Add QUtil::pipe_file and QUtil::file_provider

ChangeLog

@@ -1,3 +1,8 @@
+2021-02-07  Jay Berkenbilt  <ejb@ql.org>
+
+	* Add new functions QUtil::pipe_file and QUtil::file_provider for
+	sending the contents of a file through a pipeline as binary data.
+
 2021-02-04  Jay Berkenbilt  <ejb@ql.org>
 
 	* Add new option --pasword-file=file for reading the decryption

include/qpdf/QUtil.hh

@@ -34,6 +34,7 @@
 #include <time.h>
 
 class RandomDataProvider;
+class Pipeline;
 
 namespace QUtil
 {
@@ -119,6 +120,18 @@ namespace QUtil
     QPDF_DLL
     void rename_file(char const* oldname, char const* newname);
 
+    // Write the contents of filename as a binary file to the
+    // pipeline.
+    QPDF_DLL
+    void
+    pipe_file(char const* filename, Pipeline* p);
+
+    // Return a function that will send the contents of the given file
+    // through the given pipeline as binary data.
+    QPDF_DLL
+    std::function<void(Pipeline*)>
+    file_provider(std::string const& filename);
+
     QPDF_DLL
     char* copy_string(std::string const&);
 

libqpdf/QUtil.cc

@@ -7,6 +7,7 @@
 #include <qpdf/QPDFSystemError.hh>
 #include <qpdf/QTC.hh>
 #include <qpdf/QIntC.hh>
+#include <qpdf/Pipeline.hh>
 
 #include <cmath>
 #include <iomanip>
@@ -612,6 +613,35 @@ QUtil::rename_file(char const* oldname, char const* newname)
 #endif
 }
 
+void
+QUtil::pipe_file(char const* filename, Pipeline* p)
+{
+    // Exercised in test suite by testing file_provider.
+    FILE* f = safe_fopen(filename, "rb");
+    FileCloser fc(f);
+    size_t len = 0;
+    int constexpr size = 8192;
+    unsigned char buf[size];
+    while ((len = fread(buf, 1, size, f)) > 0)
+    {
+        p->write(buf, len);
+    }
+    p->finish();
+    if (ferror(f))
+    {
+        throw std::runtime_error(
+            std::string("failure reading file ") + filename);
+    }
+}
+
+std::function<void(Pipeline*)>
+QUtil::file_provider(std::string const& filename)
+{
+    return [filename](Pipeline* p) {
+        pipe_file(filename.c_str(), p);
+    };
+}
+
 char*
 QUtil::copy_string(std::string const& str)
 {
@@ -1018,6 +1048,7 @@ QUtil::read_file_into_memory(
     PointerHolder<char>& file_buf, size_t& size)
 {
     FILE* f = safe_fopen(filename, "rb");
+    FileCloser fc(f);
     fseek(f, 0, SEEK_END);
     size = QIntC::to_size(QUtil::tell(f));
     fseek(f, 0, SEEK_SET);
@@ -1048,7 +1079,6 @@ QUtil::read_file_into_memory(
                 uint_to_string(size));
         }
     }
-    fclose(f);
 }
 
 static bool read_char_from_FILE(char& ch, FILE* f)

libtests/qutil.cc

@@ -6,6 +6,7 @@
 #include <qpdf/QUtil.hh>
 #include <qpdf/PointerHolder.hh>
 #include <qpdf/QPDFSystemError.hh>
+#include <qpdf/Pl_Buffer.hh>
 #include <string.h>
 #include <limits.h>
 #include <assert.h>
@@ -483,6 +484,12 @@ void read_from_file_test()
     assert(memcmp(p, "This file is used for qutil testing.", 36) == 0);
     assert(p[59] == static_cast<char>(13));
     assert(memcmp(p + 24641, "very long.", 10) == 0);
+    Pl_Buffer b2("buffer");
+    // QUtil::file_provider also exercises QUtil::pipe_file
+    QUtil::file_provider("other-file")(&b2);
+    auto buf2 = b2.getBuffer();
+    assert(buf2->getSize() == size);
+    assert(memcmp(buf2->getBuffer(), p, size) == 0);
 }
 
 void assert_hex_encode(std::string const& input, std::string const& expected)

manual/qpdf-manual.xml

@@ -4964,6 +4964,13 @@ print "\n";
           read/write implementation of name and number trees.
          </para>
         </listitem>
+        <listitem>
+         <para>
+          Add new functions <function>QUtil::pipe_file</function> and
+          <function>QUtil::file_provider</function> for sending the
+          contents of a file through a pipeline as binary data.
+         </para>
+        </listitem>
        </itemizedlist>
       </listitem>
       <listitem>