1 files changed, 118 insertions, 0 deletions
diff --git a/FileDescriptorMeter.c b/FileDescriptorMeter.c
new file mode 100644
index 0000000..cf1ec93
--- /dev/null
+++ b/FileDescriptorMeter.c
@@ -0,0 +1,118 @@
+/*
+htop - FileDescriptorMeter.c
+(C) 2022 htop dev team
+Released under the GNU GPLv2+, see the COPYING file
+in the source distribution for its full text.
+*/
+
+#include "config.h" // IWYU pragma: keep
+
+#include "FileDescriptorMeter.h"
+
+#include <math.h>
+
+#include "CRT.h"
+#include "Macros.h"
+#include "Meter.h"
+#include "Object.h"
+#include "Platform.h"
+#include "RichString.h"
+#include "XUtils.h"
+
+
+#define FD_EFFECTIVE_UNLIMITED(x) (!isgreaterequal((double)(1<<30), (x)))
+
+static const int FileDescriptorMeter_attributes[] = {
+   FILE_DESCRIPTOR_USED,
+   FILE_DESCRIPTOR_MAX
+};
+
+static void FileDescriptorMeter_updateValues(Meter* this) {
+   this->values[0] = 0;
+   this->values[1] = 1;
+
+   Platform_getFileDescriptors(&this->values[0], &this->values[1]);
+
+   /* only print bar for first value */
+   this->curItems = 1;
+
+   /* Use maximum value for scaling of bar mode
+    *
+    * As the plain total value can be very large compared to
+    * the actually used value, this is capped in the following way:
+    *
+    * 1. If the maximum value is below (or equal to) 1<<16, use it directly
+    * 2. If the maximum value is above, use powers of 2 starting at 1<<16 and
+    *    double it until it's larger than 16 times the used file handles
+    *    (capped at the maximum number of files)
+    * 3. If the maximum is effectively unlimited (AKA > 1<<30),
+    *    Do the same as for 2, but cap at 1<<30.
+    */
+   if (this->values[1] <= 1 << 16) {
+      this->total = this->values[1];
+   } else {
+      if (this->total < 16 * this->values[0]) {
+         for (this->total = 1 << 16; this->total < 16 * this->values[0]; this->total *= 2) {
+            if (this->total >= 1 << 30) {
+               break;
+            }
+         }
+      }
+
+      if (this->total > this->values[1]) {
+         this->total = this->values[1];
+      }
+
+      if (this->total > 1 << 30) {
+         this->total = 1 << 30;
+      }
+   }
+
+   if (!isNonnegative(this->values[0])) {
+      xSnprintf(this->txtBuffer, sizeof(this->txtBuffer), "unknown/unknown");
+   } else if (FD_EFFECTIVE_UNLIMITED(this->values[1])) {
+      xSnprintf(this->txtBuffer, sizeof(this->txtBuffer), "%.0lf/unlimited", this->values[0]);
+   } else {
+      xSnprintf(this->txtBuffer, sizeof(this->txtBuffer), "%.0lf/%.0lf", this->values[0], this->values[1]);
+   }
+}
+
+static void FileDescriptorMeter_display(const Object* cast, RichString* out) {
+   const Meter* this = (const Meter*)cast;
+   char buffer[50];
+   int len;
+
+   if (!isNonnegative(this->values[0])) {
+      RichString_appendAscii(out, CRT_colors[METER_TEXT], "unknown");
+      return;
+   }
+
+   RichString_appendAscii(out, CRT_colors[METER_TEXT], "used: ");
+   len = xSnprintf(buffer, sizeof(buffer), "%.0lf", this->values[0]);
+   RichString_appendnAscii(out, CRT_colors[FILE_DESCRIPTOR_USED], buffer, len);
+
+   RichString_appendAscii(out, CRT_colors[METER_TEXT], " max: ");
+   if (FD_EFFECTIVE_UNLIMITED(this->values[1])) {
+      RichString_appendAscii(out, CRT_colors[FILE_DESCRIPTOR_MAX], "unlimited");
+   } else {
+      len = xSnprintf(buffer, sizeof(buffer), "%.0lf", this->values[1]);
+      RichString_appendnAscii(out, CRT_colors[FILE_DESCRIPTOR_MAX], buffer, len);
+   }
+}
+
+const MeterClass FileDescriptorMeter_class = {
+   .super = {
+      .extends = Class(Meter),
+      .delete = Meter_delete,
+      .display = FileDescriptorMeter_display,
+   },
+   .updateValues = FileDescriptorMeter_updateValues,
+   .defaultMode = TEXT_METERMODE,
+   .maxItems = 2,
+   .total = 65536.0,
+   .attributes = FileDescriptorMeter_attributes,
+   .name = "FileDescriptors",
+   .uiName = "File Descriptors",
+   .caption = "FDs: ",
+   .description = "Number of allocated/available file descriptors"
+};