ClosedFileInputSource: add method to keep file open

During periods of intensive operation on a specific file, this method
can reduce the overhead of repeated open/close operations.

1 files changed, 20 insertions, 1 deletions

diff --git a/libqpdf/ClosedFileInputSource.cc b/libqpdf/ClosedFileInputSource.cc
index ea79a840..63357886 100644
--- a/libqpdf/ClosedFileInputSource.cc
+++ b/libqpdf/ClosedFileInputSource.cc
@@ -4,7 +4,8 @@
 ClosedFileInputSource::Members::Members(char const* filename) :
     filename(filename),
     offset(0),
-    fis(0)
+    fis(0),
+    stay_open(false)
 {
 }
 
@@ -42,6 +43,10 @@ ClosedFileInputSource::after()
 {
     this->last_offset = this->m->fis->getLastOffset();
     this->m->offset = this->m->fis->tell();
+    if (this->m->stay_open)
+    {
+        return;
+    }
     delete this->m->fis;
     this->m->fis = 0;
 }
@@ -82,6 +87,10 @@ void
 ClosedFileInputSource::rewind()
 {
     this->m->offset = 0;
+    if (this->m->fis)
+    {
+        this->m->fis->rewind();
+    }
 }
 
 size_t
@@ -101,3 +110,13 @@ ClosedFileInputSource::unreadCh(char ch)
     // Don't call after -- the file has to stay open after this
     // operation.
 }
+
+void
+ClosedFileInputSource::stayOpen(bool val)
+{
+    this->m->stay_open = val;
+    if ((! val) && this->m->fis)
+    {
+        after();
+    }
+}