The Tor Browser: gfx/skia/trunk/src/core/SkUtilsArm.cpp@129ffea94266 (annotated)

gfx/skia/trunk/src/core/SkUtilsArm.cpp@129ffea94266 (annotated)

gfx/skia/trunk/src/core/SkUtilsArm.cpp

Sat, 03 Jan 2015 20:18:00 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Sat, 03 Jan 2015 20:18:00 +0100
branch: TOR_BUG_3246
changeset 7: 129ffea94266
permissions: -rw-r--r--

Conditionally enable double key logic according to:
private browsing mode or privacy.thirdparty.isolate preference and
implement in GetCookieStringCommon and FindCookie where it counts...
With some reservations of how to convince FindCookie users to test
condition and pass a nullptr when disabling double key logic.

 /*
  * Copyright 2012 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "SkUtilsArm.h"
 #if SK_ARM_NEON_IS_DYNAMIC
 #include <unistd.h>
 #include <fcntl.h>
 #include <errno.h>
 #include <string.h>
 #include <pthread.h>
 // Set USE_ANDROID_NDK_CPU_FEATURES to use the Android NDK's
 // cpu-features helper library to detect NEON at runtime. See
 // http://crbug.com/164154 to see why this is needed in Chromium
 // for Android.
 #if !defined(USE_ANDROID_NDK_CPU_FEATURES)
 #  if defined(SK_BUILD_FOR_ANDROID)
 #    define USE_ANDROID_NDK_CPU_FEATURES 1
 #  else
 #    define USE_ANDROID_NDK_CPU_FEATURES 0
 #  endif
 #endif
 #if USE_ANDROID_NDK_CPU_FEATURES
 #  include <cpu-features.h>
 #endif
 // Set NEON_DEBUG to 1 to allow debugging of the CPU features probing.
 // For now, we always set it for SK_DEBUG builds.
 #ifdef SK_DEBUG
 #  define NEON_DEBUG  1
 #else
 #  define NEON_DEBUG 0
 #endif
 #if NEON_DEBUG
 #  ifdef SK_BUILD_FOR_ANDROID
      // used to declare PROP_VALUE_MAX and __system_property_get()
 #    include <sys/system_properties.h>
 #  endif
 #endif
 // A function used to determine at runtime if the target CPU supports
 // the ARM NEON instruction set. This implementation is Linux-specific.
 static bool sk_cpu_arm_check_neon(void) {
     bool result = false;
 #if NEON_DEBUG
     // Allow forcing the mode through the environment during debugging.
 #  ifdef SK_BUILD_FOR_ANDROID
     // On Android, we use a system property
 #   define PROP_NAME  "debug.skia.arm_neon_mode"
     char prop[PROP_VALUE_MAX];
     if (__system_property_get(PROP_NAME, prop) > 0) {
 #  else
 #   define PROP_NAME   "SKIA_ARM_NEON_MODE"
     // On ARM Linux, we use an environment variable
     const char* prop = getenv(PROP_NAME);
     if (prop != NULL) {
 #  endif
         SkDebugf("%s: %s", PROP_NAME, prop);
         if (!strcmp(prop, "1")) {
             SkDebugf("Forcing ARM Neon mode to full!\n");
             return true;
         }
         if (!strcmp(prop, "0")) {
             SkDebugf("Disabling ARM NEON mode\n");
             return false;
         }
     }
     SkDebugf("Running dynamic CPU feature detection\n");
 #endif
 #if USE_ANDROID_NDK_CPU_FEATURES
   result = (android_getCpuFeatures() & ANDROID_CPU_ARM_FEATURE_NEON) != 0;
 #else  // USE_ANDROID_NDK_CPU_FEATURES
     // There is no user-accessible CPUID instruction on ARM that we can use.
     // Instead, we must parse /proc/cpuinfo and look for the 'neon' feature.
     // For example, here's a typical output (Nexus S running ICS 4.0.3):
     /*
     Processor       : ARMv7 Processor rev 2 (v7l)
     BogoMIPS        : 994.65
     Features        : swp half thumb fastmult vfp edsp thumbee neon vfpv3
     CPU implementer : 0x41
     CPU architecture: 7
     CPU variant     : 0x2
     CPU part        : 0xc08
     CPU revision    : 2
