Add interface for performing long tasks in background, while giving a

progress indication.

6 files changed, 187 insertions, 30 deletions

diff --git a/libdimension/Makefile.am b/libdimension/Makefile.am
index 2b5784a..d4d01ec 100644
--- a/libdimension/Makefile.am
+++ b/libdimension/Makefile.am
@@ -17,10 +17,10 @@
 ## along with this program.  If not, see <http://www.gnu.org/licenses/>. ##
 ###########################################################################
 
-nobase_include_HEADERS = dimension.h dimension/array.h dimension/camera.h dimension/canvas.h dimension/color.h dimension/cube.h dimension/error.h dimension/geometry.h dimension/png.h dimension/object.h dimension/scene.h dimension/sphere.h
+nobase_include_HEADERS = dimension.h dimension/array.h dimension/camera.h dimension/canvas.h dimension/color.h dimension/cube.h dimension/error.h dimension/geometry.h dimension/png.h dimension/progress.h dimension/object.h dimension/scene.h dimension/sphere.h
 
 lib_LTLIBRARIES = libdimension.la
 
-libdimension_la_SOURCES = $(nobase_include_HEADERS) array.c camera.c canvas.c color.c cube.c error.c geometry.c png.c object.c raytrace.c scene.c sphere.c
+libdimension_la_SOURCES = $(nobase_include_HEADERS) array.c camera.c canvas.c color.c cube.c error.c geometry.c png.c progress.c object.c raytrace.c scene.c sphere.c
 libdimension_la_LDFLAGS = -version-info 0:0:0
 libdimension_la_LIBADD  = -lm -lpthread -lpng
diff --git a/libdimension/array.c b/libdimension/array.c
index c106f2f..f0378cf 100644
--- a/libdimension/array.c
+++ b/libdimension/array.c
@@ -25,7 +25,6 @@
 /* The raw implementations, which don't do any thread synchronicity */
 static void dmnsn_array_get_impl(const dmnsn_array *array, size_t i, void *obj);
 static void dmnsn_array_set_impl(dmnsn_array *array, size_t i, const void *obj);
-static void dmnsn_array_resize_impl(dmnsn_array *array, size_t length);
 
 dmnsn_array *
 dmnsn_new_array(size_t obj_size)
@@ -73,7 +72,7 @@ dmnsn_array_pop(dmnsn_array *array, void *obj)
 {
   dmnsn_array_wrlock(array);
   dmnsn_array_get_impl(array, array->length - 1, obj);
-  dmnsn_array_resize_impl(array, array->length - 1);
+  dmnsn_array_resize_unlocked(array, array->length - 1);
   dmnsn_array_unlock(array);
 }
 
@@ -97,30 +96,21 @@ void
 dmnsn_array_resize(dmnsn_array *array, size_t length)
 {
   dmnsn_array_wrlock(array);
-  dmnsn_array_resize_impl(array, length);
+  dmnsn_array_resize_unlocked(array, length);
   dmnsn_array_unlock(array);
 }
 
-static void
-dmnsn_array_get_impl(const dmnsn_array *array, size_t i, void *obj)
+void *
+dmnsn_array_at(dmnsn_array *array, size_t i)
 {
   if (i >= array->length) {
     dmnsn_error(DMNSN_SEVERITY_HIGH, "Array index out of bounds.");
   }
-  memcpy(obj, array->ptr + array->obj_size*i, array->obj_size);
-}
-
-static void
-dmnsn_array_set_impl(dmnsn_array *array, size_t i, const void *obj)
-{
-  if (i >= array->length) {
-    dmnsn_array_resize_impl(array, i + 1);
-  }
-  memcpy(array->ptr + array->obj_size*i, obj, array->obj_size);
+  return array->ptr + array->obj_size*i;
 }
 
-static void
-dmnsn_array_resize_impl(dmnsn_array *array, size_t length)
+void
+dmnsn_array_resize_unlocked(dmnsn_array *array, size_t length)
 {
   if (length > array->capacity) {
     array->capacity = length*2; /* We are greedy */
@@ -133,15 +123,6 @@ dmnsn_array_resize_impl(dmnsn_array *array, size_t length)
   array->length = length;
 }
 
