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BLFS dependencies: better document the functions

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First the function used in pass1. Also some nit in the function itself
This commit is contained in:
Pierre Labastie 2021-12-18 15:28:47 +01:00
parent 7ae97740a8
commit dd9ca56bd2
1 changed files with 41 additions and 13 deletions
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54
BLFS/libs/func_dependencies
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@ -36,20 +36,46 @@
# originating from the parents. Third remove cycles and generate a #
# topological sort. #
# #
# TODO: document each pass
# Data layout: #
# TODO: needs also to document the .tree files, and the "f" qualifier
# #
# Pass 1: graph generation #
# ======================== #
# Data layout for pass 1 #
# ---------------------- #
# A node of the tree is represented by a text file <nodeName>.dep. Each edge #
# starting from this node is represented by a line in this file. We keep #
# those files in the same directory. We introduce a special node named root, #
# whose edges point to the list of nodes requested by the user. Each line #
# contains three fields: #
# - the weight of the edge #
# - the "before" (b) or "after" (a) qualifier #
# - the name of the destination of the edge #
# #
# TODO: The following is obsolete
# - the qualifier: "before" (b), "after" (a), or "first" (f) #
# - the name of the destination of the edge (without the ".dep" extension) #
# #
# Recursive function "generate_subgraph" #
# -------------------------------------- #
# This function treats a node of the graph that is not a leaf and that is #
# seen for the first time in the DFS. The dependencies of this node are #
# known, and stored in a .dep file. For each dependency in that file, there #
# are three cases: #
# - the weight of the edge leading to that dependency is higher than #
# requested. This dependency is discarded (some information printed) #
# - the weight of the edge is lower or equal to requested, but the node #
# has already been visited (the .dep file exists). Discard too (some #
# information printed) #
# - the weight of the edge is lower or equal to requested, and the node #
# has not been seen: then the dependencies of that node are generated, #
# and there are two cases: #
# - the node has no dependencies: just create an empty .dep file, so #
# that we know the node has been visited #
# - the node has dependencies: call generate_subgraph for that node #
# #
# This function takes four parameters: #
# - The node filename: this is the only one useful for the algorithm #
# - The depth: number of steps starting from root (for pretty print only) #
# - The weight of the edge leading to that node (for printing) #
# - The qualifier (for printing) #
# #
# TODO: document other passes #
# TODO: needs also to document the .tree files #
# TODO: The following is obsolete #
# Circular dependencies: #
# #
# In case we find a cirdular dependency, it has the form : #
@ -83,13 +109,14 @@ generate_subgraph() { #
followed for the DFS
$2 : weight of the edge leading to this node
$3 : depth (root is 1)
$4 : qualifier (a for after, b for before)
$4 : qualifier (a for after, b for before, f for first)
externals: vars: DEP_LEVEL contains 1 if we want to build the
tree only for required dependencies,
2 if we want also recommended ones,
3 if we want also optional ones, but only
for the requested packages,
4 if we want all the dependencies
(excluding external of course)
MAIL_SERVER contains the name of the MTA we want to use.
files: ../xsl/dependencies.xsl: stylesheet for creating the
.dep files
@ -120,8 +147,8 @@ case $weight in
3) priostring=optional ;;
esac
case $qualifier in
a) buildstring=runtime ;;
b) buildstring= ;;
a) buildstring=runtime ;;
b|f) buildstring= ;;
esac
dep_level=$DEP_LEVEL
if [ "$dep_level" = 3 ] && [ "$depth" -gt 2 ]; then dep_level=2; fi
@ -140,10 +167,11 @@ while read prio_of_dep build_of_dep id_of_dep; do
4) priostring=external ;;
esac
case $build_of_dep in
a) buildstring=runtime ;;
b) buildstring= ;;
a ) buildstring=runtime ;;
b|f) buildstring= ;;
esac
# Has this entry already been seen?
# TODO: no there is no special case!
# We have a special case here: if the entry has been seen at depth > 2
# and now depth=2 and DEP_LEVEL=3, optional deps have not been processed.
# If this is the case, just consider it has not been seen.