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;;

;; Windows Pidgin NSIS installer plugin helper utilities

;;

;; Include in plugin installer scripts using:

;; !addincludedir "${PATH_TO_PIDGIN_SRC}\pidgin\win32\nsis"

;; !include "pidgin-plugin.nsh"

;;

!define PIDGIN_REG_KEY "SOFTWARE\pidgin"

!define PIDGIN_VERSION_OK 0

!define PIDGIN_VERSION_INCOMPATIBLE 1

!define PIDGIN_VERSION_UNDEFINED 2

; Extract the Pidgin Version from the registry

; This will set the Error flag if unable to determine the value

; Pop the value of the stack after calling this to get the value (unless Error Flag is set)

Function GetPidginVersion

Push $R0

; Read the pidgin version

ClearErrors

ReadRegStr $R0 HKLM ${PIDGIN_REG_KEY} "Version"

IfErrors +1 GetPidginVersion_found

; fall back to the HKCU registry key

ReadRegStr $R0 HKCU ${PIDGIN_REG_KEY} "Version"

IfErrors GetPidginVersion_done ; Keep the error flag set

GetPidginVersion_found:

Push $R0 ; Push the value onto the stack

Exch

GetPidginVersion_done:

; restore $R0

Pop $R0

FunctionEnd

; Check that the currently installed Pidgin version is compatible

; with the plugin version we are installing

; Push the Plugin's Pidgin Version onto the Stack before calling

; After calling, the top of the Stack will contain the result of the check:

; PIDGIN_VERSION_OK - If the installed Pidgin version is compatible w/ the version specified

; PIDGIN_VERSION_INCOMPATIBLE - If the installed Pidgin version isn't compatible w/ the version specified

; PIDGIN_VERSION_UNDEFINED - If the installed Pidgin version can't be determined

Function CheckPidginVersion

; Save the Variable values that we will use in the stack

Push $R4

Exch

Pop $R4 ; Get the plugin's Pidgin Version

Push $R0

Push $R1

Push $R2

; Read the pidgin version

Call GetPidginVersion

IfErrors checkPidginVersion_noPidginInstallFound

Pop $R0

;If they are exactly the same, we don't need to look at anything else

StrCmp $R0 $R4 checkPidginVersion_VersionOK

; Versions are in the form of X.Y.Z

; If X is different or plugin's Y > pidgin's Y, then we shouldn't install

;Check the Major Version

Push $R0

Push 0

Call GetVersionComponent

IfErrors checkPidginVersion_noPidginInstallFound ;We couldn't extract 'X' from the installed pidgin version

Pop $R2

Push $R4

Push 0

Call GetVersionComponent

IfErrors checkPidginVersion_BadVersion ; this isn't a valid version, so don't bother even checking

Pop $R1

;Check that both versions' X is the same

StrCmp $R1 $R2 +1 checkPidginVersion_BadVersion

;Check the Minor Version

Push $R0

Push 1

Call GetVersionComponent

IfErrors checkPidginVersion_noPidginInstallFound ;We couldn't extract 'Y' from the installed pidgin version

Pop $R2

Push $R4

Push 1

Call GetVersionComponent

IfErrors checkPidginVersion_BadVersion ; this isn't a valid version, so don't bother even checking

Pop $R1

;Check that plugin's Y <= pidgin's Y

IntCmp $R1 $R2 checkPidginVersion_VersionOK checkPidginVersion_VersionOK checkPidginVersion_BadVersion

checkPidginVersion_BadVersion:

Push ${PIDGIN_VERSION_INCOMPATIBLE}

goto checkPidginVersion_done

checkPidginVersion_noPidginInstallFound:

Push ${PIDGIN_VERSION_UNDEFINED}

goto checkPidginVersion_done

checkPidginVersion_VersionOK:

Push ${PIDGIN_VERSION_OK}

checkPidginVersion_done:

; Restore the Variables that we used

Exch

Pop $R2

Exch

Pop $R1

Exch

Pop $R0

Exch

Pop $R4

FunctionEnd

; Extract the part of a string prior to "." (or the whole string if there is no ".")

; If no "." was found, the ErrorFlag will be set

; Before this is called, Push ${VERSION_STRING} must be called, and then Push 0 for Major, 1 for Minor, etc

; Pop should be called after to retrieve the new value

Function GetVersionComponent

ClearErrors

; Save the Variable values that we will use in the stack

Push $1

Exch

Pop $1 ;The version component which we want to extract (0, 1, 2)

Exch

Push $0

Exch

Pop $0 ;The string from which to extract the version component

Push $2

Push $3

Push $4

Push $5

Push $6

Push $7

StrCpy $2 "0" ;Initialize our string index counter

StrCpy $7 "0" ;Index of last "."

StrCpy $3 "0" ;Initialize our version index counter

startGetVersionComponentLoop:

;avoid infinite loop (if we have gotten the whole initial string, exit the loop and set the error flag)

StrCmp $6 $0 GetVersionComponentSetErrorFlag

IntOp $2 $2 + 1

StrCpy $6 $0 $2 ;Update the infinite loop preventing string

;Determine the correct substring (only the current index component)

IntOp $5 $2 - $7

StrCpy $4 $0 $5 $7 ;Append the current character in $0 to $4

StrCpy $5 $0 1 $2 ;store the next character in $5

;if the next character is ".", $4 will contain the version component prior to "."

StrCmp $5 "." +1 startGetVersionComponentLoop

StrCmp $3 $1 doneGetVersionComponent ;If it is the version component we're looking for, stop

IntOp $3 $3 + 1 ;Increment the version index counter

IntOp $2 $2 + 1 ;Increment the version string index to "." (so it will be skipped)

StrCpy $7 $2 ;Keep track of the index of the last "."

StrCpy $6 $0 $2 ;Update the infinite loop preventing string

goto startGetVersionComponentLoop

GetVersionComponentSetErrorFlag:

SetErrors

doneGetVersionComponent:

; Restore the Variables that we used

Pop $7

Pop $6

Pop $5

Push $4 ;This is the value we're returning

Exch

Pop $4

Exch

Pop $3

Exch

Pop $2

Exch

Pop $0

Exch

Pop $1

FunctionEnd

pidgin/pidgin