# 2018 December 6
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl

set testprefix shmlock

ifcapable !wal {finish_test ; return }

sqlite3 db2 test.db
sqlite3 db3 test.db

do_execsql_test 1.0 {
  PRAGMA journal_mode = wal;
  CREATE TABLE t1(a, b);
  INSERT INTO t1 VALUES(1, 2);
} {wal}
do_test 1.1 { execsql { SELECT * FROM t1 } db2 } {1 2}
do_test 1.2 { execsql { SELECT * FROM t1 } db3 } {1 2}

foreach {tn dbhandle cmd res} {
  1    db  {shared    lock   7 1}    OK
  2    db2 {exclusive lock   7 1}    BUSY
  3    db  {shared    unlock 7 1}    OK
  4    db2 {exclusive lock   7 1}    OK
  5    db  {shared    lock   7 1}    BUSY
  6    db  {exclusive lock   7 1}    BUSY
  7    db2 {exclusive unlock 7 1}    OK

  8    db  {exclusive lock   0 8}    OK
  9    db  {exclusive unlock 0 8}    OK
  10   db2 {exclusive lock   0 8}    OK
  11   db2 {exclusive unlock 0 8}    OK

  12   db  {shared    lock   0 1}    OK
  13   db2 {shared    lock   0 1}    OK
  14   db3 {shared    lock   0 1}    OK
  15   db3 {shared    unlock 0 1}    OK
  16   db3 {exclusive lock   0 1}    BUSY
  17   db2 {shared    unlock 0 1}    OK
  18   db3 {exclusive lock   0 1}    BUSY
  19   db  {shared    unlock 0 1}    OK
  20   db3 {exclusive lock   0 1}    OK
  21   db3 {exclusive unlock 0 1}    OK

  22   db  {shared    lock   3 1}    OK
  23   db2 {exclusive lock   2 2}    BUSY
  24   db  {shared    lock   2 1}    OK
  25   db2 {exclusive lock   0 5}    BUSY
  26   db2 {exclusive lock   0 4}    BUSY
  27   db2 {exclusive lock   0 3}    BUSY
  28   db  {shared    unlock 3 1}    OK
  29   db2 {exclusive lock   2 2}    BUSY
  28   db  {shared    unlock 2 1}    OK
  29   db2 {exclusive lock   2 2}    OK
  29   db2 {exclusive unlock 2 2}    OK
} {
  do_test 1.3.$tn [list vfs_shmlock $dbhandle main {*}$cmd] "SQLITE_$res"
}

db  close
db2 close
db3 close

if {[permutation]=="unix-excl"} {
  do_test 2.0 {
    for {set i 0} {$i < 256} {incr i} { 
      sqlite3 db$i test.db 
      execsql { SELECT * FROM t1 } db$i
    }
    for {set i 0} {$i < 255} {incr i} { 
      set rc [vfs_shmlock db$i main shared lock 4 1]
      if {$rc != "SQLITE_OK"} { error $rc }
    }

    vfs_shmlock db255 main shared lock 4 1
  } {SQLITE_BUSY}

  do_test 2.1 { vfs_shmlock db255 main exclusive lock   4 1 } SQLITE_BUSY
  do_test 2.2 { vfs_shmlock db0   main shared    unlock 4 1 } SQLITE_OK
  do_test 2.3 { vfs_shmlock db255 main shared    lock   4 1 } SQLITE_OK
  do_test 2.4 { vfs_shmlock db255 main shared    unlock 4 1 } SQLITE_OK
  do_test 2.5 { vfs_shmlock db255 main exclusive lock   4 1 } SQLITE_BUSY

  do_test 2.6 {
    for {set i 1} {$i < 255} {incr i} { 
      set rc [vfs_shmlock db255 main exclusive lock 4 1]
      if {$rc != "SQLITE_BUSY"} { error $rc }
      set rc [vfs_shmlock db$i main shared unlock 4 1]
      if {$rc != "SQLITE_OK"} { error $rc }
    }

    vfs_shmlock db255 main exclusive lock 4 1
  } {SQLITE_OK}

  vfs_shmlock db255 main exclusive unlock 4 1

  for {set i 0} {$i < 256} {incr i} {
    db$i close
  }
}

sqlite3 db0 test.db
sqlite3 db1 test.db
do_test 3.1 { execsql { SELECT * FROM t1 } db0 } {1 2}
do_test 3.2 { execsql { SELECT * FROM t1 } db1 } {1 2}
if {$tcl_platform(os) eq "Windows NT"} {
  set isWindows 1
} else {
  set isWindows 0
}

set L(0) {n n n n n n n n}
set L(1) {n n n n n n n n}
proc random_lock_test {idx} {
  global L
  set iSlot [expr int(rand()*8)]
  if {[expr int(rand()*2)]} {
    # Unlock operation
    if {[lindex $L($idx) $iSlot]!="n"} {
      vfs_shmlock db$idx main [lindex $L($idx) $iSlot] unlock $iSlot 1
      lset L($idx) $iSlot n
    }
  } else {
    # Lock operation
    if {[lindex $L($idx) $iSlot]=="n"} {
      set locktype [lindex {e s} [expr int(rand()*2)]]
      set n 1
      if {$locktype=="e"} {
        for {set l $iSlot} {$l<8 && [lindex $L($idx) $l]=="n"} {incr l} {}
        set n [expr int(rand()*($l-$iSlot))+1]
        # The LockFile() and UnlockFile() apis on windows require that
        # every unlock correspond exactly to a prior lock.  Hence, we cannot
        # lock arbitrary ranges in this test on windows.
        if {$::isWindows} {set n 1}
        # puts "iSlot=$iSlot l=$l L=$L($idx)"
        # puts "$iSlot $n"
      }
      set res [vfs_shmlock db$idx main $locktype lock $iSlot $n]

      set bBusy 0
      for {set i $iSlot} {$i<($iSlot+$n)} {incr i} {
        set other [lindex $L([expr ($idx+1)%2]) $i]
        if {($other!="n" && $locktype=="e")||($other=="e" && $locktype=="s")} {
          if {$res != "SQLITE_BUSY"} { error "BUSY not detected" }
          set bBusy 1
          break
        } 
      }

      if {$bBusy==0} {
        if {$res != "SQLITE_OK"} { error "BUSY false-positive" }
        for {set i $iSlot} {$i<($iSlot+$n)} {incr i} {
          lset L($idx) $i $locktype
        }
      }
    }
  }
}

set nStep 100000
for {set i 0} {$i < $nStep} {incr i} {
  random_lock_test 0
  random_lock_test 1
}

db0 close
db1 close

finish_test
