From ddc380dc076d5335a34c837f41c8e5163aef3c44 Mon Sep 17 00:00:00 2001
From: Richard Walters <rwalters@digitalstirling.com>
Date: Mon, 2 Jul 2018 00:17:22 -0700
Subject: Refactoring
* Replaced the more formal "state machine" used in URI
elements that may have percent-encoded characters, with
a simpler loop with a flag and a few conditional logic
paths.
* Extracted the parsing of the above types of elements into
a common method, DecodeElement.
* Kept DecodeQueryOrFragment around, in order to prevent
having to repeat the name of the allowed character set which
is common between query and fragment; however the function
is now just a very thin wrapper.
---
src/Uri.cpp | 140 +++++++++++++++++++-----------------------------------------
1 file changed, 45 insertions(+), 95 deletions(-)
diff --git a/src/Uri.cpp b/src/Uri.cpp
index bc16096..7580723 100644
--- a/src/Uri.cpp
+++ b/src/Uri.cpp
@@ -221,46 +221,50 @@ namespace {
}
/**
- * This method checks and decodes the given path segment.
+ * This method checks and decodes the given URI element.
+ * What we are calling a "URI element" is any part of the URI
+ * which is a sequence of characters that:
+ * - may be percent-encoded
+ * - if not percent-encoded, are in a restricted set of characters
*
- * @param[in,out] segment
- * On input, this is the path segment to check and decode.
- * On output, this is the decoded path segment.
+ * @param[in,out] element
+ * On input, this is the element to check and decode.
+ * On output, this is the decoded element.
+ *
+ * @param[in] allowedCharacters
+ * This is the set of characters that do not need to
+ * be percent-encoded.
*
* @return
- * An indication of whether or not the path segment
+ * An indication of whether or not the element
* passed all checks and was decoded successfully is returned.
*/
- bool DecodePathSegment(std::string& segment) {
- const auto originalSegment = std::move(segment);
- segment.clear();
- size_t decoderState = 0;
- int decodedCharacter = 0;
+ bool DecodeElement(
+ std::string& element,
+ const Uri::CharacterSet& allowedCharacters
+ ) {
+ const auto originalSegment = std::move(element);
+ element.clear();
+ bool decodingPec = false;
Uri::PercentEncodedCharacterDecoder pecDecoder;
for (const auto c: originalSegment) {
- switch(decoderState) {
- case 0: { // default
- if (c == '%') {
- pecDecoder = Uri::PercentEncodedCharacterDecoder();
- decoderState = 1;
- } else {
- if (PCHAR_NOT_PCT_ENCODED.Contains(c)) {
- segment.push_back(c);
- } else {
- return false;
- }
- }
- } break;
-
- case 1: { // % ...
- if (!pecDecoder.NextEncodedCharacter(c)) {
- return false;
- }
- if (pecDecoder.Done()) {
- decoderState = 0;
- segment.push_back((char)pecDecoder.GetDecodedCharacter());
- }
- } break;
+ if (decodingPec) {
+ if (!pecDecoder.NextEncodedCharacter(c)) {
+ return false;
+ }
+ if (pecDecoder.Done()) {
+ decodingPec = false;
+ element.push_back((char)pecDecoder.GetDecodedCharacter());
+ }
+ } else if (c == '%') {
+ decodingPec = true;
+ pecDecoder = Uri::PercentEncodedCharacterDecoder();
+ } else {
+ if (allowedCharacters.Contains(c)) {
+ element.push_back(c);
+ } else {
+ return false;
+ }
}
}
return true;
@@ -278,38 +282,10 @@ namespace {
* passed all checks and was decoded successfully is returned.
*/
bool DecodeQueryOrFragment(std::string& queryOrFragment) {
- const auto originalQueryOrFragment = std::move(queryOrFragment);
- queryOrFragment.clear();
- size_t decoderState = 0;
- int decodedCharacter = 0;
- Uri::PercentEncodedCharacterDecoder pecDecoder;
- for (const auto c: originalQueryOrFragment) {
- switch(decoderState) {
- case 0: { // default
- if (c == '%') {
- pecDecoder = Uri::PercentEncodedCharacterDecoder();
- decoderState = 1;
- } else {
- if (QUERY_OR_FRAGMENT_NOT_PCT_ENCODED.Contains(c)) {
- queryOrFragment.push_back(c);
- } else {
- return false;
- }
- }
- } break;
-
- case 1: { // % ...
- if (!pecDecoder.NextEncodedCharacter(c)) {
- return false;
- }
- if (pecDecoder.Done()) {
- decoderState = 0;
- queryOrFragment.push_back((char)pecDecoder.GetDecodedCharacter());
- }
- } break;
- }
- }
- return true;
+ return DecodeElement(
+ queryOrFragment,
+ QUERY_OR_FRAGMENT_NOT_PCT_ENCODED
+ );
}
}
@@ -402,7 +378,7 @@ namespace Uri {
}
}
for (auto& segment: path) {
- if (!DecodePathSegment(segment)) {
+ if (!DecodeElement(segment, PCHAR_NOT_PCT_ENCODED)) {
return false;
}
}
@@ -429,35 +405,9 @@ namespace Uri {
if (userInfoDelimiter == std::string::npos) {
hostPortString = authorityString;
} else {
- const auto userInfoEncoded = authorityString.substr(0, userInfoDelimiter);
- size_t decoderState = 0;
- int decodedCharacter = 0;
- PercentEncodedCharacterDecoder pecDecoder;
- for (const auto c: userInfoEncoded) {
- switch(decoderState) {
- case 0: { // default
- if (c == '%') {
- pecDecoder = PercentEncodedCharacterDecoder();
- decoderState = 1;
- } else {
- if (USER_INFO_NOT_PCT_ENCODED.Contains(c)) {
- userInfo.push_back(c);
- } else {
- return false;
- }
- }
- } break;
-
- case 1: { // % ...
- if (!pecDecoder.NextEncodedCharacter(c)) {
- return false;
- }
- if (pecDecoder.Done()) {
- decoderState = 0;
- userInfo.push_back((char)pecDecoder.GetDecodedCharacter());
- }
- } break;
- }
+ userInfo = authorityString.substr(0, userInfoDelimiter);
+ if (!DecodeElement(userInfo, USER_INFO_NOT_PCT_ENCODED)) {
+ return false;
}
hostPortString = authorityString.substr(userInfoDelimiter + 1);
}
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