[gparted] Refactor load_proc_partitions_info_cache() a bit (#131)

[Curtis Gedak <gedakc src gnome org>]

commit 52930f30ae8dc2c9dd1f64d2df654d9f1a1afb8a
Author: Mike Fleetwood <mike fleetwood googlemail com>
Date:   Thu Jan 21 22:01:08 2021 +0000

    Refactor load_proc_partitions_info_cache() a bit (#131)
    
    Put whole disk device name matching code into a helper function to make
    the /proc/partition parsing code easier to understand.
    
    Closes #131 - GParted hangs when non-named device is hung

 include/Proc_Partitions_Info.h |  2 +
 src/Proc_Partitions_Info.cc    | 93 ++++++++++++++++++++++--------------------
 2 files changed, 50 insertions(+), 45 deletions(-)
---
diff --git a/include/Proc_Partitions_Info.h b/include/Proc_Partitions_Info.h
index 23b4348a..5769fb98 100644
--- a/include/Proc_Partitions_Info.h
+++ b/include/Proc_Partitions_Info.h
@@ -39,6 +39,8 @@ public:
 private:
        static void initialize_if_required();
        static void load_proc_partitions_info_cache();
+       static bool is_whole_disk_device_name(const Glib::ustring& name);
+
        static bool proc_partitions_info_cache_initialized ;
        static std::vector<Glib::ustring> device_paths_cache ;
 };
diff --git a/src/Proc_Partitions_Info.cc b/src/Proc_Partitions_Info.cc
index f3aa77fc..dc94ec0e 100644
--- a/src/Proc_Partitions_Info.cc
+++ b/src/Proc_Partitions_Info.cc
@@ -61,66 +61,69 @@ void Proc_Partitions_Info::load_proc_partitions_info_cache()
        if ( proc_partitions )
        {
                std::string line ;
-               Glib::ustring device;
 
                while ( getline( proc_partitions, line ) )
                {
-                       // Pre-populate BlockSpecial cache with major, minor numbers of
-                       // all names found from /proc/partitions.
                        Glib::ustring name = Utils::regexp_label( line,
                                
"^[[:blank:]]*[[:digit:]]+[[:blank:]]+[[:digit:]]+[[:blank:]]+[[:digit:]]+[[:blank:]]+([[:graph:]]+)$" );
                        if ( name == "" )
                                continue;
+
+                       // Pre-populate BlockSpecial cache to avoid stat() call for all
+                       // entries from /proc/partitions.
                        unsigned long maj;
                        unsigned long min;
                        if ( sscanf( line.c_str(), "%lu %lu", &maj, &min ) != 2 )
                                continue;
                        BlockSpecial::register_block_special( "/dev/" + name, maj, min );
 
-                       // Recognise only whole disk device names, excluding partitions,
-                       // from /proc/partitions and save in this cache.
-
-                       //Whole disk devices are the ones we want.
-                       //Device names without a trailing digit refer to the whole disk.
-                       device = Utils::regexp_label( name, "^([^0-9]+)$" );
-
-                       //Recognize /dev/md* devices (Linux software RAID - mdadm).
-                       //E.g., device = /dev/md127, partition = /dev/md127p1
-                       if ( device == "" )
-                               device = Utils::regexp_label( name, "^(md[0-9]+)$" );
-
-                       //Recognize /dev/mmcblk* devices.
-                       //E.g., device = /dev/mmcblk0, partition = /dev/mmcblk0p1
-                       if ( device == "" )
-                               device = Utils::regexp_label( name, "^(mmcblk[0-9]+)$" );
-
-                       // Recognise /dev/nvme*n* devices
-                       // (Non-Volatile Memory Express devices.  SSD type devices which
-                       // plug directly into PCIe sockets).
-                       // E.g., device = /dev/nvme0n1, partition = /dev/nvme0n1p1
-                       if ( device == "" )
-                               device = Utils::regexp_label( name, "^(nvme[0-9]+n[0-9]+)$" );
-
-                       //Device names that end with a #[^p]# are HP Smart Array Devices (disks)
-                       //  E.g., device = /dev/cciss/c0d0, partition = /dev/cciss/c0d0p1
-                       //  (linux-x.y.z/Documentation/blockdev/cciss.txt)
-                       //Device names for Compaq SMART2 Intelligent Disk Array
-                       //  E.g., device = /dev/ida/c0d0, partition = /dev/ida/c0d0p1
-                       //  (linux-x.y.z/Documentation/blockdev/cpqarray.txt)
-                       //Device names for Mylex DAC960/AcceleRAID/eXtremeRAID PCI RAID
-                       //  E.g., device = /dev/rd/c0d0, partition = /dev/rd/c0d0p1
-                       //  (linux-x.y.z/Documentation/blockdev/README.DAC960)
-                       if ( device == "" )
-                               device = Utils::regexp_label( name, "^([a-z]+/c[0-9]+d[0-9]+)$" );
-
-                       if ( device != "" )
-                       {
-                               //add potential device to the list
-                               device_paths_cache.push_back( "/dev/" + device );
-                       }
+                       // Save recognised whole disk device names for later returning as
+                       // the default GParted partitionable devices.
+                       if (is_whole_disk_device_name(name))
+                               device_paths_cache.push_back("/dev/" + name);
                }
                proc_partitions .close() ;
        }
 }
 
-}//GParted
+
+// True only for whole disk device names which GParted will present by default as
+// partitionable.
+bool Proc_Partitions_Info::is_whole_disk_device_name(const Glib::ustring& name)
+{
+       // Match ordinary whole disk device names.
+       // E.g.: device = sda (partition = sda1)
+       if (Utils::regexp_label(name, "^([^0-9]+)$") != "")
+               return true;
+
+       // Match Linux software RAID (mdadm) device names.
+       // E.g.: device = md127 (partition = md127p1)
+       if (Utils::regexp_label(name, "^(md[0-9]+)$") != "")
+
+       // Match SD/MMC card whole disk devices names.
+       // E.g.: device = mmcblk0 (partition = mmcblk0p1)
+       if (Utils::regexp_label(name, "^(md[0-9]+)$") != "")
+               return true;
+
+       // Match NVME (Non-Volatile Memory Express) whole disk device names.
+       // E.g.: device = nvme0n1 (partition = nvme0n1p1)
+       if (Utils::regexp_label(name, "^(nvme[0-9]+n[0-9]+)$") != "")
+               return true;
+
+       // Match hardware RAID controller whole disk device names.
+       // * HP Smart Array (linux-x.y.z/Documentation/scsi/hpsa.rst).
+       //   E.g.: device = cciss/c0d0 (partition = cciss/c0d0p1)
+       // * Compaq SMART2 Intelligent Disk Array
+       //   (linux-x.y.z/Documentation/admin-guide/devices.txt)
+       //   E.g.: device = ida/c0d0 (partition = ida/c0d0p1)
+       // * Mylex DAC960/AcceleRAID/eXtremeRAID PCI RAID
+       //   (linux-x.y.z/Documentation/admin-guide/devices.txt)
+       //   E.g.: device = rd/c0d0 (partition = rd/c0d0p1)
+       if (Utils::regexp_label(name, "^([a-z]+/c[0-9]+d[0-9]+)$") != "")
+               return true;
+
+       return false;
+}
+
+
+} //GParted