Move chromeos specific utility functions for display to chromeos/display

chromeos/display/output_util.cc

+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chromeos/display/output_util.h"
+
+#include <X11/Xlib.h>
+#include <X11/extensions/Xrandr.h>
+#include <X11/Xatom.h>
+
+#include "base/message_loop.h"
+#include "base/string_util.h"
+#include "base/sys_byteorder.h"
+
+namespace chromeos {
+namespace {
+
+// Prefixes for the built-in displays.
+const char kInternal_LVDS[] = "LVDS";
+const char kInternal_eDP[] = "eDP";
+
+// Returns 64-bit persistent ID for the specified manufacturer's ID and
+// product_code, and the index of the output it is connected to.
+// |output_index| is used to distinguish the displays of the same type. For
+// example, swapping two identical display between two outputs will not be
+// treated as swap. The 'serial number' field in EDID isn't used here because
+// it is not guaranteed to have unique number and it may have the same fixed
+// value (like 0).
+int64 GetID(uint16 manufacturer_id,
+            uint16 product_code,
+            uint8 output_index) {
+  return ((static_cast<int64>(manufacturer_id) << 24) |
+          (static_cast<int64>(product_code) << 8) | output_index);
+}
+
+bool IsRandRAvailable() {
+  int randr_version_major = 0;
+  int randr_version_minor = 0;
+  static bool is_randr_available = XRRQueryVersion(
+      base::MessagePumpAuraX11::GetDefaultXDisplay(),
+      &randr_version_major, &randr_version_minor);
+  return is_randr_available;
+}
+
+// Get the EDID data from the |output| and stores to |prop|. |nitem| will store
+// the number of characters |prop| will have. It doesn't take the ownership of
+// |prop|, so caller must release it by XFree().
+// Returns true if EDID property is successfully obtained. Otherwise returns
+// false and does not touch |prop| and |nitems|.
+bool GetEDIDProperty(XID output, unsigned long* nitems, unsigned char** prop) {
+  if (!IsRandRAvailable())
+    return false;
+
+  Display* display = base::MessagePumpAuraX11::GetDefaultXDisplay();
+
+  static Atom edid_property = XInternAtom(
+      base::MessagePumpAuraX11::GetDefaultXDisplay(),
+      RR_PROPERTY_RANDR_EDID, false);
+
+  bool has_edid_property = false;
+  int num_properties = 0;
+  Atom* properties = XRRListOutputProperties(display, output, &num_properties);
+  for (int i = 0; i < num_properties; ++i) {
+    if (properties[i] == edid_property) {
+      has_edid_property = true;
+      break;
+    }
+  }
+  XFree(properties);
+  if (!has_edid_property)
+    return false;
+
+  Atom actual_type;
+  int actual_format;
+  unsigned long bytes_after;
+  XRRGetOutputProperty(display,
+                       output,
+                       edid_property,
+                       0,                // offset
+                       128,              // length
+                       false,            // _delete
+                       false,            // pending
+                       AnyPropertyType,  // req_type
+                       &actual_type,
+                       &actual_format,
+                       nitems,
+                       &bytes_after,
+                       prop);
+  DCHECK_EQ(XA_INTEGER, actual_type);
+  DCHECK_EQ(8, actual_format);
+  return true;
+}
+
+// Gets some useful data from the specified output device, such like
+// manufacturer's ID, product code, and human readable name. Returns false if it
+// fails to get those data and doesn't touch manufacturer ID/product code/name.
+// NULL can be passed for unwanted output parameters.
+bool GetOutputDeviceData(XID output,
+                         uint16* manufacturer_id,
+                         uint16* product_code,
+                         std::string* human_readable_name) {
+  unsigned long nitems = 0;
+  unsigned char *prop = NULL;
+  if (!GetEDIDProperty(output, &nitems, &prop))
+    return false;
+
+  bool result = ParseOutputDeviceData(
+      prop, nitems, manufacturer_id, product_code, human_readable_name);
+  XFree(prop);
+  return result;
+}
+
+}  // namespace
+
+std::string GetDisplayName(XID output_id) {
+  std::string display_name;
+  GetOutputDeviceData(output_id, NULL, NULL, &display_name);
+  return display_name;
+}
+
+bool GetDisplayId(XID output_id, size_t output_index, int64* display_id_out) {
+  uint16 manufacturer_id = 0;
+  uint16 product_code = 0;
+  if (GetOutputDeviceData(
+          output_id, &manufacturer_id, &product_code, NULL) &&
+      manufacturer_id != 0) {
+    // An ID based on display's index will be assigned later if this call
+    // fails.
