Allow reading from InputSource and writing to Pipeline

Allowing users to subclass InputSource and Pipeline to read and write from/to arbitrary sources provides the maximum flexibility for users who want to read and write from other than files or memory.

Allow reading from InputSource and writing to Pipeline
Allowing users to subclass InputSource and Pipeline to read and write from/to arbitrary sources provides the maximum flexibility for users who want to read and write from other than files or memory.
Jay Berkenbilt
1 parent 8c99e4a6
Showing 8 changed files with 64 additions and 7 deletions
ChangeLog
include/qpdf/QPDF.hh
include/qpdf/QPDFWriter.hh
libqpdf/QPDF.cc
libqpdf/QPDFWriter.cc
qpdf/qtest/qpdf.test
qpdf/qtest/qpdf/custom-pipeline.pdf
qpdf/test_driver.cc
+2012-09-23  Jay Berkenbilt  <ejb@ql.org>
+
+	* Add public methods QPDF::processInputSource and
+	QPDFWriter::setOutputPipeline to allow users to read from custom
+	input sources and to write to custom pipelines.  This allows the
+	maximum flexibility in sources for reading and writing PDF files.
+
 2012-09-06  Jay Berkenbilt  <ejb@ql.org>
 	* 3.0.2: release
@@ -72,6 +72,13 @@ class QPDF
 			   char const* buf, size_t length,
 			   char const* password = 0);
+    // Parse a PDF file loaded from a custom InputSource.  If you have
+    // your own method of retrieving a PDF file, you can subclass
+    // InputSource and use this method.
+    QPDF_DLL
+    void processInputSource(PointerHolder<InputSource>,
+                            char const* password = 0);
+
     // Create a QPDF object for an empty PDF.  This PDF has no pages
     // or objects other than a minimal trailer, a document catalog,
     // and a /Pages tree containing zero pages.  Pages and other
@@ -95,6 +95,15 @@ class QPDFWriter
     QPDF_DLL
     Buffer* getBuffer();
+    // Supply your own pipeline object.  Output will be written to
+    // this pipeline, and QPDFWriter will call finish() on the
+    // pipeline.  It is the caller's responsibility to manage the
+    // memory for the pipeline.  The pipeline is never deleted by
+    // QPDFWriter, which makes it possible for you to call additional
+    // methods on the pipeline after the writing is finished.
+    QPDF_DLL
+    void setOutputPipeline(Pipeline*);
+
     // Setting Parameters
     // Set the value of object stream mode.  In disable mode, we never
@@ -138,9 +138,8 @@ void
 QPDF::processFile(char const* filename, char const* password)
 {
     FileInputSource* fi = new FileInputSource();
-    this->file = fi;
     fi->setFilename(filename);
-    parse(password);
+    processInputSource(fi, password);
 }
 void
@@ -148,9 +147,8 @@ QPDF::processFile(char const* description, FILE* filep,
                   bool close_file, char const* password)
 {
     FileInputSource* fi = new FileInputSource();
-    this->file = fi;
     fi->setFile(description, filep, close_file);
-    parse(password);
+    processInputSource(fi, password);
 }
 void
@@ -158,10 +156,18 @@ QPDF::processMemoryFile(char const* description,
 			char const* buf, size_t length,
 			char const* password)
 {
-    this->file =
+    processInputSource(
 	new BufferInputSource(description,
 			      new Buffer((unsigned char*)buf, length),
-			      true);
+			      true),
+        password);
+}
+
+void
+QPDF::processInputSource(PointerHolder<InputSource> source,
+                         char const* password)
+{
+    this->file = source;
     parse(password);
 }
@@ -135,6 +135,13 @@ QPDFWriter::getBuffer()
 }
 void
+QPDFWriter::setOutputPipeline(Pipeline* p)
+{
+    this->filename = "custom pipeline";
+    initializePipelineStack(p);
+}
+
+void
 QPDFWriter::setObjectStreamMode(qpdf_object_stream_e mode)
 {
     this->object_stream_mode = mode;
@@ -149,7 +149,7 @@ $td-&gt;runtest(&quot;remove page we don&#39;t have&quot;,
 	     $td->NORMALIZE_NEWLINES);
 # ----------
 $td->notify("--- Miscellaneous Tests ---");
-$n_tests += 53;
+$n_tests += 55;
 $td->runtest("qpdf version",
 	     {$td->COMMAND => "qpdf --version"},
@@ -403,6 +403,13 @@ $td-&gt;runtest(&quot;check output&quot;,
 $td->runtest("check output",
              {$td->FILE => "d.pdf"},
              {$td->FILE => "extra-header-lin-newline.pdf"});
+$td->runtest("output to custom pipeline",
+             {$td->COMMAND => "test_driver 33 minimal.pdf"},
+             {$td->STRING => "test 33 done\n", $td->EXIT_STATUS => 0},
+             $td->NORMALIZE_NEWLINES);
+$td->runtest("check output",
+             {$td->FILE => "a.pdf"},
+             {$td->FILE => "custom-pipeline.pdf"});
 show_ntests();
 # ----------
@@ -1112,6 +1112,20 @@ void runtest(int n, char const* filename1, char const* filename2)
             w.write();
         }
     }
+    else if (n == 33)
+    {
+        // Test writing to a custom pipeline
+        Pl_Buffer p("buffer");
+        QPDFWriter w(pdf);
+        w.setStaticID(true);
+        w.setOutputPipeline(&p);
+        w.write();
+        PointerHolder<Buffer> b = p.getBuffer();
+        FILE* f = QUtil::fopen_wrapper("open a.pdf",
+                                       fopen("a.pdf", "wb"));
+        fwrite(b->getBuffer(), b->getSize(), 1, f);
+        fclose(f);
+    }
     else
     {
 	throw std::runtime_error(std::string("invalid test ") +