Add new Pipeline convenience methods

ChangeLog

@@ -1,5 +1,10 @@
 2022-05-03  Jay Berkenbilt  <ejb@ql.org>
 
+        * Add new convenience methods to Pipeline: writeCStr and
+        writeString. Also add a limit << operator that takes C strings and
+        std::strings. Also add an overloaded version of write that takes
+        "char const*".
+
         * API change: Pipeline::write now takes "unsigned char const *"
         instead of "unsigned char*". Callers shouldn't have to change
         anything, though can stop using writable strings or

TODO

@@ -50,14 +50,6 @@ Need new pipelines:
 * Pl_OStream(std::ostream) with semantics like Pl_StdioFile
 * Pl_String to std::string with semantics like Pl_Buffer
 
-New Pipeline methods:
-* writeString(std::string const&)
-* writeCString(char*)
-* writeChars(char*, size_t)
-
-* Consider templated operator<< which could specialize for char* and
-  std::string and could use std::ostringstream otherwise
-
 See if I can change all output and error messages issued by the
 library, when context is available, to have a pipeline rather than a
 FILE* or std::ostream. This makes it possible for people to capture

include/qpdf/Pipeline.hh

@@ -71,6 +71,26 @@ class QPDF_DLL_CLASS Pipeline
     QPDF_DLL
     std::string getIdentifier() const;
 
+    // These are convenience methods for making it easier to write
+    // certain other types of data to pipelines without having to
+    // cast. The methods that take char const* expect null-terminated
+    // C strings and do not write the null terminators.
+    QPDF_DLL
+    void writeCStr(char const* cstr);
+    QPDF_DLL
+    void writeString(std::string const&);
+    // This allows *p << "x" << "y" but is not intended to be a
+    // general purpose << compatible with ostream and does not have
+    // local awareness or the ability to be "imbued" with properties.
+    QPDF_DLL
+    Pipeline& operator<<(char const* cstr);
+    QPDF_DLL
+    Pipeline& operator<<(std::string const&);
+
+    // Overloaded write to reduce casting
+    QPDF_DLL
+    void write(char const* data, size_t len);
+
   protected:
     QPDF_DLL
     Pipeline* getNext(bool allow_null = false);

libqpdf/Pipeline.cc

@@ -25,3 +25,35 @@ Pipeline::getIdentifier() const
 {
     return this->identifier;
 }
+
+void
+Pipeline::writeCStr(char const* cstr)
+{
+    this->write(cstr, strlen(cstr));
+}
+
+void
+Pipeline::writeString(std::string const& str)
+{
+    this->write(str.c_str(), str.length());
+}
+
+Pipeline&
+Pipeline::operator<<(char const* cstr)
+{
+    this->writeCStr(cstr);
+    return *this;
+}
+
+Pipeline&
+Pipeline::operator<<(std::string const& str)
+{
+    this->writeString(str);
+    return *this;
+}
+
+void
+Pipeline::write(char const* data, size_t len)
+{
+    this->write(reinterpret_cast<unsigned char const*>(data), len);
+}

manual/release-notes.rst

@@ -105,6 +105,18 @@ For a detailed list of changes, please see the file
       ``appendItemAndGet``, ``eraseItemAndGet``, ``replaceKeyAndGet``,
       and ``removeKeyAndGet`` return the newly added or removed object.
 
+    - Add new ``Pipeline`` methods to reduce the amount of casting that is
+      needed:
+
+      - ``write``: overloaded version that takes `char const*` in
+        addition to the one that takes `unsigned char const*`
+
+      - ``writeCstr``: writes a null-terminated C string
+
+      - ``writeString``: writes a std::string
+
+      - ``operator <<``: for null-terminated C strings and std::strings
+
   - Other changes
 
     - A new chapter on contributing to qpdf has been added to the