Add GZIP header processing to GZlibCompressor/GZlibDecompressor

Add GZlibCompressor:file-info property. If it contains a non-NULL
GFileInfo, and the compressor is in GZIP mode, the filename and
modification time from the file info are written to the GZIP header
in the output data.

Add GZlibDeompressor:file-info property. If the decompressor is in GZIP
mode, and the GZIP data contains a GZIP header, the filename and
modification time are read from it, stored in a GFileInfo, and the
file-info property is notified.

Bug #617691.

1 files changed, 126 insertions, 8 deletions

diff --git a/gio/gzlibdecompressor.c b/gio/gzlibdecompressor.c
index 7eeee79ed..f07261394 100644
--- a/gio/gzlibdecompressor.c
+++ b/gio/gzlibdecompressor.c
@@ -28,6 +28,7 @@
 #include <zlib.h>
 #include <string.h>
 
+#include "gfileinfo.h"
 #include "gioerror.h"
 #include "gioenums.h"
 #include "gioenumtypes.h"
@@ -36,7 +37,8 @@
 
 enum {
   PROP_0,
-  PROP_FORMAT
+  PROP_FORMAT,
+  PROP_FILE_INFO
 };
 
 /**
@@ -50,6 +52,12 @@ enum {
 
 static void g_zlib_decompressor_iface_init          (GConverterIface *iface);
 
+typedef struct {
+  gz_header gzheader;
+  char filename[257];
+  GFileInfo *file_info;
+} HeaderData;
+
 /**
  * GZlibDecompressor:
  *
@@ -61,8 +69,35 @@ struct _GZlibDecompressor
 
   GZlibCompressorFormat format;
   z_stream zstream;
+  HeaderData *header_data;
 };
 
+static void
+g_zlib_decompressor_set_gzheader (GZlibDecompressor *decompressor)
+{
+  if (decompressor->format != G_ZLIB_COMPRESSOR_FORMAT_GZIP)
+    return;
+
+  if (decompressor->header_data != NULL)
+    {
+      if (decompressor->header_data->file_info)
+        g_object_unref (decompressor->header_data->file_info);
+
+      memset (decompressor->header_data, 0, sizeof (HeaderData));
+    }
+  else
+    {
+      decompressor->header_data = g_new0 (HeaderData, 1);
+    }
+
+  decompressor->header_data->gzheader.name = (Bytef*) &decompressor->header_data->filename;
+  /* We keep one byte to guarantee the string is 0-terminated */
+  decompressor->header_data->gzheader.name_max = 256;
+
+  if (inflateGetHeader (&decompressor->zstream, &decompressor->header_data->gzheader) != Z_OK)
+    g_warning ("unexpected zlib error: %s\n", decompressor->zstream.msg);
+}
+
 G_DEFINE_TYPE_WITH_CODE (GZlibDecompressor, g_zlib_decompressor, G_TYPE_OBJECT,
 			 G_IMPLEMENT_INTERFACE (G_TYPE_CONVERTER,
 						g_zlib_decompressor_iface_init))
@@ -76,6 +111,13 @@ g_zlib_decompressor_finalize (GObject *object)
 
   inflateEnd (&decompressor->zstream);
 
+  if (decompressor->header_data != NULL)
+    {
+      if (decompressor->header_data->file_info)
+        g_object_unref (decompressor->header_data->file_info);
+      g_free (decompressor->header_data);
+    }
+
   G_OBJECT_CLASS (g_zlib_decompressor_parent_class)->finalize (object);
 }
 
@@ -119,6 +161,13 @@ g_zlib_decompressor_get_property (GObject    *object,
       g_value_set_enum (value, decompressor->format);
       break;
 
+    case PROP_FILE_INFO:
+      if (decompressor->header_data)
+        g_value_set_object (value, decompressor->header_data->file_info);
+      else
+        g_value_set_object (value, NULL);
+      break;
+
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
@@ -156,6 +205,8 @@ g_zlib_decompressor_constructed (GObject *object)
 
   if (res != Z_OK)
     g_warning ("unexpected zlib error: %s\n", decompressor->zstream.msg);
+
+  g_zlib_decompressor_set_gzheader (decompressor);
 }
 