-void *
-dmnsn_array_at(dmnsn_array *array, size_t i)
-{
-  if (i >= array->length) {
-    dmnsn_error(DMNSN_SEVERITY_HIGH, "Array index out of bounds.");
-  }
-  return array->ptr + array->obj_size*i;
-}
-
 void
 dmnsn_array_rdlock(const dmnsn_array *array)
 {
@@ -173,3 +154,21 @@ dmnsn_array_unlock(const dmnsn_array *array)
     dmnsn_error(DMNSN_SEVERITY_MEDIUM, "Couldn't unlock array.");
   }
 }
+
+static void
+dmnsn_array_get_impl(const dmnsn_array *array, size_t i, void *obj)
+{
+  if (i >= array->length) {
+    dmnsn_error(DMNSN_SEVERITY_HIGH, "Array index out of bounds.");
+  }
+  memcpy(obj, array->ptr + array->obj_size*i, array->obj_size);
+}
+
+static void
+dmnsn_array_set_impl(dmnsn_array *array, size_t i, const void *obj)
+{
+  if (i >= array->length) {
+    dmnsn_array_resize_unlocked(array, i + 1);
+  }
+  memcpy(array->ptr + array->obj_size*i, obj, array->obj_size);
+}
diff --git a/libdimension/dimension.h b/libdimension/dimension.h
index ba47487..bdf298e 100644
--- a/libdimension/dimension.h
+++ b/libdimension/dimension.h
@@ -28,6 +28,7 @@ extern "C" {
 
 #include <dimension/error.h>
 #include <dimension/array.h>
+#include <dimension/progress.h>
 #include <dimension/geometry.h>
 #include <dimension/color.h>
 #include <dimension/canvas.h>
diff --git a/libdimension/dimension/array.h b/libdimension/dimension/array.h
index 30a119d..5abdf48 100644
--- a/libdimension/dimension/array.h
+++ b/libdimension/dimension/array.h
@@ -48,10 +48,11 @@ void dmnsn_array_set(dmnsn_array *array, size_t i, const void *obj);
 
 void dmnsn_array_resize(dmnsn_array *array, size_t length);
 
-/* Thread-unsafe!  Don't give multiple threads the same raw pointer... */
+/* Manual locking */
+
 void *dmnsn_array_at(dmnsn_array *array, size_t i);
+void dmnsn_array_resize_unlocked(dmnsn_array *array, size_t length);
 
