add function for listing available methods + add __attribute__((cold)) and __attribute__((hot))

Signed-off-by: Mattias Andrée <maandree@operamail.com>

3 files changed, 160 insertions, 6 deletions

diff --git a/src/libgamma-facade.c b/src/libgamma-facade.c
index 07dfd9b..81c6d8a 100644
--- a/src/libgamma-facade.c
+++ b/src/libgamma-facade.c
@@ -56,6 +56,7 @@
 # endif
 #endif
 
+#include <unistd.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <stdlib.h>
@@ -74,6 +75,137 @@
 #endif
 
 
+
+#ifdef HAVE_GAMMA_METHODS
+# ifdef HAVE_GAMMA_METHOD_LINUX_DRM
+/**
+ * Test whether a file descriptor refers to a VT
+ * 
+ * @param   fd  The file descriptor
+ * @return      Whether the file descriptor refers to a VT
+ */
+static int libgamma_is_vt_proper(int fd)
+{
+  char buf[32];
+  char digit0;
+  
+  if (ttyname_r(fd, buf, sizeof(buf) / sizeof(char)))
+    return 0;
+  
+  if (strstr(buf, "/dev/tty") != buf)
+    return 0;
+  
+  digit0 = buf[strlen("/dev/tty")];
+  return ('1' <= digit0) && (digit0 <= '9');
+}
+# endif
+
+
+/**
+ * Test the availability of an adjustment method
+ * 
+ * @param  method     The adjustment method
+ * @param  operation  Allowed values:
+ *                      0: Pass if the environment suggests it will work but is not fake.
+ *                      1: Pass if the environment suggests it will work.
+ *                      2: Pass if real and not fake.
+ *                      3: Pass if real.
+ *                      4: Always pass.
+ *                    Other values invoke undefined behaviour.
+ * @return            Whether the test passed
+ */
+static int libgamma_list_method_test(int method, int operation)
+{
+  libgamma_method_capabilities_t caps;
+  libgamma_method_capabilities(&caps, method);
+  
+  switch (operation)
+    {
+    case 0: /* Methods that the environment suggests will work, excluding fake. */
+      if (caps.fake)
+	return 0;
+      /* Fall through. */
+      
+    case 1: /* Methods that the environment suggests will work, including fake. */
+      if (caps.real == 0)
+	return 0;
+#ifdef HAVE_GAMMA_METHOD_LINUX_DRM
+      if (method == GAMMA_METHOD_LINUX_DRM)
+	return libgamma_is_vt_proper(STDIN_FILENO) ||
+	       libgamma_is_vt_proper(STDOUT_FILENO) ||
+	       libgamma_is_vt_proper(STDERR_FILENO);
+#endif
+#ifdef HAVE_GAMMA_METHOD_DUMMY
+      if (method == GAMMA_METHOD_DUMMY)
+	return 0;
+#endif
+      return caps.default_site_known;
+      
+    case 2: /* All real non-fake methods. */
+      return caps.real && (caps.fake == 0);
+      
+    case 3: /* All real methods. */
+      return caps.real;
+      
+    default: /* All methods. */
+      return 1;
+    }
+}
+#endif
+
+
+/**
+ * List available adjustment methods by their order of preference based on the environment
+ * 
+ * @param  methods    Output array of methods, should be able to hold `GAMMA_METHOD_COUNT` elements
+ * @param  operation  Allowed values:
+ *                      0: Methods that the environment suggests will work, excluding fake.
+ *                      1: Methods that the environment suggests will work, including fake.
+ *                      2: All real non-fake methods.
+ *                      3: All real methods.
+ *                      4: All methods.
+ *                    Other values invoke undefined behaviour.
+ * @return            The number of element that have been stored in `methods`
+ */
+size_t libgamma_list_methods(int* methods, int operation)
+{
+#ifdef HAVE_NO_GAMMA_METHODS
+  (void) methods;
+  (void) operation;
+  return 0;
+#else
+  size_t n = 0;
+  
+#ifdef HAVE_GAMMA_METHOD_RANDR
+  if (libgamma_list_method_test(GAMMA_METHOD_RANDR, operation))
+    methods[n++] = GAMMA_METHOD_RANDR;
+#endif
+#ifdef HAVE_GAMMA_METHOD_VIDMODE
+  if (libgamma_list_method_test(GAMMA_METHOD_VIDMODE, operation))
+    methods[n++] = GAMMA_METHOD_VIDMODE;
+#endif
+#ifdef HAVE_GAMMA_METHOD_LINUX_DRM
+  if (libgamma_list_method_test(GAMMA_METHOD_LINUX_DRM, operation))
+    methods[n++] = GAMMA_METHOD_LINUX_DRM;
+#endif
+#ifdef HAVE_GAMMA_METHOD_W32_GDI
+  if (libgamma_list_method_test(GAMMA_METHOD_W32_GDI, operation))
+    methods[n++] = GAMMA_METHOD_W32_GDI;
+#endif
+#ifdef HAVE_GAMMA_METHOD_QUARTZ_CORE_GRAPHICS
+  if (libgamma_list_method_test(GAMMA_METHOD_QUARTZ_CORE_GRAPHICS, operation))
+    methods[n++] = GAMMA_METHOD_QUARTZ_CORE_GRAPHICS;
+#endif
+#ifdef HAVE_GAMMA_METHOD_DUMMY
+  if (libgamma_list_method_test(GAMMA_METHOD_DUMMY, operation))
+    methods[n++] = GAMMA_METHOD_DUMMY;
+#endif
+  
+  return n;
+#endif
+}
+
+
 /**
  * Return the capabilities of an adjustment method
  * 
diff --git a/src/libgamma-facade.h b/src/libgamma-facade.h
index a8e7636..19581a0 100644
--- a/src/libgamma-facade.h
+++ b/src/libgamma-facade.h
@@ -70,6 +70,21 @@ typedef double libgamma_gamma_rampsd_fun(double encoding);
 
