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cmDepends: Refactor cmDepends::CheckDependencies method

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This patch changes the following issues in `cmDepends::CheckDependencies`:

- Use the `std::string` based `std::getline` interface to read lines from a
  file instead of using raw reads into raw buffers.
- To reduce the file system access, we load file times only once from
  `cmFileTimeCache` and keep them on the stack for later comparison.
- When a file is removed from the file system we remove it from the
  `cmFileTimeCache` as well.
This commit is contained in:
Sebastian Holtermann
2019-03-27 14:35:05 +01:00
parent 5f6c236481
commit 5a15c9e7cb
2 changed files with 69 additions and 76 deletions
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140
Source/cmDepends.cxx
View File

@@ -2,6 +2,7 @@
file Copyright.txt or https://cmake.org/licensing for details. */
#include "cmDepends.h"
#include "cmFileTime.h"
#include "cmFileTimeCache.h"
#include "cmGeneratedFileStream.h"
#include "cmLocalGenerator.h"
@@ -10,22 +11,15 @@
#include "cmsys/FStream.hxx"
#include <sstream>
#include <string.h>
#include <utility>
cmDepends::cmDepends(cmLocalGenerator* lg, std::string targetDir)
: LocalGenerator(lg)
, TargetDirectory(std::move(targetDir))
, Dependee(new char[MaxPath])
, Depender(new char[MaxPath])
{
}
cmDepends::~cmDepends()
{
delete[] this->Dependee;
delete[] this->Depender;
}
cmDepends::~cmDepends() = default;
bool cmDepends::Write(std::ostream& makeDepends, std::ostream& internalDepends)
{
@@ -76,9 +70,9 @@ bool cmDepends::Check(const std::string& makeFile,
// Clear all dependencies so they will be regenerated.
this->Clear(makeFile);
cmSystemTools::RemoveFile(internalFile);
this->FileTimeCache->Remove(internalFile);
okay = false;
}
return okay;
}
@@ -111,44 +105,58 @@ bool cmDepends::CheckDependencies(
std::istream& internalDepends, const std::string& internalDependsFileName,
std::map<std::string, DependencyVector>& validDeps)
{
// Read internal depends file time
cmFileTime internalDependsTime;
if (!this->FileTimeCache->Load(internalDependsFileName,
internalDependsTime)) {
return false;
}
// Parse dependencies from the stream. If any dependee is missing
// or newer than the depender then dependencies should be
// regenerated.
bool okay = true;
bool dependerExists = false;
std::string line;
line.reserve(1024);
std::string depender;
std::string dependee;
cmFileTime dependerTime;
cmFileTime dependeeTime;
DependencyVector* currentDependencies = nullptr;
while (internalDepends.getline(this->Dependee, this->MaxPath)) {
if (this->Dependee[0] == 0 || this->Dependee[0] == '#' ||
this->Dependee[0] == '\r') {
while (std::getline(internalDepends, line)) {
// Check if this an empty or a comment line
if (line.empty() || line.front() == '#') {
continue;
}
size_t len = internalDepends.gcount() - 1;
if (this->Dependee[len - 1] == '\r') {
len--;
this->Dependee[len] = 0;
// Drop carriage return character at the end
if (line.back() == '\r') {
line.pop_back();
if (line.empty()) {
continue;
}
}
if (this->Dependee[0] != ' ') {
memcpy(this->Depender, this->Dependee, len + 1);
// Calling FileExists() for the depender here saves in many cases 50%
// of the calls to FileExists() further down in the loop. E.g. for
// kdelibs/khtml this reduces the number of calls from 184k down to 92k,
// or the time for cmake -E cmake_depends from 0.3 s down to 0.21 s.
dependerExists = cmSystemTools::FileExists(this->Depender);
// Check if this a depender line
if (line.front() != ' ') {
depender = line;
dependerExists = this->FileTimeCache->Load(depender, dependerTime);
// If we erase validDeps[this->Depender] by overwriting it with an empty
// vector, we lose dependencies for dependers that have multiple
// entries. No need to initialize the entry, std::map will do so on first
// access.
