Completely inline the helper pure abstract __FlashStringHelper class (#7941)

* Remove __FlashStringHelper from ESP32, it's not needed - all the files using it are different from their ESP8266 counterparts anyway.

* Revert removal of class __FlashStringHelper forward for continued compatibility with external libs

* Improved fix, works for libs that return const __FlashStringHelper*

* Inline all wrappers using const __FlashStringHelper*.

cores/esp32/Print.cpp

@@ -74,11 +74,6 @@ size_t Print::printf(const char *format, ...)
     return len;
 }
 
-size_t Print::print(const __FlashStringHelper *ifsh)
-{
-    return print(reinterpret_cast<const char *>(ifsh));
-}
-
 size_t Print::print(const String &s)
 {
     return write(s.c_str(), s.length());
@@ -152,13 +147,6 @@ size_t Print::print(double n, int digits)
     return printFloat(n, digits);
 }
 
-size_t Print::println(const __FlashStringHelper *ifsh)
-{
-    size_t n = print(ifsh);
-    n += println();
-    return n;
-}
-
 size_t Print::print(const Printable& x)
 {
     return x.printTo(*this);

cores/esp32/Print.h

@@ -78,7 +78,7 @@ public:
     // default to zero, meaning "a single write may block"
     // should be overriden by subclasses with buffering
     virtual int availableForWrite() { return 0; }
-    size_t print(const __FlashStringHelper *);
+    size_t print(const __FlashStringHelper *ifsh) { return print(reinterpret_cast<const char *>(ifsh)); }
     size_t print(const String &);
     size_t print(const char[]);
     size_t print(char);
@@ -93,7 +93,7 @@ public:
     size_t print(const Printable&);
     size_t print(struct tm * timeinfo, const char * format = NULL);
 
-    size_t println(const __FlashStringHelper *);
+    size_t println(const __FlashStringHelper *ifsh) { return println(reinterpret_cast<const char *>(ifsh)); }
     size_t println(const String &s);
     size_t println(const char[]);
     size_t println(char);

cores/esp32/WString.cpp

@@ -47,11 +47,6 @@ String::String(const String &value) {
     *this = value;
 }
 
-String::String(const __FlashStringHelper *pstr) {
-    init();
-    *this = pstr; // see operator =
-}
-
 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 String::String(String &&rval) {
     init();
@@ -235,16 +230,6 @@ String & String::copy(const char *cstr, unsigned int length) {
     return *this;
 }
 
-String & String::copy(const __FlashStringHelper *pstr, unsigned int length) {
-    if (!reserve(length)) {
-        invalidate();
-        return *this;
-    }
-    memcpy_P(wbuffer(), (PGM_P)pstr, length + 1); // We know wbuffer() cannot ever be in PROGMEM, so memcpy safe here
-    setLen(length);
-    return *this;
-}
-
 #ifdef __GXX_EXPERIMENTAL_CXX0X__
 void String::move(String &rhs) {
     if(buffer()) {
@@ -308,15 +293,6 @@ String & String::operator =(const char *cstr) {
     return *this;
 }
 
-String & String::operator =(const __FlashStringHelper *pstr) {
-    if(pstr)
-        copy(pstr, strlen_P((PGM_P)pstr));
-    else
-        invalidate();
-
-    return *this;
-}
-
 /*********************************************/
 /*  concat                                   */
 /*********************************************/
@@ -424,20 +400,6 @@ bool String::concat(double num) {
     return concat(string, strlen(string));
 }
 
-bool String::concat(const __FlashStringHelper * str) {
-    if (!str)
-        return false;
-    int length = strlen_P((PGM_P)str);
-    if (length == 0)
-        return true;
-    unsigned int newlen = len() + length;
-    if (!reserve(newlen))
-        return false;
-    memcpy_P(wbuffer() + len(), (PGM_P)str, length + 1);
-    setLen(newlen);
-    return true;
-}
-
 /*********************************************/
 /*  Concatenate                              */
 /*********************************************/
@@ -526,14 +488,6 @@ StringSumHelper & operator +(const StringSumHelper &lhs, unsigned long long num)
     return a;
 }
 
