Add a support for decompressing Zstandard-compressed YAML files

meson.build

@@ -12,7 +12,7 @@
 project(
   'modulemd',
   'c',
-version : '2.14.1',
+version : '2.15.0',
 default_options : ['buildtype=debugoptimized', 'c_std=c11', 'warning_level=1', 'b_asneeded=true'],
 license : 'MIT',
 meson_version : '>=0.55.0'

modulemd/include/modulemd-2.0/modulemd-compression.h

@@ -34,12 +34,14 @@ G_BEGIN_DECLS
  * @MODULEMD_COMPRESSION_TYPE_BZ2_COMPRESSION: bzip2 compression
  * @MODULEMD_COMPRESSION_TYPE_XZ_COMPRESSION: LZMA compression
  * @MODULEMD_COMPRESSION_TYPE_ZCK_COMPRESSION: zchunk compression
+ * @MODULEMD_COMPRESSION_TYPE_ZSTD_COMPRESSION: Zstandard compression; since 2.15
  * @MODULEMD_COMPRESSION_TYPE_SENTINEL: Enum list terminator
  *
  * Since: 2.8
  */
 typedef enum
 {
+  MODULEMD_COMPRESSION_TYPE_ZSTD_COMPRESSION = -3,
   MODULEMD_COMPRESSION_TYPE_DETECTION_FAILED = -2,
   MODULEMD_COMPRESSION_TYPE_UNKNOWN_COMPRESSION,
   MODULEMD_COMPRESSION_TYPE_NO_COMPRESSION,
@@ -54,7 +56,7 @@ typedef enum
 /**
  * modulemd_compression_type:
  * @name: (in): The name of the compression type. Valid options are:
- * "gz", "gzip", "bz2", "bzip2", "xz" and "zck".
+ * "gz", "gzip", "bz2", "bzip2", "xz", "zck", and "zstd".
  *
  * Returns: The #ModulemdCompressionTypeEnum value corresponding to the
  * provided string if available or

modulemd/modulemd-compression.c

@@ -63,6 +63,10 @@ modulemd_detect_compression (const gchar *filename, int fd, GError **error)
     {
       return MODULEMD_COMPRESSION_TYPE_XZ_COMPRESSION;
     }
+  if (g_str_has_suffix (filename, ".zst"))
+    {
+      return MODULEMD_COMPRESSION_TYPE_ZSTD_COMPRESSION;
+    }
   if (g_str_has_suffix (filename, ".yaml") ||
       g_str_has_suffix (filename, ".yml") ||
       g_str_has_suffix (filename, ".txt"))
@@ -71,7 +75,7 @@ modulemd_detect_compression (const gchar *filename, int fd, GError **error)
     }
 
   /* No known suffix? Inspect magic bytes in the content. */
-  unsigned char buffer[6]; /* gzip, bzip2 have a 4-byte header.
+  unsigned char buffer[6]; /* gzip, bzip2, zstd have a 4-byte header.
                                     xz has a 6-byte header. */
   size_t filled = 0;
   ssize_t retval = 0;
@@ -127,6 +131,14 @@ modulemd_detect_compression (const gchar *filename, int fd, GError **error)
       buffer[3] == 'X' && buffer[4] == 'Z' && buffer[5] == 0x00)
     /* The .xz File Format, Version 1.1.0 (2022-12-11). */
     return MODULEMD_COMPRESSION_TYPE_XZ_COMPRESSION;
+  if (/* Zstandard frame */
+      (buffer[0] == 0x28 && buffer[1] == 0xb5 && buffer[2] == 0x2f &&
+       buffer[3] == 0xfd) ||
+      /* Skippable frame */
+      ((buffer[0] & 0xf0) == 0x50 && buffer[1] == 0x2a && buffer[2] == 0x4d &&
+       buffer[3] == 0x18))
+    /* RFC 8878. */
+    return MODULEMD_COMPRESSION_TYPE_ZSTD_COMPRESSION;
 