currentDependencies = &validDeps[this->Depender];
currentDependencies = &validDeps[depender];
continue;
}
/*
// Parse the dependency line.
if(!this->ParseDependency(line.c_str()))
{
continue;
}
*/
// This is a dependee line
dependee = line.substr(1);
// Add dependee to depender's list
if (currentDependencies != nullptr) {
currentDependencies->push_back(dependee);
}
// Dependencies must be regenerated
// * if the dependee does not exist
@@ -156,13 +164,8 @@ bool cmDepends::CheckDependencies(
// * if the depender does not exist, but the dependee is newer than the
// depends file
bool regenerate = false;
const std::string dependee(this->Dependee + 1);
const std::string depender(this->Depender);
if (currentDependencies != nullptr) {
currentDependencies->push_back(dependee);
}
if (!cmSystemTools::FileExists(dependee)) {
bool dependeeExists = this->FileTimeCache->Load(dependee, dependeeTime);
if (!dependeeExists) {
// The dependee does not exist.
regenerate = true;
@@ -173,44 +176,38 @@ bool cmDepends::CheckDependencies(
<< depender << "\"." << std::endl;
cmSystemTools::Stdout(msg.str());
}
} else {
if (dependerExists) {
// The dependee and depender both exist. Compare file times.
int result = 0;
if ((!this->FileTimeCache->Compare(depender, dependee, &result) ||
result < 0)) {
// The depender is older than the dependee.
regenerate = true;
} else if (dependerExists) {
// The dependee and depender both exist. Compare file times.
if (dependerTime.Older(dependeeTime)) {
// The depender is older than the dependee.
regenerate = true;
// Print verbose output.
if (this->Verbose) {
std::ostringstream msg;
msg << "Dependee \"" << dependee << "\" is newer than depender \""
<< depender << "\"." << std::endl;
cmSystemTools::Stdout(msg.str());
}
// Print verbose output.
if (this->Verbose) {
std::ostringstream msg;
msg << "Dependee \"" << dependee << "\" is newer than depender \""
<< depender << "\"." << std::endl;
cmSystemTools::Stdout(msg.str());
}
} else {
// The dependee exists, but the depender doesn't. Regenerate if the
// internalDepends file is older than the dependee.
int result = 0;
if ((!this->FileTimeCache->Compare(internalDependsFileName, dependee,
&result) ||
result < 0)) {
// The depends-file is older than the dependee.
regenerate = true;
}
} else {
// The dependee exists, but the depender doesn't. Regenerate if the
// internalDepends file is older than the dependee.
if (internalDependsTime.Older(dependeeTime)) {
// The depends-file is older than the dependee.
regenerate = true;
// Print verbose output.
if (this->Verbose) {
std::ostringstream msg;
msg << "Dependee \"" << dependee
<< "\" is newer than depends file \""
<< internalDependsFileName << "\"." << std::endl;
cmSystemTools::Stdout(msg.str());
}
// Print verbose output.
if (this->Verbose) {
std::ostringstream msg;
msg << "Dependee \"" << dependee
<< "\" is newer than depends file \"" << internalDependsFileName
<< "\"." << std::endl;
cmSystemTools::Stdout(msg.str());
}
}
}
if (regenerate) {
// Dependencies must be regenerated.
okay = false;
@@ -218,13 +215,14 @@ bool cmDepends::CheckDependencies(
// Remove the information of this depender from the map, it needs
// to be rescanned
if (currentDependencies != nullptr) {
validDeps.erase(this->Depender);
validDeps.erase(depender);
currentDependencies = nullptr;
}
// Remove the depender to be sure it is rebuilt.
if (dependerExists) {
cmSystemTools::RemoveFile(depender);
this->FileTimeCache->Remove(depender);
dependerExists = false;
}
}

5
Source/cmDepends.h
View File

@@ -8,7 +8,6 @@
#include <iosfwd>
#include <map>
#include <set>
#include <stddef.h>
#include <string>
#include <vector>
@@ -105,10 +104,6 @@ protected:
// The full path to the target's build directory.
std::string TargetDirectory;
size_t MaxPath = 16384;
char* Dependee;
char* Depender;
// The include file search path.
std::vector<std::string> IncludePath;