-StringSumHelper & operator + (const StringSumHelper &lhs, const __FlashStringHelper *rhs)
-{
-    StringSumHelper &a = const_cast<StringSumHelper&>(lhs);
-    if (!a.concat(rhs))
-        a.invalidate();
-    return a;
-}
-
 /*********************************************/
 /*  Comparison                               */
 /*********************************************/

cores/esp32/WString.h

@@ -31,11 +31,11 @@
 #include <ctype.h>
 
 
-// an abstract class used as a means to proide a unique pointer type
-// but really has no body
+// A pure abstract class forward used as a means to proide a unique pointer type
+// but really is never defined.
 class __FlashStringHelper;
-#define FPSTR(pstr_pointer) (reinterpret_cast<const __FlashStringHelper *>(pstr_pointer))
-#define F(string_literal) (FPSTR(PSTR(string_literal)))
+#define FPSTR(pstr_pointer) (pstr_pointer)
+#define F(string_literal) (string_literal)
 
 // An inherited class for holding the result of a concatenation.  These
 // result objects are assumed to be writable by subsequent concatenations.
@@ -59,10 +59,10 @@ class String {
         String(const char *cstr = "");
         String(const char *cstr, unsigned int length);
 #ifdef __GXX_EXPERIMENTAL_CXX0X__
-        String(const uint8_t *cstr, unsigned int length) : String((const char*)cstr, length) {}
+        String(const uint8_t *cstr, unsigned int length) : String(reinterpret_cast<const char*>(cstr), length) {}
 #endif
         String(const String &str);
-        String(const __FlashStringHelper *str);
+        String(const __FlashStringHelper *str) : String(reinterpret_cast<const char*>(str)) {}
 #ifdef __GXX_EXPERIMENTAL_CXX0X__
         String(String &&rval);
         String(StringSumHelper &&rval);
@@ -103,7 +103,7 @@ class String {
         // marked as invalid ("if (s)" will be false).
         String & operator =(const String &rhs);
         String & operator =(const char *cstr);
-        String & operator = (const __FlashStringHelper *str);
+        String & operator = (const __FlashStringHelper *str) {return *this = reinterpret_cast<const char*>(str);}
 #ifdef __GXX_EXPERIMENTAL_CXX0X__
         String & operator =(String &&rval);
         String & operator =(StringSumHelper &&rval);
@@ -117,7 +117,7 @@ class String {
         bool concat(const String &str);
         bool concat(const char *cstr);
         bool concat(const char *cstr, unsigned int length);
-        bool concat(const uint8_t *cstr, unsigned int length) {return concat((const char*)cstr, length);}
+        bool concat(const uint8_t *cstr, unsigned int length) {return concat(reinterpret_cast<const char*>(cstr), length);}
         bool concat(char c);
         bool concat(unsigned char c);
         bool concat(int num);
@@ -128,7 +128,7 @@ class String {
         bool concat(double num);
         bool concat(long long num);
         bool concat(unsigned long long num);
-        bool concat(const __FlashStringHelper * str);
+        bool concat(const __FlashStringHelper * str) {return concat(reinterpret_cast<const char*>(str));}
 
         // if there's not enough memory for the concatenated value, the string
         // will be left unchanged (but this isn't signalled in any way)
@@ -180,10 +180,7 @@ class String {
             concat(num);
             return (*this);
         }
-        String & operator += (const __FlashStringHelper *str){
-            concat(str);
-            return (*this);
-        }
+        String & operator += (const __FlashStringHelper *str) {return *this += reinterpret_cast<const char*>(str);}
 
         friend StringSumHelper & operator +(const StringSumHelper &lhs, const String &rhs);
         friend StringSumHelper & operator +(const StringSumHelper &lhs, const char *cstr);
@@ -195,7 +192,6 @@ class String {
         friend StringSumHelper & operator +(const StringSumHelper &lhs, unsigned long num);
         friend StringSumHelper & operator +(const StringSumHelper &lhs, float num);
         friend StringSumHelper & operator +(const StringSumHelper &lhs, double num);
-        friend StringSumHelper & operator +(const StringSumHelper &lhs, const __FlashStringHelper *rhs);
         friend StringSumHelper & operator +(const StringSumHelper &lhs, long long num);
         friend StringSumHelper & operator +(const StringSumHelper &lhs, unsigned long long num);
 