-/* Manual locking */
 void dmnsn_array_rdlock(const dmnsn_array *array);
 void dmnsn_array_wrlock(dmnsn_array *array);
 void dmnsn_array_unlock(const dmnsn_array *array);
diff --git a/libdimension/dimension/progress.h b/libdimension/dimension/progress.h
new file mode 100644
index 0000000..d436b5d
--- /dev/null
+++ b/libdimension/dimension/progress.h
@@ -0,0 +1,53 @@
+/*************************************************************************
+ * Copyright (C) 2008 Tavian Barnes <tavianator@gmail.com>               *
+ *                                                                       *
+ * This file is part of The Dimension Library.                           *
+ *                                                                       *
+ * The Dimension Library is free software; you can redistribute it and/  *
+ * or modify it under the terms of the GNU Lesser General Public License *
+ * as published by the Free Software Foundation; either version 3 of the *
+ * License, or (at your option) any later version.                       *
+ *                                                                       *
+ * The Dimension Library is distributed in the hope that it will be      *
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty   *
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+#ifndef DIMENSION_PROGRESS_H
+#define DIMENSION_PROGRESS_H
+
+#include <pthread.h>
+
+/* A single element in an array for dmnsn_progress.  Progress of this item is
+   progress/total. */
+typedef struct {
+  unsigned int progress, total;
+} dmnsn_progress_element;
+
+typedef struct {
+  /* Array of progress elements.  Progress is given by P(0), where
+     P(i) = (elements[i].progress + P(i + 1))/elements[i].total. */
+  dmnsn_array *elements;
+
+  /* The worker thread */
+  pthread_t thread;
+} dmnsn_progress;
+
+dmnsn_progress *dmnsn_new_progress();
+void dmnsn_delete_progress(dmnsn_progress *progress);
+
+/* This joins the worker thread and returns it's integer return value in
+   addition to deleting `progress' */
+int dmnsn_finish_progress(dmnsn_progress *progress);
+
+double dmnsn_get_progress(const dmnsn_progress* progress);
+
+void dmnsn_new_progress_element(dmnsn_progress* progress, unsigned int total);
+void dmnsn_increment_progress(dmnsn_progress* progress);
+
+#endif /* DIMENSION_PROGRESS_H */
diff --git a/libdimension/progress.c b/libdimension/progress.c
new file mode 100644
index 0000000..e072f5d
--- /dev/null
+++ b/libdimension/progress.c
@@ -0,0 +1,103 @@
+/*************************************************************************
+ * Copyright (C) 2008 Tavian Barnes <tavianator@gmail.com>               *
+ *                                                                       *
+ * This file is part of The Dimension Library.                           *
+ *                                                                       *
+ * The Dimension Library is free software; you can redistribute it and/  *
+ * or modify it under the terms of the GNU Lesser General Public License *
+ * as published by the Free Software Foundation; either version 3 of the *
+ * License, or (at your option) any later version.                       *
+ *                                                                       *
+ * The Dimension Library is distributed in the hope that it will be      *
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty   *
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+#include "dimension.h"
+#include <pthread.h>
+#include <stdlib.h> /* For malloc */
+
+dmnsn_progress *
+dmnsn_new_progress()
+{
+  dmnsn_progress *progress = malloc(sizeof(dmnsn_progress));
+  if (progress) {
+    progress->elements = dmnsn_new_array(sizeof(dmnsn_progress_element));
+  }
+  return progress;
+}
+
+void
+dmnsn_delete_progress(dmnsn_progress *progress)
+{
+  if (progress) {
+    dmnsn_delete_array(progress->elements);
+    free(progress);
+  }
+}
+
+int dmnsn_finish_progress(dmnsn_progress *progress)
+{
+  void *ptr;
+  int retval = 1;
+
+  if (progress) {
+    if (pthread_join(progress->thread, &ptr) != 0) {
+      /* Medium severity because an unjoined thread likely means that the thread
+         is incomplete or invalid */
+      dmnsn_error(DMNSN_SEVERITY_MEDIUM, "Joining worker thread failed.");
+    } else if (ptr) {
+      retval = *(int *)ptr;
+      free(ptr);
+    }
+    dmnsn_delete_progress(progress);
+  }
+
+  return retval;
+}
+
+double
+dmnsn_get_progress(const dmnsn_progress* progress)
+{
+  dmnsn_progress_element *element;
+  double prog = 0.0;
+  unsigned int i;
+
+  dmnsn_array_rdlock(progress->elements);
+  for (i = 0; i < progress->elements->length; ++i) {
+    element = dmnsn_array_at(progress->elements,
+                             progress->elements->length - i - 1);
+    prog += element->progress;
+    prog /= element->total;
+  }
+  dmnsn_array_unlock(progress->elements);
+
+  return prog;
+}
+
+void
+dmnsn_new_progress_element(dmnsn_progress* progress, unsigned int total)
+{
+  dmnsn_progress_element element = { .progress = 0, .total = total };
+  dmnsn_array_push(progress->elements, &element);
+}
+
+void
+dmnsn_increment_progress(dmnsn_progress* progress)
+{
+  dmnsn_progress_element *element;
+
+  dmnsn_array_wrlock(progress->elements);
+  element = dmnsn_array_at(progress->elements, progress->elements->length - 1);
+  ++element->progress;
+  if (element->progress >= element->total) {
+    dmnsn_array_resize_unlocked(progress->elements,
+                                progress->elements->length - 1);
+  }
+  dmnsn_array_unlock(progress->elements);
+}