   /* Fall back to no compression. YAML parser will error later on a binary
    * garbage. YAML 1.2.2 requires to support UTF-8, UTF-16, UTF-32, with and
@@ -162,6 +174,10 @@ modulemd_compression_type (const gchar *name)
     {
       type = MODULEMD_COMPRESSION_TYPE_ZCK_COMPRESSION;
     }
+  if (!g_strcmp0 (name, "zstd"))
+    {
+      type = MODULEMD_COMPRESSION_TYPE_ZSTD_COMPRESSION;
+    }
 
   return type;
 }
@@ -174,6 +190,7 @@ modulemd_compression_suffix (ModulemdCompressionTypeEnum comtype)
     case MODULEMD_COMPRESSION_TYPE_GZ_COMPRESSION: return ".gz";
     case MODULEMD_COMPRESSION_TYPE_BZ2_COMPRESSION: return ".bz2";
     case MODULEMD_COMPRESSION_TYPE_XZ_COMPRESSION: return ".xz";
+    case MODULEMD_COMPRESSION_TYPE_ZSTD_COMPRESSION: return ".zst";
     default: return NULL;
     }
 }
@@ -195,6 +212,8 @@ get_comtype_string (ModulemdCompressionTypeEnum comtype)
 
     case MODULEMD_COMPRESSION_TYPE_XZ_COMPRESSION: return "xzdio"; break;
 
+    case MODULEMD_COMPRESSION_TYPE_ZSTD_COMPRESSION: return "zstdio"; break;
+
     default:
       g_info ("Unknown compression type: %d", comtype);
       return NULL;

modulemd/tests/test-modulemd-compression.c

@@ -45,6 +45,10 @@ test_modulemd_compression_type (void)
                    ==,
                    MODULEMD_COMPRESSION_TYPE_XZ_COMPRESSION);
 
+  g_assert_cmpint (modulemd_compression_type ("zstd"),
+                   ==,
+                   MODULEMD_COMPRESSION_TYPE_ZSTD_COMPRESSION);
+
   g_assert_cmpint (modulemd_compression_type ("garbage"),
                    ==,
                    MODULEMD_COMPRESSION_TYPE_UNKNOWN_COMPRESSION);
@@ -78,6 +82,8 @@ test_modulemd_detect_compression (void)
       .type = MODULEMD_COMPRESSION_TYPE_GZ_COMPRESSION },
     { .filename = "xzipped.yaml.xz",
       .type = MODULEMD_COMPRESSION_TYPE_XZ_COMPRESSION },
+    { .filename = "zstded.yaml.zst",
+      .type = MODULEMD_COMPRESSION_TYPE_ZSTD_COMPRESSION },
     { .filename = "uncompressed.yaml",
       .type = MODULEMD_COMPRESSION_TYPE_NO_COMPRESSION },
     { .filename = "empty", .type = MODULEMD_COMPRESSION_TYPE_NO_COMPRESSION },
@@ -111,6 +117,8 @@ test_modulemd_detect_compression (void)
       .type = MODULEMD_COMPRESSION_TYPE_GZ_COMPRESSION },
     { .filename = "xzipped",
       .type = MODULEMD_COMPRESSION_TYPE_XZ_COMPRESSION },
+    { .filename = "zstded",
+      .type = MODULEMD_COMPRESSION_TYPE_ZSTD_COMPRESSION },
     { .filename = "uncompressed",
       .type = MODULEMD_COMPRESSION_TYPE_NO_COMPRESSION },
     { .filename = "empty", .type = MODULEMD_COMPRESSION_TYPE_NO_COMPRESSION },
@@ -152,6 +160,7 @@ test_modulemd_compression_suffix (void)
     { .type = MODULEMD_COMPRESSION_TYPE_GZ_COMPRESSION, .suffix = ".gz" },
     { .type = MODULEMD_COMPRESSION_TYPE_BZ2_COMPRESSION, .suffix = ".bz2" },
     { .type = MODULEMD_COMPRESSION_TYPE_XZ_COMPRESSION, .suffix = ".xz" },
+    { .type = MODULEMD_COMPRESSION_TYPE_ZSTD_COMPRESSION, .suffix = ".zst" },
     { .type = MODULEMD_COMPRESSION_TYPE_SENTINEL, .suffix = NULL }
   };
 
@@ -181,6 +190,7 @@ test_modulemd_get_rpmio_fmode (void)
     { .type = MODULEMD_COMPRESSION_TYPE_GZ_COMPRESSION, .suffix = "gzdio" },
     { .type = MODULEMD_COMPRESSION_TYPE_BZ2_COMPRESSION, .suffix = "bzdio" },
     { .type = MODULEMD_COMPRESSION_TYPE_XZ_COMPRESSION, .suffix = "xzdio" },
+    { .type = MODULEMD_COMPRESSION_TYPE_ZSTD_COMPRESSION, .suffix = "zstdio" },
     { .type = MODULEMD_COMPRESSION_TYPE_SENTINEL, .suffix = NULL }
   };