[squid-dev] [PATCH] SBuf const iterator fixes

[Amos Jeffries]

The SBufIterator is mostly actually a const iterator. But not quite.

The point of difference from const_iterator is the operator*() API which
is also different from the normal itertor API in that is returns a char
instead of a char& or const char &.

The attached patch fixes that API making the iterator equivalent to
const_iterator for the subset of iterator API that it does present.

This has side effects on the reverse iterator and SBuf begin/end
methods. Which are also const'ified.

There appears to be no built-time or unit test identified problems from
this change. IT passes the build farm QA easily.

Are there any objections to fast-tracking this merge? If not I hope to
apply this in the next day or two.

Amos
-------------- next part --------------
=== modified file 'src/SBuf.h'
--- src/SBuf.h	2016-01-01 00:12:18 +0000
+++ src/SBuf.h	2016-02-08 11:08:07 +0000
@@ -83,7 +83,7 @@
 class CharacterSet;
 class SBuf;
 
-/** Forward input iterator for SBufs
+/** Forward input const_iterator for SBufs
  *
  * Please note that any operation on the underlying SBuf may invalidate
  * all iterators over it, resulting in undefined behavior by them.
@@ -96,7 +96,7 @@
     bool operator==(const SBufIterator &s) const;
     bool operator!=(const SBufIterator &s) const;
 
-    char operator*() const { return *iter; }
+    const char &operator*() const { return *iter; }
     SBufIterator& operator++() { ++iter; return *this; }
 
 protected:
@@ -105,7 +105,7 @@
     const char *iter;
 };
 
-/** Reverse input iterator for SBufs
+/** Reverse input const_iterator for SBufs
  *
  * Please note that any operation on the underlying SBuf may invalidate
  * all iterators over it, resulting in undefined behavior by them.
@@ -115,7 +115,7 @@
     friend class SBuf;
 public:
     SBufReverseIterator& operator++() { --iter; return *this;}
-    char operator*() const { return *(iter-1); }
+    const char &operator*() const { return *(iter-1); }
 protected:
     SBufReverseIterator(const SBuf &s, size_type sz) : SBufIterator(s,sz) {}
 };
@@ -130,8 +130,8 @@
 {
 public:
     typedef MemBlob::size_type size_type;
-    typedef SBufIterator iterator;
-    typedef SBufReverseIterator reverse_iterator;
+    typedef SBufIterator const_iterator;
+    typedef SBufReverseIterator const_reverse_iterator;
     static const size_type npos = 0xffffffff; // max(uint32_t)
 
     /// Maximum size of a SBuf. By design it MUST be < MAX(size_type)/2. Currently 256Mb.
@@ -648,20 +648,20 @@
     /// std::string export function
     std::string toStdString() const { return std::string(buf(),length()); }
 
-    iterator begin() {
-        return iterator(*this, 0);
-    }
-
-    iterator end() {
-        return iterator(*this, length());
-    }
-
-    reverse_iterator rbegin() {
-        return reverse_iterator(*this, length());
-    }
-
-    reverse_iterator rend() {
-        return reverse_iterator(*this, 0);
+    const_iterator begin() const {
+        return const_iterator(*this, 0);
+    }
+
+    const_iterator end() const {
+        return const_iterator(*this, length());
+    }
+
+    const_reverse_iterator rbegin() const {
+        return const_reverse_iterator(*this, length());
+    }
+
+    const_reverse_iterator rend() const {
+        return const_reverse_iterator(*this, 0);
     }
 
     // TODO: possibly implement erase() similar to std::string's erase