Rust refactoring

* Move Context, Error, and character classes to their own modules.
* Move host/port parsing and IP address validation to their
  own modules, and break the code up into different functions
  to process their state machines.

1 files changed, 131 insertions, 0 deletions

diff --git a/src/character_classes.rs b/src/character_classes.rs
new file mode 100644
index 0000000..4b13f01
--- /dev/null
+++ b/src/character_classes.rs
@@ -0,0 +1,131 @@
+#![warn(clippy::pedantic)]
+
+use once_cell::sync::Lazy;
+use std::collections::HashSet;
+
+// This is the character set containing just the alphabetic characters
+// from the ASCII character set.
+pub static ALPHA: Lazy<HashSet<char>> = Lazy::new(||
+    ('a'..='z')
+    .chain('A'..='Z')
+    .collect()
+);
+
+// This is the character set containing just numbers.
+pub static DIGIT: Lazy<HashSet<char>> = Lazy::new(||
+    ('0'..='9')
+    .collect()
+);
+
+// This is the character set containing just the characters allowed
+// in a hexadecimal digit.
+pub static HEXDIG: Lazy<HashSet<char>> = Lazy::new(||
+    ('0'..='9')
+    .chain('A'..='F')
+    .chain('a'..='f')
+    .collect()
+);
+
+// This is the character set corresponds to the "unreserved" syntax
+// specified in RFC 3986 (https://tools.ietf.org/html/rfc3986).
+pub static UNRESERVED: Lazy<HashSet<char>> = Lazy::new(||
+    ALPHA.iter()
+    .chain(DIGIT.iter())
+    .chain(['-', '.', '_', '~'].iter())
+    .copied()
+    .collect()
+);
+
+// This is the character set corresponds to the "sub-delims" syntax
+// specified in RFC 3986 (https://tools.ietf.org/html/rfc3986).
+pub static SUB_DELIMS: Lazy<HashSet<char>> = Lazy::new(||
+    [
+        '!', '$', '&', '\'', '(', ')',
+        '*', '+', ',', ';', '='
+    ]
+    .iter()
+    .copied()
+    .collect()
+);
+
+// This is the character set corresponds to the second part
+// of the "scheme" syntax
+// specified in RFC 3986 (https://tools.ietf.org/html/rfc3986).
+pub static SCHEME_NOT_FIRST: Lazy<HashSet<char>> = Lazy::new(||
+    ALPHA.iter()
+    .chain(DIGIT.iter())
+    .chain(['+', '-', '.'].iter())
+    .copied()
+    .collect()
+);
+
+// This is the character set corresponds to the "pchar" syntax
+// specified in RFC 3986 (https://tools.ietf.org/html/rfc3986),
+// leaving out "pct-encoded".
+pub static PCHAR_NOT_PCT_ENCODED: Lazy<HashSet<char>> = Lazy::new(||
+    UNRESERVED.iter()
+    .chain(SUB_DELIMS.iter())
+    .chain([':', '@'].iter())
+    .copied()
+    .collect()
+);
+
+// This is the character set corresponds to the "query" syntax
+// and the "fragment" syntax
+// specified in RFC 3986 (https://tools.ietf.org/html/rfc3986),
+// leaving out "pct-encoded".
+pub static QUERY_OR_FRAGMENT_NOT_PCT_ENCODED: Lazy<HashSet<char>> = Lazy::new(||
+    PCHAR_NOT_PCT_ENCODED.iter()
+    .chain(['/', '?'].iter())
+    .copied()
+    .collect()
+);
+
+// This is the character set almost corresponds to the "query" syntax
+// specified in RFC 3986 (https://tools.ietf.org/html/rfc3986),
+// leaving out "pct-encoded", except that '+' is also excluded, because
+// for some web services (e.g. AWS S3) a '+' is treated as
+// synonymous with a space (' ') and thus gets misinterpreted.
+pub static QUERY_NOT_PCT_ENCODED_WITHOUT_PLUS: Lazy<HashSet<char>> = Lazy::new(||
+    UNRESERVED.iter()
+    .chain([
+        '!', '$', '&', '\'', '(', ')',
+        '*', ',', ';', '=',
+        ':', '@',
+        '/', '?'
+    ].iter())
+    .copied()
+    .collect()
+);
+
+// This is the character set corresponds to the "userinfo" syntax
+// specified in RFC 3986 (https://tools.ietf.org/html/rfc3986),
+// leaving out "pct-encoded".
+pub static USER_INFO_NOT_PCT_ENCODED: Lazy<HashSet<char>> = Lazy::new(||
+    UNRESERVED.iter()
+    .chain(SUB_DELIMS.iter())
+    .chain([':'].iter())
+    .copied()
+    .collect()
+);
+
+// This is the character set corresponds to the "reg-name" syntax
+// specified in RFC 3986 (https://tools.ietf.org/html/rfc3986),
+// leaving out "pct-encoded".
+pub static REG_NAME_NOT_PCT_ENCODED: Lazy<HashSet<char>> = Lazy::new(||
+    UNRESERVED.iter()
+    .chain(SUB_DELIMS.iter())
+    .copied()
+    .collect()
+);
+
+// This is the character set corresponds to the last part of
+// the "IPvFuture" syntax
+// specified in RFC 3986 (https://tools.ietf.org/html/rfc3986).
+pub static IPV_FUTURE_LAST_PART: Lazy<HashSet<char>> = Lazy::new(||
+    UNRESERVED.iter()
+    .chain(SUB_DELIMS.iter())
+    .chain([':'].iter())
+    .copied()
+    .collect()
+);