@@ -229,7 +225,7 @@ class String {
             return this->startsWith(String(prefix));
         }
         bool startsWith(const __FlashStringHelper *prefix) const {
-            return this->startsWith(String(prefix));
+            return this->startsWith(reinterpret_cast<const char*>(prefix));
         }
         bool startsWith(const String &prefix, unsigned int offset) const;
         bool endsWith(const String &suffix) const;
@@ -237,7 +233,7 @@ class String {
             return this->endsWith(String(suffix));
         }
         bool endsWith(const __FlashStringHelper * suffix) const {
-            return this->endsWith(String(suffix));
+            return this->endsWith(reinterpret_cast<const char*>(suffix));
         }
 
         // character access
@@ -276,16 +272,16 @@ class String {
             this->replace(String(find), replace);
         }
         void replace(const __FlashStringHelper *find, const String &replace) {
-            this->replace(String(find), replace);
+            this->replace(reinterpret_cast<const char*>(find), replace);
         }
         void replace(const char *find, const char *replace) {
             this->replace(String(find), String(replace));
         }
         void replace(const __FlashStringHelper *find, const char *replace) {
-            this->replace(String(find), String(replace));
+            this->replace(reinterpret_cast<const char*>(find), String(replace));
         }
         void replace(const __FlashStringHelper *find, const __FlashStringHelper *replace) {
-            this->replace(String(find), String(replace));
+            this->replace(reinterpret_cast<const char*>(find), reinterpret_cast<const char*>(replace));
         }
         void remove(unsigned int index);
         void remove(unsigned int index, unsigned int count);
@@ -340,7 +336,7 @@ class String {
         inline void setCapacity(int cap) { if (!isSSO()) ptr.cap = cap; }
         inline void setBuffer(char *buff) { if (!isSSO()) ptr.buff = buff; }
         // Buffer accessor functions
-        inline const char *buffer() const { return (const char *)(isSSO() ? sso.buff : ptr.buff); }
+        inline const char *buffer() const { return reinterpret_cast<const char *>(isSSO() ? sso.buff : ptr.buff); }
         inline char *wbuffer() const { return isSSO() ? const_cast<char *>(sso.buff) : ptr.buff; } // Writable version of buffer
 
     protected:
@@ -350,7 +346,9 @@ class String {
 
         // copy and move
         String & copy(const char *cstr, unsigned int length);
-        String & copy(const __FlashStringHelper *pstr, unsigned int length);
+        String & copy(const __FlashStringHelper *pstr, unsigned int length) {
+                return copy(reinterpret_cast<const char*>(pstr), length);
+        }
 #ifdef __GXX_EXPERIMENTAL_CXX0X__
         void move(String &rhs);
 #endif
@@ -396,6 +394,10 @@ class StringSumHelper: public String {
         }
 };
         
+inline StringSumHelper & operator +(const StringSumHelper &lhs, const __FlashStringHelper *rhs) {
+        return lhs + reinterpret_cast<const char*>(rhs);
+}
+
 extern const String emptyString;
 
 #endif  // __cplusplus

libraries/WebServer/src/Uri.h

@@ -12,7 +12,7 @@ class Uri {
     public:
         Uri(const char *uri) : _uri(uri) {}
         Uri(const String &uri) : _uri(uri) {}
-        Uri(const __FlashStringHelper *uri) : _uri(String(uri)) {} 
+        Uri(const __FlashStringHelper *uri) : _uri((const char *)uri) {} 
         virtual ~Uri() {}
 
         virtual Uri* clone() const {