month_names[] = { "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" }; + + /* We can’t just use g_date_time_format() here because its output + * (particularly day and month names) is locale-dependent. + * #SoupDate is also a pain to use because there’s no easy way to + * convert from a #GDateTime with libsoup-2.4, while preserving the timezone. */ + g_autofree gchar *time_str = g_date_time_format (date_time, "%H:%M:%S %Z"); + + return g_strdup_printf ("%s, %02d %s %d %s", + day_names[g_date_time_get_day_of_week (date_time) - 1], + g_date_time_get_day_of_month (date_time), + month_names[g_date_time_get_month (date_time) - 1], + g_date_time_get_year (date_time), + time_str); +#endif +} + +static GDateTime * +date_time_from_rfc7231 (const gchar *rfc7231_str) +{ +#if SOUP_CHECK_VERSION(3, 0, 0) + return soup_date_time_new_from_http_string (rfc7231_str); +#else + g_autoptr(SoupDate) soup_date = NULL; + g_autoptr(GTimeZone) tz = NULL; + + soup_date = soup_date_new_from_string (rfc7231_str); + if (soup_date == NULL) + return NULL; + + if (soup_date->utc) + tz = g_time_zone_new_utc (); + else + tz = g_time_zone_new_offset (soup_date->offset * 60); + + return g_date_time_new (tz, soup_date->year, soup_date->month, + soup_date->day, soup_date->hour, + soup_date->minute, soup_date->second); +#endif +} + +typedef struct { + /* Input data. */ + gchar *uri; /* (not nullable) (owned) */ + GInputStream *input_stream; /* (nullable) (owned) */ + GOutputStream *output_stream; /* (nullable) (owned) */ + gsize buffer_size_bytes; + gchar *last_etag; /* (nullable) (owned) */ + GDateTime *last_modified_date; /* (nullable) (owned) */ + int io_priority; + GsDownloadProgressCallback progress_callback; /* (nullable) */ + gpointer progress_user_data; + + /* In-progress state. */ + SoupMessage *message; /* (nullable) (owned) */ + gboolean close_input_stream; + gboolean close_output_stream; + gboolean discard_output_stream; + gsize total_read_bytes; + gsize total_written_bytes; + gsize expected_stream_size_bytes; + GBytes *currently_unwritten_chunk; /* (nullable) (owned) */ + + /* Output data. */ + gchar *new_etag; /* (nullable) (owned) */ + GDateTime *new_last_modified_date; /* (nullable) (owned) */ + GError *error; /* (nullable) (owned) */ +} DownloadData; + +static void +download_data_free (DownloadData *data) +{ + g_assert (data->input_stream == NULL || g_input_stream_is_closed (data->input_stream)); + g_assert (data->output_stream == NULL || g_output_stream_is_closed (data->output_stream)); + + g_assert (data->currently_unwritten_chunk == NULL || data->error != NULL); + + g_clear_object (&data->input_stream); + g_clear_object (&data->output_stream); + + g_clear_pointer (&data->last_etag, g_free); + g_clear_pointer (&data->last_modified_date, g_date_time_unref); + g_clear_object (&data->message); + g_clear_pointer (&data->uri, g_free); + g_clear_pointer (&data->new_etag, g_free); + g_clear_pointer (&data->new_last_modified_date, g_date_time_unref); + g_clear_pointer (&data->currently_unwritten_chunk, g_bytes_unref); + g_clear_error (&data->error); + + g_free (data); +} + +G_DEFINE_AUTOPTR_CLEANUP_FUNC (DownloadData, download_data_free) + +static void open_input_stream_cb (GObject *source_object, + GAsyncResult *result, + gpointer user_data); +static void read_bytes_cb (GObject *source_object, + GAsyncResult *result, + gpointer user_data); +static void write_bytes_cb (GObject *source_object, + GAsyncResult *result, + gpointer user_data); +static void finish_download (GTask *task, + GError *error); +static void close_stream_cb (GObject *source_object, + GAsyncResult *result, + gpointer user_data); +static void download_progress (GTask *task); + +/** + * gs_download_stream_async: + * @soup_session: a #SoupSession + * @uri: (not nullable): the URI to download + * @output_stream: (not nullable): an output stream to write the download to + * @last_etag: (nullable): the last-known ETag of the URI, or %NULL if unknown + * @last_modified_date: (nullable): the last-known Last-Modified date of the + * URI, or %NULL if unknown + * @io_priority: I/O priority to download and write at + * @progress_callback: (nullable): callback to call with progress