     Hardware        : herring
     Revision        : 000b
     Serial          : 3833c77d6dc000ec
     */
     char   buffer[4096];
     // If we fail any of the following, assume we don't have NEON instructions
     // This allows us to return immediately in case of error.
     result = false;
     do {
         // open /proc/cpuinfo
         int fd = TEMP_FAILURE_RETRY(open("/proc/cpuinfo", O_RDONLY));
         if (fd < 0) {
             SkDebugf("Could not open /proc/cpuinfo: %s\n", strerror(errno));
             break;
         }
         // Read the file. To simplify our search, we're going to place two
         // sentinel '\n' characters: one at the start of the buffer, and one at
         // the end. This means we reserve the first and last buffer bytes.
         buffer[0] = '\n';
         int size = TEMP_FAILURE_RETRY(read(fd, buffer+1, sizeof(buffer)-2));
         close(fd);
         if (size < 0) {  // should not happen
             SkDebugf("Could not read /proc/cpuinfo: %s\n", strerror(errno));
             break;
         }
         SkDebugf("START /proc/cpuinfo:\n%.*s\nEND /proc/cpuinfo\n",
                  size, buffer+1);
         // Compute buffer limit, and place final sentinel
         char* buffer_end = buffer + 1 + size;
         buffer_end[0] = '\n';
         // Now, find a line that starts with "Features", i.e. look for
         // '\nFeatures ' in our buffer.
         const char features[] = "\nFeatures\t";
         const size_t features_len = sizeof(features)-1;
         char*  line = (char*) memmem(buffer, buffer_end - buffer,
                                      features, features_len);
         if (line == NULL) {  // Weird, no Features line, bad kernel?
             SkDebugf("Could not find a line starting with 'Features'"
               "in /proc/cpuinfo ?\n");
             break;
         }
         line += features_len;  // Skip the "\nFeatures\t" prefix
         // Find the end of the current line
         char* line_end = (char*) memchr(line, '\n', buffer_end - line);
         if (line_end == NULL)
             line_end = buffer_end;
         // Now find an instance of 'neon' in the flags list. We want to
         // ensure it's only 'neon' and not something fancy like 'noneon'
         // so check that it follows a space.
         const char neon[] = " neon";
         const size_t neon_len = sizeof(neon)-1;
         const char* flag = (const char*) memmem(line, line_end - line,
                                                 neon, neon_len);
         if (flag == NULL)
             break;
         // Ensure it is followed by a space or a newline.
         if (flag[neon_len] != ' ' && flag[neon_len] != '\n')
             break;
         // Fine, we support Arm NEON !
         result = true;
     } while (0);
 #endif  // USE_ANDROID_NDK_CPU_FEATURES
     if (result) {
         SkDebugf("Device supports ARM NEON instructions!\n");
     } else {
         SkDebugf("Device does NOT support ARM NEON instructions!\n");
     }
     return result;
 }
 static pthread_once_t  sOnce;
 static bool            sHasArmNeon;
 // called through pthread_once()
 void sk_cpu_arm_probe_features(void) {
     sHasArmNeon = sk_cpu_arm_check_neon();
 }
 bool sk_cpu_arm_has_neon(void) {
     pthread_once(&sOnce, sk_cpu_arm_probe_features);
     return sHasArmNeon;
 }
 #endif // SK_ARM_NEON_IS_DYNAMIC

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gfx/skia/trunk/src/core/SkUtilsArm.cpp@129ffea94266 (annotated)

gfx/skia/trunk/src/core/SkUtilsArm.cpp