+    *display_id_out = GetID(manufacturer_id, product_code, output_index);
+    return true;
+  }
+  return false;
+}
+
+bool ParseOutputDeviceData(const unsigned char* prop,
+                           unsigned long nitems,
+                           uint16* manufacturer_id,
+                           uint16* product_code,
+                           std::string* human_readable_name) {
+  // See http://en.wikipedia.org/wiki/Extended_display_identification_data
+  // for the details of EDID data format.  We use the following data:
+  //   bytes 8-9: manufacturer EISA ID, in big-endian
+  //   bytes 10-11: represents product code, in little-endian
+  //   bytes 54-125: four descriptors (18-bytes each) which may contain
+  //     the display name.
+  const unsigned int kManufacturerOffset = 8;
+  const unsigned int kManufacturerLength = 2;
+  const unsigned int kProductCodeOffset = 10;
+  const unsigned int kProductCodeLength = 2;
+  const unsigned int kDescriptorOffset = 54;
+  const unsigned int kNumDescriptors = 4;
+  const unsigned int kDescriptorLength = 18;
+  // The specifier types.
+  const unsigned char kMonitorNameDescriptor = 0xfc;
+
+  if (manufacturer_id) {
+    if (nitems < kManufacturerOffset + kManufacturerLength) {
+      LOG(ERROR) << "too short EDID data: manifacturer id";
+      return false;
+    }
+
+    *manufacturer_id =
+        *reinterpret_cast<const uint16*>(prop + kManufacturerOffset);
+#if defined(ARCH_CPU_LITTLE_ENDIAN)
+    *manufacturer_id = base::ByteSwap(*manufacturer_id);
+#endif
+  }
+
+  if (product_code) {
+    if (nitems < kProductCodeOffset + kProductCodeLength) {
+      LOG(ERROR) << "too short EDID data: product code";
+      return false;
+    }
+
+    *product_code = base::ByteSwapToLE16(
+        *reinterpret_cast<const uint16*>(prop + kProductCodeOffset));
+  }
+
+  if (!human_readable_name)
+    return true;
+
+  human_readable_name->clear();
+  for (unsigned int i = 0; i < kNumDescriptors; ++i) {
+    if (nitems < kDescriptorOffset + (i + 1) * kDescriptorLength)
+      break;
+
+    const unsigned char* desc_buf =
+        prop + kDescriptorOffset + i * kDescriptorLength;
+    // If the descriptor contains the display name, it has the following
+    // structure:
+    //   bytes 0-2, 4: \0
+    //   byte 3: descriptor type, defined above.
+    //   bytes 5-17: text data, ending with \r, padding with spaces
+    // we should check bytes 0-2 and 4, since it may have other values in
+    // case that the descriptor contains other type of data.
+    if (desc_buf[0] == 0 && desc_buf[1] == 0 && desc_buf[2] == 0 &&
+        desc_buf[4] == 0) {
+      if (desc_buf[3] == kMonitorNameDescriptor) {
+        std::string found_name(
+            reinterpret_cast<const char*>(desc_buf + 5), kDescriptorLength - 5);
+        TrimWhitespaceASCII(found_name, TRIM_TRAILING, human_readable_name);
+        break;
+      }
+    }
+  }
+
+  if (human_readable_name->empty()) {
+    LOG(ERROR) << "invalid EDID: empty readable name";
+    return false;
+  }
+
+  // Verify if the |human_readable_name| consists of printable characters only.
