TopologicalSort.cmake 5.56 KB
 Julien Malik committed Feb 18, 2015 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 ``````# Perform a reverse topological sort on the given LIST. # # topological_sort(my_list "MY_" "_EDGES") # # LIST is the name of a variable containing a list of elements to be # sorted in reverse topological order. Each element in the list has a # set of outgoing edges (for example, those other list elements that # it depends on). In the resulting reverse topological ordering # (written back into the variable named LIST), an element will come # later in the list than any of the elements that can be reached by # following its outgoing edges and the outgoing edges of any vertices # they target, recursively. Thus, if the edges represent dependencies # on build targets, for example, the reverse topological ordering is # the order in which one would build those targets. # # For each element E in this list, the edges for E are contained in # the variable named \${PREFIX}\${E}\${SUFFIX}. If no such variable # exists, then it is assumed that there are no edges. For example, if # my_list contains a, b, and c, one could provide a dependency graph # using the following variables: # # MY_A_EDGES b # MY_B_EDGES # MY_C_EDGES a b # # With the involcation of topological_sort shown above and these # variables, the resulting reverse topological ordering will be b, a, # c. ############################################################################## # Modified from Boost Utilities # # Copyright 2010 Kitware, Inc. ############################################################################## # Copyright 2007 Douglas Gregor # Copyright 2007 Troy Straszheim # # Distributed under the Boost Software License, Version 1.0. ############################################################################## # Boost Software License - Version 1.0 - August 17th, 2003 # # Permission is hereby granted, free of charge, to any person or organization # obtaining a copy of the software and accompanying documentation covered by # this license (the "Software") to use, reproduce, display, distribute, # execute, and transmit the Software, and to prepare derivative works of the # Software, and to permit third-parties to whom the Software is furnished to # do so, all subject to the following: # # The copyright notices in the Software and this entire statement, including # the above license grant, this restriction and the following disclaimer, # must be included in all copies of the Software, in whole or in part, and # all derivative works of the Software, unless such copies or derivative # works are solely in the form of machine-executable object code generated by # a source language processor. # # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, # FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT # SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE # FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE, # ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER # DEALINGS IN THE SOFTWARE. ############################################################################## function(topological_sort LIST PREFIX SUFFIX) # Clear the stack and output variable set(VERTICES "\${\${LIST}}") set(STACK) set(\${LIST}) # Loop over all of the vertices, starting the topological sort from # each one. foreach(VERTEX \${VERTICES}) # If we haven't already processed this vertex, start a depth-first # search from where. if (NOT FOUND_\${VERTEX}) # Push this vertex onto the stack with all of its outgoing edges string(REPLACE ";" " " NEW_ELEMENT "\${VERTEX};\${\${PREFIX}\${VERTEX}\${SUFFIX}}") list(APPEND STACK \${NEW_ELEMENT}) # We've now seen this vertex set(FOUND_\${VERTEX} TRUE) # While the depth-first search stack is not empty list(LENGTH STACK STACK_LENGTH) while(STACK_LENGTH GREATER 0) # Remove the vertex and its remaining out-edges from the top # of the stack list(GET STACK -1 OUT_EDGES) list(REMOVE_AT STACK -1) # Get the source vertex and the list of out-edges separate_arguments(OUT_EDGES) list(GET OUT_EDGES 0 SOURCE) list(REMOVE_AT OUT_EDGES 0) # While there are still out-edges remaining list(LENGTH OUT_EDGES OUT_DEGREE) while (OUT_DEGREE GREATER 0) # Pull off the first outgoing edge list(GET OUT_EDGES 0 TARGET) list(REMOVE_AT OUT_EDGES 0) if (NOT FOUND_\${TARGET}) # We have not seen the target before, so we will traverse # its outgoing edges before coming back to our # source. This is the key to the depth-first traversal. # We've now seen this vertex set(FOUND_\${TARGET} TRUE) # Push the remaining edges for the current vertex onto the # stack string(REPLACE ";" " " NEW_ELEMENT "\${SOURCE};\${OUT_EDGES}") list(APPEND STACK \${NEW_ELEMENT}) # Setup the new source and outgoing edges set(SOURCE \${TARGET}) set(OUT_EDGES \${\${PREFIX}\${SOURCE}\${SUFFIX}}) endif() list(LENGTH OUT_EDGES OUT_DEGREE) endwhile () # We have finished all of the outgoing edges for # SOURCE; add it to the resulting list. list(APPEND \${LIST} \${SOURCE}) # Check the length of the stack list(LENGTH STACK STACK_LENGTH) endwhile() endif () endforeach() set(\${LIST} \${\${LIST}} PARENT_SCOPE) endfunction()``````