diff options
Diffstat (limited to 'src/fix.cc')
| -rw-r--r-- | src/fix.cc | 295 |
1 files changed, 295 insertions, 0 deletions
diff --git a/src/fix.cc b/src/fix.cc new file mode 100644 index 000000000000..cb1990928469 --- /dev/null +++ b/src/fix.cc @@ -0,0 +1,295 @@ +#include <iostream> +#include <map> + +extern "C" { +#include <aterm2.h> +} + +#include "util.hh" + + +static string nixDescriptorDir; +static string nixSourcesDir; + + +typedef map<string, string> DescriptorMap; + + +void registerFile(string filename) +{ + int res = system(("nix regfile " + filename).c_str()); + if (WEXITSTATUS(res) != 0) + throw Error("cannot register " + filename + " with Nix"); +} + + +/* Download object referenced by the given URL into the sources + directory. Return the file name it was downloaded to. */ +string fetchURL(string url) +{ + unsigned int pos = url.rfind('/'); + if (pos == string::npos) throw Error("invalid url"); + string filename(url, pos + 1); + string fullname = nixSourcesDir + "/" + filename; + /* !!! quoting */ + string shellCmd = + "cd " + nixSourcesDir + " && wget --quiet -N \"" + url + "\""; + int res = system(shellCmd.c_str()); + if (WEXITSTATUS(res) != 0) + throw Error("cannot fetch " + url); + return fullname; +} + + +/* Return the directory part of the given path, i.e., everything + before the final `/'. */ +string dirOf(string s) +{ + unsigned int pos = s.rfind('/'); + if (pos == string::npos) throw Error("invalid file name"); + return string(s, 0, pos); +} + + +/* Term evaluation functions. */ + +string evaluateStr(ATerm e) +{ + char * s; + if (ATmatch(e, "<str>", &s)) + return s; + else throw Error("invalid string expression"); +} + + +ATerm evaluateBool(ATerm e) +{ + if (ATmatch(e, "True") || ATmatch(e, "False")) + return e; + else throw Error("invalid boolean expression"); +} + + +string evaluateFile(ATerm e, string dir) +{ + char * s; + ATerm t; + if (ATmatch(e, "<str>", &s)) { + checkHash(s); + return s; + } else if (ATmatch(e, "Url(<term>)", &t)) { + string url = evaluateStr(t); + string filename = fetchURL(url); + registerFile(filename); + return hashFile(filename); + } else if (ATmatch(e, "Local(<term>)", &t)) { + string filename = absPath(evaluateStr(t), dir); /* !!! */ + string cmd = "cp -p " + filename + " " + nixSourcesDir; + int res = system(cmd.c_str()); + if (WEXITSTATUS(res) != 0) + throw Error("cannot copy " + filename); + return hashFile(filename); + } else throw Error("invalid hash expression"); +} + + +ATerm evaluatePkg(ATerm e, DescriptorMap & done) +{ + char * s; + if (ATmatch(e, "<str>", &s)) { + checkHash(s); + return s; + } else throw Error("invalid hash expression"); +} + + +ATerm evaluate(ATerm e, string dir, DescriptorMap & done) +{ + ATerm t; + if (ATmatch(e, "Str(<term>)", &t)) + return ATmake("Str(<str>)", evaluateStr(t).c_str()); + else if (ATmatch(e, "Bool(<term>)", &t)) + return ATmake("Bool(<term>)", evaluateBool(t)); + else if (ATmatch(e, "File(<term>)", &t)) + return ATmake("File(<str>)", evaluateFile(t, dir).c_str()); + else if (ATmatch(e, "Pkg(<term>)", &t)) + return ATmake("Pkg(<term>)", evaluatePkg(t, done)); + else throw Error("invalid expression type"); +} + + +typedef map<string, ATerm> BindingsMap; + + +string getStringFromMap(BindingsMap & bindingsMap, + const string & name) +{ + ATerm e = bindingsMap[name]; + if (!e) throw Error("binding " + name + " is not set"); + char * s; + if (ATmatch(e, "Str(<str>)", &s)) + return s; + else + throw Error("binding " + name + " is not a string"); +} + + +/* Instantiate a Fix descriptors into a Nix descriptor, recursively + instantiating referenced descriptors as well. */ +string instantiateDescriptor(string filename, + DescriptorMap & done) +{ + /* Already done? */ + DescriptorMap::iterator isInMap = done.find(filename); + if (isInMap != done.end()) return isInMap->second; + + /* No. */ + string dir = dirOf(filename); + + /* Read the Fix descriptor