update_engine: added partition name manipulation library methods
Added utility methods to split and merge partition device names
to help "semi-intelligently" break down full partition device
name into disk name and partition name and merge them back.
With special handling for MMC devices and similar.
Also removed inconsistent naming for the disk and partition
device names (such as "boot device", "root device", etc).
Now device names such as "/dev/sda" are referred to as
"disk name" and "/dev/sda1" as "partition name").
BUG=None
TEST=Updated and ran unit tests
Change-Id: Ica41b8c99f0120799be326af0b41324639c5cf6a
Reviewed-on: https://chromium-review.googlesource.com/187453
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
Reviewed-by: Don Garrett <dgarrett@chromium.org>
diff --git a/utils.h b/utils.h
index 3e1fd16..a84f512 100644
--- a/utils.h
+++ b/utils.h
@@ -136,14 +136,35 @@
// This WILL cross filesystem boundaries.
bool RecursiveUnlinkDir(const std::string& path);
-// Returns the root device for a partition. For example,
-// RootDevice("/dev/sda3") returns "/dev/sda". Returns an empty string
-// if the input device is not of the "/dev/xyz" form.
-std::string RootDevice(const std::string& partition_device);
+// Returns the disk device name for a partition. For example,
+// GetDiskName("/dev/sda3") returns "/dev/sda". Returns an empty string
+// if the input device is not of the "/dev/xyz#" form.
+std::string GetDiskName(const std::string& partition_name);
-// Returns the partition number, as a string, of partition_device. For example,
-// PartitionNumber("/dev/sda3") returns "3".
-std::string PartitionNumber(const std::string& partition_device);
+// Returns the partition number, of partition device name. For example,
+// GetPartitionNumber("/dev/sda3") returns 3.
+// Returns 0 on failure
+int GetPartitionNumber(const std::string& partition_name);
+
+// Splits the partition device name into the block device name and partition
+// number. For example, "/dev/sda3" will be split into {"/dev/sda", 3} and
+// "/dev/mmcblk0p2" into {"/dev/mmcblk0", 2}
+// Returns false when malformed device name is passed in.
+// If both output parameters are omitted (nullptr), can be used
+// just to test the validity of the device name. Note that the function
+// simply checks if the device name looks like a valid device, no other
+// checks are performed (i.e. it doesn't check if the device actually exists).
+bool SplitPartitionName(const std::string& partition_name,
+ std::string* out_disk_name,
+ int* out_partition_num);
+
+// Builds a partition device name from the block device name and partition
+// number. For example:
+// {"/dev/sda", 1} => "/dev/sda1"
+// {"/dev/mmcblk2", 12} => "/dev/mmcblk2p12"
+// Returns empty string when invalid parameters are passed in
+std::string MakePartitionName(const std::string& disk_name,
+ int partition_num);
// Returns the sysfs block device for a root block device. For
// example, SysfsBlockDevice("/dev/sda") returns