information + * @progress_user_data: (nullable) (closure progress_callback): data to pass + * to @progress_callback + * @cancellable: (nullable): a #GCancellable, or %NULL + * @callback: callback to call once the operation is complete + * @user_data: (closure callback): data to pass to @callback + * + * Download @uri and write it to @output_stream asynchronously. + * + * If @last_etag is non-%NULL or @last_modified_date is non-%NULL, they will be + * sent to the server, which may return a ‘not modified’ response. If so, + * @output_stream will not be written to, and will be closed with a cancelled + * close operation. This will ensure that the existing content of the output + * stream (if it’s a file, for example) will not be overwritten. + * + * Note that @last_etag must be the ETag value returned by the server last time + * the file was downloaded, not the local file ETag generated by GLib. + * + * If specified, @progress_callback will be called zero or more times until + * @callback is called, providing progress updates on the download. + * + * Since: 43 + */ +void +gs_download_stream_async (SoupSession *soup_session, + const gchar *uri, + GOutputStream *output_stream, + const gchar *last_etag, + GDateTime *last_modified_date, + int io_priority, + GsDownloadProgressCallback progress_callback, + gpointer progress_user_data, + GCancellable *cancellable, + GAsyncReadyCallback callback, + gpointer user_data) +{ + g_autoptr(GTask) task = NULL; + g_autoptr(GError) local_error = NULL; + g_autoptr(SoupMessage) msg = NULL; + DownloadData *data; + g_autoptr(DownloadData) data_owned = NULL; + + g_return_if_fail (SOUP_IS_SESSION (soup_session)); + g_return_if_fail (uri != NULL); + g_return_if_fail (G_IS_OUTPUT_STREAM (output_stream)); + g_return_if_fail (cancellable == NULL || G_IS_CANCELLABLE (cancellable)); + + task = g_task_new (soup_session, cancellable, callback, user_data); + g_task_set_source_tag (task, gs_download_stream_async); + + data = data_owned = g_new0 (DownloadData, 1); + data->uri = g_strdup (uri); + data->output_stream = g_object_ref (output_stream); + data->close_output_stream = TRUE; + data->buffer_size_bytes = 8192; /* arbitrarily chosen */ + data->io_priority = io_priority; + data->progress_callback = progress_callback; + data->progress_user_data = progress_user_data; + + g_task_set_task_data (task, g_steal_pointer (&data_owned), (GDestroyNotify) download_data_free); + + /* local */ + if (g_str_has_prefix (uri, "file://")) { + g_autoptr(GFile) local_file = g_file_new_for_path (uri + strlen ("file://")); + g_file_read_async (local_file, io_priority, cancellable, open_input_stream_cb, g_steal_pointer (&task)); + return; + } + + /* remote */ + g_debug ("Downloading %s to %s", uri, G_OBJECT_TYPE_NAME (output_stream)); + msg = soup_message_new (SOUP_METHOD_GET, uri); + if (msg == NULL) { + finish_download (task, + g_error_new (G_IO_ERROR, + G_IO_ERROR_INVALID_ARGUMENT, + "Failed to parse URI ‘%s’", uri)); + return; + } + + data->message = g_object_ref (msg); + + /* Caching support. Prefer ETags to modification dates, as the latter + * have problems with rapid updates and clock drift. */ + if (last_etag != NULL && *last_etag == '\0') + last_etag = NULL; + data->last_etag = g_strdup (last_etag); + + if (last_modified_date != NULL) + data->last_modified_date = g_date_time_ref (last_modified_date); + + if (last_etag != NULL) { +#if SOUP_CHECK_VERSION(3, 0, 0) + soup_message_headers_append (soup_message_get_request_headers (msg), "If-None-Match", last_etag); +#else + soup_message_headers_append (msg->request_headers, "If-None-Match", last_etag); +#endif + } else if (last_modified_date != NULL) { + g_autofree gchar *last_modified_date_str = date_time_to_rfc7231 (last_modified_date); +#if SOUP_CHECK_VERSION(3, 0, 0) + soup_message_headers_append (soup_message_get_request_headers (msg), "If-Modified-Since", last_modified_date_str); +#else + soup_message_headers_append (msg->request_headers, "If-Modified-Since", last_modified_date_str); +#endif + } + +#if SOUP_CHECK_VERSION(3, 0, 0) + soup_session_send_async (soup_session, msg, data->io_priority, cancellable, open_input_stream_cb, g_steal_pointer (&task)); +#else + soup_session_send_async (soup_session, msg, cancellable, open_input_stream_cb, g_steal_pointer (&task)); +#endif +} + +static void +open_input_stream_cb (GObject *source_object, + GAsyncResult *result, + gpointer user_data) +{ + g_autoptr(GTask) task = g_steal_pointer (&user_data); + DownloadData *data = g_task_get_task_data (task); + GCancellable *cancellable = g_task_get_cancellable (task); + g_autoptr(GInputStream) input_stream = NULL; + g_autoptr(GError) local_error = NULL; + + /* This function can be called as a result of either reading a local + * file, or sending an HTTP request, so @source_object’s type can vary. */ + if (G_IS_FILE (source_object)) { + GFile *local_file = G_FILE (source_object); + + /* Local file. */ + input_stream = G_INPUT_STREAM (g_file_read_finish (local_file, result, &local_error)); + + if (input_stream == NULL) { + g_prefix_error (&local_error, "Failed to read ‘%s’: ", + g_file_peek_path (local_file)); + finish_download (task, g_steal_pointer (&local_error)); + return; + } + + g_assert (data->input_stream == NULL); + data->input_stream = g_object_ref (input_stream); + data->close_input_stream = TRUE; + } else if (SOUP_IS_SESSION (source_object)) { + SoupSession *soup_session = SOUP_SESSION (source_object); + guint status_code; + const gchar *new_etag, *new_last_modified_str; + + /* HTTP request. */ +#if SOUP_CHECK_VERSION(3, 0, 0) + input_stream = soup_session_send_finish (soup_session, result, &local_error); + status_code = soup_message_get_status (data->message); +#else + input_stream = soup_session_send_finish (soup_session, result, &local_error); + status_code = data->message->status_code; +#endif + + if (input_stream != NULL) { + g_assert (data->input_stream == NULL); + data->input_stream = g_object_ref (input_stream); + data->close_input_stream = TRUE; + } + + if (status_code == SOUP_STATUS_NOT_MODIFIED) { + /* If the file has not been modified from the ETag or + * Last-Modified date we have, finish the download + * early. Ensure to close the output stream so that its + * existing content is *not* overwritten. + * + * Preserve the existing ETag. */ + data->discard_output_stream = TRUE; + data->new_etag = g_strdup (data->last_etag); + data->new_last_modified_date = (data->last_modified_date != NULL) ? g_date_time_ref (data->last_modified_date) : NULL; + finish_download (task, + g_error_new (GS_DOWNLOAD_ERROR, + GS_DOWNLOAD_ERROR_NOT_MODIFIED, + "Skipped downloading ‘%s’: %s", + data->uri, soup_status_get_phrase (status_code))); + return; + } else if (status_code != SOUP_STATUS_OK) { + g_autoptr(GString) str = g_string_new (NULL); + g_string_append (str, soup_status_get_phrase (status_code)); + + if (local_error != NULL) { + g_string_append (str, ": "); + g_string_append (str, local_error->message); + } + + finish_download (task, + g_error_new (G_IO_ERROR, + G_IO_ERROR_FAILED, + "Failed to download ‘%s’: %s", + data->uri, str->str)); + return; + } + + g_assert (input_stream != NULL); + + /* Get the expected download size. */ +#if SOUP_CHECK_VERSION(3, 0, 0) + data->expected_stream_size_bytes = soup_message_headers_get_content_length (soup_message_get_response_headers (data->message)); +#else + data->expected_stream_size_bytes = soup_message_headers_get_content_length (data->message->response_headers); +#endif + + /* Store the new ETag for later use. */ +#if SOUP_CHECK_VERSION(3, 0, 0) + new_etag = soup_message_headers_get_one (soup_message_get_response_headers (data->message), "ETag"); +#else + new_etag = soup_message_headers_get_one (data->message->response_headers, "ETag"); +#endif + if (new_etag != NULL && *new_etag == '\0') + new_etag = NULL; + data->new_etag = g_strdup (new_etag); + + /* Store the Last-Modified date for later use. */ +#if SOUP_CHECK_VERSION(3, 0, 0) + new_last_modified_str = soup_message_headers_get_one (soup_message_get_response_headers (data->message), "Last-Modified"); +#else + new_last_modified_str = soup_message_headers_get_one (data->message->response_headers, "Last-Modified"); +#endif + if (new_last_modified_str != NULL && *new_last_modified_str == '\0') + new_last_modified_str = NULL; + if (new_last_modified_str != NULL) + data->new_last_modified_date = date_time_from_rfc7231 (new_last_modified_str); + } else { + g_assert_not_reached (); + } + + /* Splice in an asynchronous loop. We unfortunately can’t use + * g_output_stream_splice_async() here, as it doesn’t provide a progress + * callback. The approach is the same though. */ + g_input_stream_read_bytes_async (input_stream, data->buffer_size_bytes, data->io_priority, + cancellable, read_bytes_cb, g_steal_pointer (&task)); +} + +static void +read_bytes_cb (GObject *source_object, + GAsyncResult *result, + gpointer user_data) +{ + GInputStream *input_stream = G_INPUT_STREAM (source_object); + g_autoptr(GTask) task = g_steal_pointer (&user_data); + DownloadData *data = g_task_get_task_data (task); + GCancellable *cancellable = g_task_get_cancellable (task); + g_autoptr(GBytes) bytes = NULL; + g_autoptr(GError) local_error = NULL; + + bytes = g_input_stream_read_bytes_finish (input_stream, result, &local_error); + + if (bytes == NULL) { + finish_download (task, g_steal_pointer (&local_error)); + return; + } + + /* Report progress. */ + data->total_read_bytes += g_bytes_get_size (bytes); + data->expected_stream_size_bytes = MAX (data->expected_stream_size_bytes, data->total_read_bytes); + download_progress (task); + + /* Write the downloaded data. */ + if (g_bytes_get_size (bytes) > 0) { + g_clear_pointer (&data->currently_unwritten_chunk, g_bytes_unref); + data->currently_unwritten_chunk = g_bytes_ref (bytes); + + g_output_stream_write_bytes_async (data->output_stream, bytes, data->io_priority, + cancellable, write_bytes_cb, g_steal_pointer (&task)); + } else { + finish_download (task, NULL); + } +} + +static void +write_bytes_cb (GObject *source_object, + GAsyncResult *result, + gpointer user_data) +{ + GOutputStream *output_stream = G_OUTPUT_STREAM (source_object); + g_autoptr(GTask) task = g_steal_pointer (&user_data); + DownloadData *data = g_task_get_task_data (task); + GCancellable *cancellable = g_task_get_cancellable (task); + gssize bytes_written_signed; + gsize bytes_written; + g_autoptr(GError) local_error = NULL; + + bytes_written_signed = g_output_stream_write_bytes_finish (output_stream, result, &local_error); + + if (bytes_written_signed < 0) { + finish_download (task, g_steal_pointer (&local_error)); + return; + } + + /* We know this is non-negative now. */ + bytes_written = (gsize) bytes_written_signed; + + /* Report progress. */ + data->total_written_bytes += bytes_written; + download_progress (task); + + g_assert (data->currently_unwritten_chunk != NULL); + + if (bytes_written < g_bytes_get_size (data->currently_unwritten_chunk)) { + /* Partial write; try again with the remaining bytes. */ + g_autoptr(GBytes) sub_bytes = g_bytes_new_from_bytes (data->currently_unwritten_chunk, bytes_written, g_bytes_get_size (data->currently_unwritten_chunk) - bytes_written); + g_assert (bytes_written > 0); + + g_clear_pointer (&data->currently_unwritten_chunk, g_bytes_unref); + data->currently_unwritten_chunk = g_bytes_ref (sub_bytes); + + g_output_stream_write_bytes_async (output_stream, sub_bytes, data->io_priority, + cancellable, write_bytes_cb, g_steal_pointer (&task)); + } else { + /* Full write succeeded. Start the next read. */ + g_clear_pointer (&data->currently_unwritten_chunk, g_bytes_unref); + + g_input_stream_read_bytes_async (data->input_stream, data->buffer_size_bytes, data->io_priority, + cancellable, read_bytes_cb, g_steal_pointer (&task)); + } +} + +static inline gboolean +is_not_modidifed_error (GError *error) +{ + return g_error_matches (error, GS_DOWNLOAD_ERROR, GS_DOWNLOAD_ERROR_NOT_MODIFIED); +} + +/* error is (transfer full) */ +static void +finish_download (GTask *task, + GError *error) +{ + DownloadData *data = g_task_get_task_data (task); + GCancellable *cancellable = g_task_get_cancellable (task); + + /* Final progress update. */ + if (error == NULL || is_not_modidifed_error (error)) { + data->expected_stream_size_bytes = data->total_read_bytes; + download_progress (task); + } + + /* Record the error from the operation, if set. */ + g_assert (data->error == NULL); + data->error = g_steal_pointer (&error); + + g_assert (!data->discard_output_stream || data->close_output_stream); + + if (data->close_output_stream) { + g_autoptr(GCancellable) output_cancellable = NULL; + + g_assert (data->output_stream != NULL); + + /* If there’s been a prior error, or we are aborting writing the + * output stream (perhaps because of a cache hit), close the + * output stream but cancel the close operation so that the old + * output file is not overwritten. */ + if ((data->error != NULL && !is_not_modidifed_error (data->error)) || data->discard_output_stream) { + output_cancellable = g_cancellable_new (); + g_cancellable_cancel (output_cancellable); + } else if (g_task_get_cancellable (task) != NULL) { + output_cancellable = g_object_ref (g_task_get_cancellable (task)); + } + + g_output_stream_close_async (data->output_stream, data->io_priority, output_cancellable, close_stream_cb, g_object_ref (task)); + } + + if (data->close_input_stream && data->input_stream != NULL) { + g_input_stream_close_async (data->input_stream, data->io_priority, cancellable, close_stream_cb, g_object_ref (task)); + } + + /* Check in case both streams are already closed. */ + close_stream_cb (NULL, NULL, g_object_ref (task)); +} + +static void +close_stream_cb (GObject *source_object, + GAsyncResult *result, + gpointer user_data) +{ + g_autoptr(GTask) task = g_steal_pointer (&user_data); + DownloadData *data = g_task_get_task_data (task); + g_autoptr(GError) local_error = NULL; + + if (G_IS_INPUT_STREAM (source_object)) { + /* Errors in closing the input stream are not fatal. */ + if (!g_input_stream_close_finish (G_INPUT_STREAM (source_object), + result, &local_error)) + g_debug ("Error closing input stream: %s", local_error->message); + g_clear_error (&local_error); + + data->close_input_stream = FALSE; + } else if (G_IS_OUTPUT_STREAM (source_object)) { + /* Errors in closing the output stream are fatal, but don’t + * overwrite errors set earlier in the operation. */ + if (!g_output_stream_close_finish (G_OUTPUT_STREAM (source_object), + result, &local_error)) { + /* If we are aborting writing the output stream (perhaps + * because of a cache hit), don’t report the error at + * all. */ + if (data->discard_output_stream && + g_error_matches (local_error, G_IO_ERROR, G_IO_ERROR_CANCELLED)) + g_clear_error (&local_error); + else if (data->error == NULL) + data->error = g_steal_pointer (&local_error); + else if (!g_error_matches (local_error, G_IO_ERROR, G_IO_ERROR_CANCELLED)) + g_debug ("Error closing output stream: %s", local_error->message); + } + g_clear_error (&local_error); + + data->close_output_stream = FALSE; + data->discard_output_stream = FALSE; + } else { + /* finish_download() calls this with a NULL source_object */ + } + + /* Still waiting for one of the streams to close? */ + if (data->close_input_stream || data->close_output_stream) + return; + + if (data->error != NULL) { + g_task_return_error (task, g_error_copy (data->error)); + } else { + g_task_return_boolean (task, TRUE); + } +} + +static void +download_progress (GTask *task) +{ + DownloadData *data = g_task_get_task_data (task); + + if (data->progress_callback != NULL) { + /* This should be guaranteed by the rest of the download code. */ + g_assert (data->expected_stream_size_bytes >= data->total_written_bytes); + + data->progress_callback (data->total_written_bytes, data->expected_stream_size_bytes, + data->progress_user_data); + } +} + +/** + * gs_download_stream_finish: + * @soup_session: a #SoupSession + * @result: result of the asynchronous operation + * @new_etag_out: (out callee-allocates) (transfer full) (optional) (nullable): + * return location for the ETag of the downloaded file (which may be %NULL), + * or %NULL to ignore it + * @new_last_modified_date_out: (out callee-allocates) (transfer full) (optional) (nullable): + * return location for the new Last-Modified date of the downloaded file + * (which may be %NULL), or %NULL to ignore it + * @error: return location for a #GError + * + * Finish an asynchronous download operation started with + * gs_download_stream_async(). + * + * Returns: %TRUE on success, %FALSE otherwise + * Since: 43 + */ +gboolean +gs_download_stream_finish (SoupSession *soup_session, + GAsyncResult *result, + gchar **new_etag_out, + GDateTime **new_last_modified_date_out, + GError **error) +{ + DownloadData *data; + + g_return_val_if_fail (g_task_is_valid (result, soup_session), FALSE); + g_return_val_if_fail (g_task_get_source_tag (G_TASK (result)) == gs_download_stream_async, FALSE); + g_return_val_if_fail (error == NULL || *error == NULL, FALSE); + + data = g_task_get_task_data (G_TASK (result)); + + if (new_etag_out != NULL) + *new_etag_out = g_strdup (data->new_etag); + if (new_last_modified_date_out != NULL) + *new_last_modified_date_out = (data->new_last_modified_date != NULL) ? g_date_time_ref (data->new_last_modified_date) : NULL; + + return g_task_propagate_boolean (G_TASK (result), error); +} + +typedef struct { + /* Input data. */ + gchar *uri; /* (not nullable) (owned) */ + GFile *output_file; /* (not nullable) (owned) */ + int io_priority; + GsDownloadProgressCallback progress_callback; + gpointer progress_user_data; + + /* In-progress data. */ + gchar *last_etag; /* (nullable) (owned) */ + GDateTime *last_modified_date; /* (nullable) (owned) */ +} DownloadFileData; + +static void +download_file_data_free (DownloadFileData *data) +{ + g_free (data->uri); + g_clear_object (&data->output_file); + g_free (data->last_etag); + g_clear_pointer (&data->last_modified_date, g_date_time_unref); + g_free (data); +} + +G_DEFINE_AUTOPTR_CLEANUP_FUNC (DownloadFileData, download_file_data_free) + +static void download_replace_file_cb (GObject *source_object, + GAsyncResult *result, + gpointer user_data); +static void download_file_cb (GObject *source_object, + GAsyncResult *result, + gpointer user_data); + +/** + * gs_download_file_async: + * @soup_session: a #SoupSession + * @uri: (not nullable): the URI to download + * @output_file: (not nullable): an output file to write the download to + * @io_priority: I/O priority to download and write at + * @progress_callback: (nullable): callback to call with progress information + * @progress_user_data: (nullable) (closure progress_callback): data to pass + * to @progress_callback + * @cancellable: (nullable): a #GCancellable, or %NULL + * @callback: callback to call once the operation is complete + * @user_data: (closure callback): data to pass to @callback + * + * Download @uri and write it to @output_file asynchronously, overwriting the + * existing content of @output_file. + * + * The ETag and modification time of @output_file will be queried and, if known, + * used to skip the download if @output_file is already up to date. + * + * If specified, @progress_callback will be called zero or more times until + * @callback is called, providing progress updates on the download. + * + * Since: 42 + */ +void +gs_download_file_async (SoupSession *soup_session, + const gchar *uri, + GFile *output_file, + int io_priority, + GsDownloadProgressCallback progress_callback, + gpointer progress_user_data, + GCancellable *cancellable, + GAsyncReadyCallback callback, + gpointer user_data) +{ + g_autoptr(GTask) task = NULL; + DownloadFileData *data; + g_autoptr(DownloadFileData) data_owned = NULL; + g_autoptr(GFile) output_file_parent = NULL; + g_autoptr(GError) local_error = NULL; + + g_return_if_fail (SOUP_IS_SESSION (soup_session)); + g_return_if_fail (uri != NULL); + g_return_if_fail (G_IS_FILE (output_file)); + g_return_if_fail (cancellable == NULL || G_IS_CANCELLABLE (cancellable)); + + task = g_task_new (soup_session, cancellable, callback, user_data); + g_task_set_source_tag (task, gs_download_file_async); + + data = data_owned = g_new0 (DownloadFileData, 1); + data->uri = g_strdup (uri); + data->output_file = g_object_ref (output_file); + data->io_priority = io_priority; + data->progress_callback = progress_callback; + data->progress_user_data = progress_user_data; + g_task_set_task_data (task, g_steal_pointer (&data_owned), (GDestroyNotify) download_file_data_free); + + /* Create the destination file’s directory. + * FIXME: This should be made async; it hasn’t done for now as it’s + * likely to be fast. */ + output_file_parent = g_file_get_parent (output_file); + + if (output_file_parent != NULL && + !g_file_make_directory_with_parents (output_file_parent, cancellable, &local_error) && + !g_error_matches (local_error, G_IO_ERROR, G_IO_ERROR_EXISTS)) { + g_task_return_error (task, g_steal_pointer (&local_error)); + return; + } + + g_clear_error (&local_error); + + /* Query the old ETag and modification date if the file already exists. */ + data->last_etag = gs_utils_get_file_etag (output_file, &data->last_modified_date, cancellable); + + /* Create the output file. + * + * Note that `data->last_etag` is *not* passed in here, as the ETag from + * the server and the file modification ETag that GLib uses are + * different things. For g_file_replace_async(), GLib always uses an + * ETag it generates internally based on the file mtime (see + * _g_local_file_info_create_etag()), which will never match what the + * server returns in its ETag header. + * + * This is fine, as we are using the ETag to avoid an unnecessary HTTP + * download if possible. We don’t care about tracking changes to the + * file on disk. */ + g_file_replace_async (output_file, + NULL, /* ETag */ + FALSE, /* make_backup */ + G_FILE_CREATE_PRIVATE | G_FILE_CREATE_REPLACE_DESTINATION, + io_priority, + cancellable, + download_replace_file_cb, + g_steal_pointer (&task)); +} + +static void +download_replace_file_cb (GObject *source_object, + GAsyncResult *result, + gpointer user_data) +{ + GFile *output_file = G_FILE (source_object); + g_autoptr(GTask) task = g_steal_pointer (&user_data); + SoupSession *soup_session = g_task_get_source_object (task); + GCancellable *cancellable = g_task_get_cancellable (task); + DownloadFileData *data = g_task_get_task_data (task); + g_autoptr(GFileOutputStream) output_stream = NULL; + g_autoptr(GError) local_error = NULL; + + output_stream = g_file_replace_finish (output_file, result, &local_error); + + if (output_stream == NULL) { + g_task_return_error (task, g_steal_pointer (&local_error)); + return; + } + + /* Do the download. */ + gs_download_stream_async (soup_session, data->uri, G_OUTPUT_STREAM (output_stream), + data->last_etag, data->last_modified_date, data->io_priority, + data->progress_callback, data->progress_user_data, + cancellable, download_file_cb, g_steal_pointer (&task)); +} + +static void +download_file_cb (GObject *source_object, + GAsyncResult *result, + gpointer user_data) +{ + SoupSession *soup_session = SOUP_SESSION (source_object); + g_autoptr(GTask) task = g_steal_pointer (&user_data); + GCancellable *cancellable = g_task_get_cancellable (task); + DownloadFileData *data = g_task_get_task_data (task); + g_autofree gchar *new_etag = NULL; + g_autoptr(GError) local_error = NULL; + + if (!gs_download_stream_finish (soup_session, result, &new_etag, NULL, &local_error)) { + g_task_return_error (task, g_steal_pointer (&local_error)); + return; + } + + /* Update the stored HTTP ETag. + * + * Under the assumption that this code is only ever used for locally + * cached copies of remote files (i.e. the local copies are never + * modified except by downloading an updated version from the server), + * it’s safe to use the local file modification date for Last-Modified, + * and save having to update that explicitly. This is because the + * modification time of the local file equals when gnome-software last + * checked for updates to it — which is correct to send as the + * If-Modified-Since the next time gnome-software checks for updates to + * the file. */ + gs_utils_set_file_etag (data->output_file, new_etag, cancellable); + + g_task_return_boolean (task, TRUE); +} + +/** + * gs_download_file_finish: + * @soup_session: a #SoupSession + * @result: result of the asynchronous operation + * @error: return location for a #GError + * + * Finish an asynchronous download operation started with + * gs_download_file_async(). + * + * Returns: %TRUE on success, %FALSE otherwise + * Since: 42 + */ +gboolean +gs_download_file_finish (SoupSession *soup_session, + GAsyncResult *result, + GError **error) +{ + g_return_val_if_fail (g_task_is_valid (result, soup_session), FALSE); + g_return_val_if_fail (g_task_get_source_tag (G_TASK (result)) == gs_download_file_async, FALSE); + g_return_val_if_fail (error == NULL || *error == NULL, FALSE); + + return g_task_propagate_boolean (G_TASK (result), error); +} |