freeze constants in order to avoid unexpected modifications

5 files changed, 20 insertions, 20 deletions

diff --git a/lib/plum/connection.rb b/lib/plum/connection.rb
index 0f38e47..e8dc1e8 100644
--- a/lib/plum/connection.rb
+++ b/lib/plum/connection.rb
@@ -6,7 +6,7 @@ module Plum
     include FlowControl
     include ConnectionUtils
 
-    CLIENT_CONNECTION_PREFACE = "PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n"
+    CLIENT_CONNECTION_PREFACE = "PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n".freeze
 
     DEFAULT_SETTINGS = {
       header_table_size:      4096,     # octets
@@ -15,7 +15,7 @@ module Plum
       initial_window_size:    65535,    # octets; <= 2 ** 31 - 1
       max_frame_size:         16384,    # octets; <= 2 ** 24 - 1
       max_header_list_size:   (1 << 32) - 1 # Fixnum
-    }
+    }.freeze
 
     attr_reader :hpack_encoder, :hpack_decoder
     attr_reader :local_settings, :remote_settings
diff --git a/lib/plum/errors.rb b/lib/plum/errors.rb
index bdf8695..44b711f 100644
--- a/lib/plum/errors.rb
+++ b/lib/plum/errors.rb
@@ -17,7 +17,7 @@ module Plum
       enhance_your_calm:   0x0b,
       inadequate_security: 0x0c,
       http_1_1_required:   0x0d
-    }
+    }.freeze
 
     attr_reader :http2_error_type
 
diff --git a/lib/plum/frame.rb b/lib/plum/frame.rb
index 887bc8b..6520247 100644
--- a/lib/plum/frame.rb
+++ b/lib/plum/frame.rb
@@ -16,37 +16,37 @@ module Plum
       goaway:         0x07,
       window_update:  0x08,
       continuation:   0x09
-    }
+    }.freeze
 
     FRAME_FLAGS = {
       data: {
         end_stream:   0x01,
         padded:       0x08
-      },
+      }.freeze,
       headers: {
         end_stream:   0x01,
         end_headers:  0x04,
         padded:       0x08,
         priority:     0x20
-      },
-      priority: {},
-      rst_stream: {},
+      }.freeze,
+      priority: {}.freeze,
+      rst_stream: {}.freeze,
       settings: {
         ack:          0x01
-      },
+      }.freeze,
       push_promise: {
         end_headers:  0x04,
         padded:       0x08
-      },
+      }.freeze,
       ping: {
         ack:          0x01
-      },
-      goaway: {},
-      window_update: {},
+      }.freeze,
+      goaway: {}.freeze,
+      window_update: {}.freeze,
       continuation: {
         end_headers:  0x04
-      }
-    }
+      }.freeze
+    }.freeze
 
     SETTINGS_TYPE = {
       header_table_size:      0x01,
@@ -55,7 +55,7 @@ module Plum
       initial_window_size:    0x04,
       max_frame_size:         0x05,
       max_header_list_size:   0x06
-    }
+    }.freeze
 
     # RFC7540: 4.1 Frame format
     # +-----------------------------------------------+
diff --git a/lib/plum/hpack/constants.rb b/lib/plum/hpack/constants.rb
index 5c09a38..1cd3b2b 100644
--- a/lib/plum/hpack/constants.rb
+++ b/lib/plum/hpack/constants.rb
@@ -64,7 +64,7 @@ module Plum
       ["vary"],
       ["via"],
       ["www-authenticate"],
-    ]
+    ].freeze
 
     HUFFMAN_TABLE = [
       "1111111111000",
@@ -324,8 +324,8 @@ module Plum
       "111111111111111111111110000",
       "11111111111111111111101110",
       "111111111111111111111111111111"
-    ]
+    ].freeze
     
-    HUFFMAN_TABLE_INVERSED = HUFFMAN_TABLE.each_with_index.to_h
+    HUFFMAN_TABLE_INVERSED = HUFFMAN_TABLE.each_with_index.to_h.freeze
   end
 end
diff --git a/lib/plum/https_connection.rb b/lib/plum/https_connection.rb
index 95f2837..82f2f5e 100644
--- a/lib/plum/https_connection.rb
+++ b/lib/plum/https_connection.rb
@@ -26,6 +26,6 @@ module Plum
       AECDH-NULL-SHA AECDH-RC4-SHA AECDH-DES-CBC3-SHA AECDH-AES128-SHA AECDH-AES256-SHA SRP-3DES-EDE-CBC-SHA SRP-RSA-3DES-EDE-CBC-SHA SRP-DSS-3DES-EDE-CBC-SHA SRP-AES-128-CBC-SHA SRP-RSA-AES-128-CBC-SHA
       SRP-DSS-AES-128-CBC-SHA SRP-AES-256-CBC-SHA SRP-RSA-AES-256-CBC-SHA SRP-DSS-AES-256-CBC-SHA ECDHE-ECDSA-AES128-SHA256 ECDHE-ECDSA-AES256-SHA384 ECDH-ECDSA-AES128-SHA256 ECDH-ECDSA-AES256-SHA384 ECDHE-RSA-AES128-SHA256 ECDHE-RSA-AES256-SHA384
       ECDH-RSA-AES128-SHA256 ECDH-RSA-AES256-SHA384 ECDH-ECDSA-AES128-GCM-SHA256 ECDH-ECDSA-AES256-GCM-SHA384 ECDH-RSA-AES128-GCM-SHA256 ECDH-RSA-AES256-GCM-SHA384
-    )
+    ).freeze
   end
 end