create SAL_RETURNS_NONNULL annotation

and apply it to some methods in OString and OUString

Change-Id: I30e91f961b6d310799d3641f68b7ed54b3080f3a
Reviewed-on: https://gerrit.libreoffice.org/38020
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

5 files changed, 22 insertions, 6 deletions

diff --git a/include/rtl/strbuf.hxx b/include/rtl/strbuf.hxx
index 791eb142f9dc..eb5d4f738568 100644
--- a/include/rtl/strbuf.hxx
+++ b/include/rtl/strbuf.hxx
@@ -441,7 +441,7 @@ public:
     /**
         Return a null terminated character array.
      */
-    const sal_Char* getStr() const { return pData->buffer; }
+    const sal_Char* getStr() const SAL_RETURNS_NONNULL { return pData->buffer; }
 
     /**
       Access to individual characters.
@@ -709,7 +709,7 @@ public:
 
        @since LibreOffice 4.4
     */
-    char * appendUninitialized(sal_Int32 length) {
+    char * appendUninitialized(sal_Int32 length) SAL_RETURNS_NONNULL {
         sal_Int32 n = getLength();
         rtl_stringbuffer_insert(&pData, &nCapacity, n, NULL, length);
         return pData->buffer + n;
diff --git a/include/rtl/string.hxx b/include/rtl/string.hxx
index 37876983cd1b..2753713fc66f 100644
--- a/include/rtl/string.hxx
+++ b/include/rtl/string.hxx
@@ -432,7 +432,7 @@ public:
       @return a pointer to a null-terminated byte string representing the
       characters of this string object.
     */
-    const sal_Char * getStr() const { return pData->buffer; }
+    const sal_Char * getStr() const SAL_RETURNS_NONNULL { return pData->buffer; }
 
     /**
       Access to individual characters.
diff --git a/include/rtl/ustrbuf.hxx b/include/rtl/ustrbuf.hxx
index 04ba896b9b48..9dbc2621a7ae 100644
--- a/include/rtl/ustrbuf.hxx
+++ b/include/rtl/ustrbuf.hxx
@@ -474,7 +474,7 @@ public:
     /**
         Return a null terminated unicode character array.
      */
-    const sal_Unicode*  getStr() const { return pData->buffer; }
+    const sal_Unicode*  getStr() const SAL_RETURNS_NONNULL { return pData->buffer; }
 
     /**
       Access to individual characters.
@@ -885,7 +885,7 @@ public:
 
        @since LibreOffice 4.4
     */
-    sal_Unicode * appendUninitialized(sal_Int32 length) {
+    sal_Unicode * appendUninitialized(sal_Int32 length) SAL_RETURNS_NONNULL {
         sal_Int32 n = getLength();
         rtl_uStringbuffer_insert(&pData, &nCapacity, n, NULL, length);
         return pData->buffer + n;
diff --git a/include/rtl/ustring.hxx b/include/rtl/ustring.hxx
index 50f3be69bbbd..8b1cd3a1404f 100644
--- a/include/rtl/ustring.hxx
+++ b/include/rtl/ustring.hxx
@@ -662,7 +662,7 @@ public:
 
       @return   a pointer to the Unicode characters buffer for this object.
     */
-    const sal_Unicode * getStr() const { return pData->buffer; }
+    const sal_Unicode * getStr() const SAL_RETURNS_NONNULL { return pData->buffer; }
 
     /**
       Access to individual characters.
diff --git a/include/sal/types.h b/include/sal/types.h
index 30939f130281..b6d6730e88a5 100644
--- a/include/sal/types.h
+++ b/include/sal/types.h
@@ -687,6 +687,22 @@ inline char16_t const * SAL_U(wchar_t const * p)
 /// @endcond
 #endif
 
+
+/** Indicate where function/methods that return a pointer always
+    return a non-nullptr value.
+
+    Note that MSVC supports this feature via it's SAL _Ret_notnull_
+    annotation, but since it's in a completely different place on
+    the function declaration, it's a little hard to support both.
+
+    @since LibreOffice 5.5
+*/
+#if (defined __GNUC__ && __GNUC__ > 4) || defined __clang__
+#define SAL_RETURNS_NONNULL  __attribute__((returns_nonnull))
+#else
+#define SAL_RETURNS_NONNULL
+#endif
+
 #endif // INCLUDED_SAL_TYPES_H
 
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