+  for (size_t i = 0; i < human_readable_name->size(); ++i) {
+    char c = (*human_readable_name)[i];
+    if (!isascii(c) || !isprint(c)) {
+      human_readable_name->clear();
+      LOG(ERROR) << "invalid EDID: human unreadable char in name";
+      return false;
+    }
+  }
+
+  return true;
+}
+
+bool GetOutputOverscanFlag(XID output, bool* flag) {
+  unsigned long nitems = 0;
+  unsigned char *prop = NULL;
+  if (!GetEDIDProperty(output, &nitems, &prop))
+    return false;
+
+  bool found = ParseOutputOverscanFlag(prop, nitems, flag);
+  XFree(prop);
+  return found;
+}
+
+bool ParseOutputOverscanFlag(const unsigned char* prop,
+                             unsigned long nitems,
+                             bool *flag) {
+  // See http://en.wikipedia.org/wiki/Extended_display_identification_data
+  // for the extension format of EDID.  Also see EIA/CEA-861 spec for
+  // the format of the extensions and how video capability is encoded.
+  //  - byte 0: tag.  should be 02h.
+  //  - byte 1: revision.  only cares revision 3 (03h).
+  //  - byte 4-: data block.
+  const unsigned int kExtensionBase = 128;
+  const unsigned int kExtensionSize = 128;
+  const unsigned int kNumExtensionsOffset = 126;
+  const unsigned int kDataBlockOffset = 4;
+  const unsigned char kCEAExtensionTag = '\x02';
+  const unsigned char kExpectedExtensionRevision = '\x03';
+  const unsigned char kExtendedTag = 7;
+  const unsigned char kExtendedVideoCapabilityTag = 0;
+  const unsigned int kPTOverscan = 4;
+  const unsigned int kITOverscan = 2;
+  const unsigned int kCEOverscan = 0;
+
+  if (nitems <= kNumExtensionsOffset)
+    return false;
+
+  unsigned char num_extensions = prop[kNumExtensionsOffset];
+
+  for (size_t i = 0; i < num_extensions; ++i) {
+    // Skip parsing the whole extension if size is not enough.
+    if (nitems < kExtensionBase + (i + 1) * kExtensionSize)
+      break;
+
+    const unsigned char* extension = prop + kExtensionBase + i * kExtensionSize;
+    unsigned char tag = extension[0];
+    unsigned char revision = extension[1];
+    if (tag != kCEAExtensionTag || revision != kExpectedExtensionRevision)
+      continue;
+
+    unsigned char timing_descriptors_start =
+        std::min(extension[2], static_cast<unsigned char>(kExtensionSize));
+    const unsigned char* data_block = extension + kDataBlockOffset;
+    while (data_block < extension + timing_descriptors_start) {
+      // A data block is encoded as:
+      // - byte 1 high 3 bits: tag. '07' for extended tags.
+      // - byte 1 remaining bits: the length of data block.
+      // - byte 2: the extended tag.  '0' for video capability.
+      // - byte 3: the capability.
+      unsigned char tag = data_block[0] >> 5;
+      unsigned char payload_length = data_block[0] & 0x1f;
+      if (static_cast<unsigned long>(data_block + payload_length - prop) >
+          nitems)
+        break;
+
+      if (tag != kExtendedTag || payload_length < 2) {
+        data_block += payload_length + 1;
+        continue;
+      }
+
+      unsigned char extended_tag_code = data_block[1];
+      if (extended_tag_code != kExtendedVideoCapabilityTag) {
+        data_block += payload_length + 1;
+        continue;
+      }
+
+      // The difference between preferred, IT, and CE video formats
+      // doesn't matter. Sets |flag| to true if any of these flags are true.
+      if ((data_block[2] & (1 << kPTOverscan)) ||
+          (data_block[2] & (1 << kITOverscan)) ||
+          (data_block[2] & (1 << kCEOverscan))) {
+        *flag = true;
+      } else {
+        *flag = false;
+      }
+      return true;
+    }
+  }
+
+  return false;
+}
+
+bool IsInternalOutputName(const std::string& name) {
+  return name.find(kInternal_LVDS) == 0 || name.find(kInternal_eDP) == 0;
+}
+
+}  // namespace chromeos