as an ATerm. */ + ATerm inTerm = ATreadFromNamedFile(filename.c_str()); + if (!inTerm) throw Error("cannot read aterm " + filename); + + ATerm bindings; + if (!ATmatch(inTerm, "Descr(<term>)", &bindings)) + throw Error("invalid term in " + filename); + + /* Iterate over the bindings and evaluate them to normal form. */ + BindingsMap bindingsMap; /* the normal forms */ + + char * cname; + ATerm value; + while (ATmatch(bindings, "[Bind(<str>, <term>), <list>]", + &cname, &value, &bindings)) + { + string name(cname); + ATerm e = evaluate(value, dir, done); + bindingsMap[name] = e; + } + + /* Construct a descriptor identifier by concatenating the package + and release ids. */ + string pkgId = getStringFromMap(bindingsMap, "pkgId"); + string releaseId = getStringFromMap(bindingsMap, "releaseId"); + string id = pkgId + "-" + releaseId; + bindingsMap["id"] = ATmake("Str(<str>)", id.c_str()); + + /* Add a system name. */ + bindingsMap["system"] = ATmake("Str(<str>)", thisSystem.c_str()); + + /* Construct the resulting ATerm. Note that iterating over the + map yields the bindings in sorted order, which is exactly the + canonical form for Nix descriptors. */ + ATermList bindingsList = ATempty; + for (BindingsMap::iterator it = bindingsMap.begin(); + it != bindingsMap.end(); it++) + /* !!! O(n^2) */ + bindingsList = ATappend(bindingsList, + ATmake("Bind(<str>, <term>)", it->first.c_str(), it->second)); + ATerm outTerm = ATmake("Descr(<term>)", bindingsList); + + /* Write out the resulting ATerm. */ + string tmpFilename = nixDescriptorDir + "/tmp"; + if (!ATwriteToNamedTextFile(outTerm, tmpFilename.c_str())) + throw Error("cannot write aterm to " + tmpFilename); + + string outHash = hashFile(tmpFilename); + string outFilename = nixDescriptorDir + "/" + id + "-" + outHash + ".nix"; + if (rename(tmpFilename.c_str(), outFilename.c_str())) + throw Error("cannot rename " + tmpFilename + " to " + outFilename); + + cout << outFilename << endl; + + /* Register it with Nix. */ + registerFile(outFilename); + + done[filename] = outFilename; + return outFilename; +} + + +/* Instantiate a set of Fix descriptors into Nix descriptors. */ +void instantiateDescriptors(Strings filenames) +{ + DescriptorMap done; + + for (Strings::iterator it = filenames.begin(); + it != filenames.end(); it++) + { + string filename = absPath(*it); + instantiateDescriptor(filename, done); + } +} + + +/* Print help. */ +void printUsage() +{ + cerr << +"Usage: fix ... +"; +} + + +/* Parse the command-line arguments, call the right operation. */ +void run(Strings::iterator argCur, Strings::iterator argEnd) +{ + Strings extraArgs; + enum { cmdUnknown, cmdInstantiate } command = cmdUnknown; + + char * homeDir = getenv(nixHomeDirEnvVar.c_str()); + if (homeDir) nixHomeDir = homeDir; + + nixDescriptorDir = nixHomeDir + "/var/nix/descriptors"; + nixSourcesDir = nixHomeDir + "/var/nix/sources"; + + for ( ; argCur != argEnd; argCur++) { + string arg(*argCur); + if (arg == "-h" || arg == "--help") { + printUsage(); + return; + } if (arg == "--instantiate" || arg == "-i") { + command = cmdInstantiate; + } else if (arg[0] == '-') + throw UsageError("invalid option `" + arg + "'"); + else + extraArgs.push_back(arg); + } + + switch (command) { + + case cmdInstantiate: + instantiateDescriptors(extraArgs); + break; + + default: + throw UsageError("no operation specified"); + } +} + + +int main(int argc, char * * argv) +{ + ATerm bottomOfStack; + ATinit(argc, argv, &bottomOfStack); + + /* Put the arguments in a vector. */ + Strings args; + while (argc--) args.push_back(*argv++); + Strings::iterator argCur = args.begin(), argEnd = args.end(); + + argCur++; + + try { + run(argCur, argEnd); + } catch (UsageError & e) { + cerr << "error: " << e.what() << endl + << "Try `fix -h' for more information.\n"; + return 1; + } catch (exception & e) { + cerr << "error: " << e.what() << endl; + return 1; + } + + return 0; +} |