 static void
@@ -177,6 +228,25 @@ g_zlib_decompressor_class_init (GZlibDecompressorClass *klass)
 						      G_ZLIB_COMPRESSOR_FORMAT_ZLIB,
 						      G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY |
 						      G_PARAM_STATIC_STRINGS));
+
+  /**
+   * GZlibDecompressor:file-info:
+   *
+   * A #GFileInfo containing the information found in the GZIP header
+   * of the data stream processed, or %NULL if the header was not yet
+   * fully processed, is not present at all, or the compressor's
+   * #GZlibDecompressor:format property is not %G_ZLIB_COMPRESSOR_FORMAT_GZIP.
+   *
+   * Since: 2.26
+   */
+  g_object_class_install_property (gobject_class,
+                                   PROP_FILE_INFO,
+                                   g_param_spec_object ("file-info",
+                                                       P_("file info"),
+                                                       P_("File info"),
+                                                       G_TYPE_FILE_INFO,
+                                                       G_PARAM_READABLE |
+                                                       G_PARAM_STATIC_STRINGS));
 }
 
 /**
@@ -201,6 +271,31 @@ g_zlib_decompressor_new (GZlibCompressorFormat format)
   return decompressor;
 }
 
+/**
+ * g_zlib_decompressor_get_file_info:
+ * @decompressor: a #GZlibDecompressor
+ *
+ * Retrieves the #GFileInfo constructed from the GZIP header data
+ * of compressed data processed by @compressor, or %NULL if @decompressor's
+ * #GZlibDecompressor:format property is not %G_ZLIB_COMPRESSOR_FORMAT_GZIP,
+ * or the header data was not fully processed yet, or it not present in the
+ * data stream at all.
+ *
+ * Returns: (transfer none): a #GFileInfo, or %NULL
+ *
+ * Since: 2.26
+ */
+GFileInfo *
+g_zlib_decompressor_get_file_info (GZlibDecompressor *decompressor)
+{
+  g_return_val_if_fail (G_IS_ZLIB_DECOMPRESSOR (decompressor), NULL);
+
+  if (decompressor->header_data)
+    return decompressor->header_data->file_info;
+
+  return NULL;
+}
+
 static void
 g_zlib_decompressor_reset (GConverter *converter)
 {
@@ -210,6 +305,8 @@ g_zlib_decompressor_reset (GConverter *converter)
   res = inflateReset (&decompressor->zstream);
   if (res != Z_OK)
     g_warning ("unexpected zlib error: %s\n", decompressor->zstream.msg);
+
+  g_zlib_decompressor_set_gzheader (decompressor);
 }
 
 static GConverterResult
@@ -271,17 +368,38 @@ g_zlib_decompressor_convert (GConverter *converter,
 	return G_CONVERTER_ERROR;
       }
 
-  if (res == Z_OK || res == Z_STREAM_END)
+  g_assert (res == Z_OK || res == Z_STREAM_END);
+
+  *bytes_read = inbuf_size - decompressor->zstream.avail_in;
+  *bytes_written = outbuf_size - decompressor->zstream.avail_out;
+
+  if (decompressor->header_data != NULL &&
+      decompressor->header_data->gzheader.done == 1)
     {
-      *bytes_read = inbuf_size - decompressor->zstream.avail_in;
-      *bytes_written = outbuf_size - decompressor->zstream.avail_out;
+      HeaderData *data = decompressor->header_data;
+
+      /* So we don't notify again */
+      data->gzheader.done = 2;
+
+      data->file_info = g_file_info_new ();
+      g_file_info_set_attribute_uint64 (data->file_info,
+                                        G_FILE_ATTRIBUTE_TIME_MODIFIED,
+                                        data->gzheader.time);
+      g_file_info_set_attribute_uint32 (data->file_info,
+                                        G_FILE_ATTRIBUTE_TIME_MODIFIED_USEC,
+                                        0);
+
+      if (data->filename[0] != '\0')
+        g_file_info_set_attribute_byte_string (data->file_info,
+                                               G_FILE_ATTRIBUTE_STANDARD_NAME,
+                                               data->filename);
 
-      if (res == Z_STREAM_END)
-	return G_CONVERTER_FINISHED;
-      return G_CONVERTER_CONVERTED;
+      g_object_notify (G_OBJECT (decompressor), "file-info");
     }
 
-  g_assert_not_reached ();
+  if (res == Z_STREAM_END)
+    return G_CONVERTER_FINISHED;
+  return G_CONVERTER_CONVERTED;
 }
 
 static void