1 | package lib; |
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2 | |
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3 | use 5.005_64; |
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4 | use Config; |
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5 | |
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6 | my $archname = defined($Config{'archname'}) ? $Config{'archname'} : ''; |
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7 | my $ver = defined($Config{'version'}) ? $Config{'version'} : ''; |
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8 | my @inc_version_list = defined($Config{'inc_version_list'}) ? |
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9 | reverse split / /, $Config{'inc_version_list'} : (); |
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10 | |
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11 | our @ORIG_INC = @INC; # take a handy copy of 'original' value |
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12 | our $VERSION = '0.5564'; |
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13 | |
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14 | sub import { |
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15 | shift; |
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16 | |
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17 | my %names; |
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18 | foreach (reverse @_) { |
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19 | if ($_ eq '') { |
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20 | require Carp; |
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21 | Carp::carp("Empty compile time value given to use lib"); |
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22 | } |
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23 | if (-e && ! -d _) { |
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24 | require Carp; |
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25 | Carp::carp("Parameter to use lib must be directory, not file"); |
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26 | } |
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27 | unshift(@INC, $_); |
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28 | # Add any previous version directories we found at configure time |
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29 | foreach my $incver (@inc_version_list) |
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30 | { |
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31 | unshift(@INC, "$_/$incver") if -d "$_/$incver"; |
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32 | } |
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33 | # Put a corresponding archlib directory infront of $_ if it |
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34 | # looks like $_ has an archlib directory below it. |
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35 | unshift(@INC, "$_/$ver") if -d "$_/$ver"; |
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36 | unshift(@INC, "$_/$ver/$archname") if -d "$_/$ver/$archname"; |
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37 | } |
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38 | |
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39 | # remove trailing duplicates |
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40 | @INC = grep { ++$names{$_} == 1 } @INC; |
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41 | return; |
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42 | } |
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43 | |
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44 | |
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45 | sub unimport { |
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46 | shift; |
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47 | |
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48 | my %names; |
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49 | foreach (@_) { |
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50 | ++$names{$_}; |
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51 | ++$names{"$_/$archname"} if -d "$_/$archname/auto"; |
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52 | } |
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53 | |
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54 | # Remove ALL instances of each named directory. |
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55 | @INC = grep { !exists $names{$_} } @INC; |
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56 | return; |
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57 | } |
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58 | |
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59 | 1; |
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60 | __END__ |
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61 | |
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62 | =head1 NAME |
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63 | |
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64 | lib - manipulate @INC at compile time |
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65 | |
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66 | =head1 SYNOPSIS |
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67 | |
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68 | use lib LIST; |
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69 | |
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70 | no lib LIST; |
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71 | |
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72 | =head1 DESCRIPTION |
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73 | |
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74 | This is a small simple module which simplifies the manipulation of @INC |
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75 | at compile time. |
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76 | |
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77 | It is typically used to add extra directories to perl's search path so |
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78 | that later C<use> or C<require> statements will find modules which are |
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79 | not located on perl's default search path. |
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80 | |
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81 | =head2 Adding directories to @INC |
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82 | |
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83 | The parameters to C<use lib> are added to the start of the perl search |
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84 | path. Saying |
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85 | |
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86 | use lib LIST; |
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87 | |
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88 | is I<almost> the same as saying |
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89 | |
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90 | BEGIN { unshift(@INC, LIST) } |
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91 | |
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92 | For each directory in LIST (called $dir here) the lib module also |
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93 | checks to see if a directory called $dir/$archname/auto exists. |
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94 | If so the $dir/$archname directory is assumed to be a corresponding |
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95 | architecture specific directory and is added to @INC in front of $dir. |
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96 | |
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97 | To avoid memory leaks, all trailing duplicate entries in @INC are |
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98 | removed. |
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99 | |
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100 | =head2 Deleting directories from @INC |
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101 | |
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102 | You should normally only add directories to @INC. If you need to |
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103 | delete directories from @INC take care to only delete those which you |
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104 | added yourself or which you are certain are not needed by other modules |
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105 | in your script. Other modules may have added directories which they |
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106 | need for correct operation. |
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107 | |
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108 | The C<no lib> statement deletes all instances of each named directory |
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109 | from @INC. |
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110 | |
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111 | For each directory in LIST (called $dir here) the lib module also |
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112 | checks to see if a directory called $dir/$archname/auto exists. |
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113 | If so the $dir/$archname directory is assumed to be a corresponding |
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114 | architecture specific directory and is also deleted from @INC. |
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115 | |
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116 | =head2 Restoring original @INC |
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117 | |
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118 | When the lib module is first loaded it records the current value of @INC |
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119 | in an array C<@lib::ORIG_INC>. To restore @INC to that value you |
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120 | can say |
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121 | |
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122 | @INC = @lib::ORIG_INC; |
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123 | |
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124 | |
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125 | =head1 SEE ALSO |
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126 | |
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127 | FindBin - optional module which deals with paths relative to the source file. |
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128 | |
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129 | =head1 AUTHOR |
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130 | |
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131 | Tim Bunce, 2nd June 1995. |
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132 | |
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133 | =cut |
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