 
 /**
+ * List available adjustment methods by their order of preference based on the environment
+ * 
+ * @param  methods    Output array of methods, should be able to hold `GAMMA_METHOD_COUNT` elements
+ * @param  operation  Allowed values:
+ *                      0: Methods that the environment suggests will work, excluding fake.
+ *                      1: Methods that the environment suggests will work, including fake.
+ *                      2: All real non-fake methods.
+ *                      3: All real methods.
+ *                      4: All methods.
+ *                    Other values invoke undefined behaviour.
+ * @return            The number of element that have been stored in `methods`
+ */
+size_t libgamma_list_methods(int* methods, int operation);
+
+/**
  * Return the capabilities of an adjustment method
  * 
  * @param  this    The data structure to fill with the method's capabilities
@@ -303,7 +318,7 @@ int libgamma_crtc_get_gamma_ramps(libgamma_crtc_state_t* restrict this,
  *                 error identifier provided by this library
  */
 int libgamma_crtc_set_gamma_ramps(libgamma_crtc_state_t* restrict this,
-				  libgamma_gamma_ramps_t ramps);
+				  libgamma_gamma_ramps_t ramps) __attribute__((hot));
 
 
 /**
@@ -411,7 +426,7 @@ int libgamma_crtc_set_gamma_rampsd(libgamma_crtc_state_t* restrict this,
 int libgamma_crtc_set_gamma_ramps_f(libgamma_crtc_state_t* restrict this,
 				    libgamma_gamma_ramps_fun* red_function,
 				    libgamma_gamma_ramps_fun* green_function,
-				    libgamma_gamma_ramps_fun* blue_function);
+				    libgamma_gamma_ramps_fun* blue_function) __attribute__((cold));
 
 /**
  * Set the gamma ramps for a CRTC, 32-bit gamma-depth function version
@@ -426,7 +441,7 @@ int libgamma_crtc_set_gamma_ramps_f(libgamma_crtc_state_t* restrict this,
 int libgamma_crtc_set_gamma_ramps32_f(libgamma_crtc_state_t* restrict this,
 				      libgamma_gamma_ramps32_fun* red_function,
 				      libgamma_gamma_ramps32_fun* green_function,
-				      libgamma_gamma_ramps32_fun* blue_function);
+				      libgamma_gamma_ramps32_fun* blue_function) __attribute__((cold));
 
 /**
  * Set the gamma ramps for a CRTC, 64-bit gamma-depth function version
@@ -441,7 +456,7 @@ int libgamma_crtc_set_gamma_ramps32_f(libgamma_crtc_state_t* restrict this,
 int libgamma_crtc_set_gamma_ramps64_f(libgamma_crtc_state_t* restrict this,
 				      libgamma_gamma_ramps64_fun* red_function,
 				      libgamma_gamma_ramps64_fun* green_function,
-				      libgamma_gamma_ramps64_fun* blue_function);
+				      libgamma_gamma_ramps64_fun* blue_function) __attribute__((cold));
 
 /**
  * Set the gamma ramps for a CRTC, `float` function version
@@ -456,7 +471,7 @@ int libgamma_crtc_set_gamma_ramps64_f(libgamma_crtc_state_t* restrict this,
 int libgamma_crtc_set_gamma_rampsf_f(libgamma_crtc_state_t* restrict this,
 				     libgamma_gamma_rampsf_fun* red_function,
 				     libgamma_gamma_rampsf_fun* green_function,
-				     libgamma_gamma_rampsf_fun* blue_function);
+				     libgamma_gamma_rampsf_fun* blue_function) __attribute__((cold));
 
 /**
  * Set the gamma ramps for a CRTC, `double` function version
@@ -471,7 +486,7 @@ int libgamma_crtc_set_gamma_rampsf_f(libgamma_crtc_state_t* restrict this,
 int libgamma_crtc_set_gamma_rampsd_f(libgamma_crtc_state_t* restrict this,
 				     libgamma_gamma_rampsd_fun* red_function,
 				     libgamma_gamma_rampsd_fun* green_function,
-				     libgamma_gamma_rampsd_fun* blue_function);
+				     libgamma_gamma_rampsd_fun* blue_function) __attribute__((cold));
 
 
 #endif
diff --git a/src/libgamma-method.h b/src/libgamma-method.h
index 8b78e4e..e79e893 100644
--- a/src/libgamma-method.h
+++ b/src/libgamma-method.h
@@ -97,6 +97,13 @@
  */
 #define GAMMA_METHOD_MAX  5
 
+/**
+ * The number adjustment methods provided by this library.
+ * Note however that this includes adjstment methods that
+ * have been removed at compile-time.
+ */
+#define GAMMA_METHOD_COUNT  (GAMMA_METHOD_MAX + 1)
+
 
 
 /**