CMake/Source/cmIfCommand.h
Brad King f63304d982 if: Document that plain 'NOTFOUND' is a false constant
Previously we only mentioned the '-NOTFOUND' suffix.

Reported-by: Nils Gladitz <gladitz@sci-vis.de>
2012-10-05 15:14:29 -04:00

267 lines
10 KiB
C++

/*============================================================================
CMake - Cross Platform Makefile Generator
Copyright 2000-2009 Kitware, Inc., Insight Software Consortium
Distributed under the OSI-approved BSD License (the "License");
see accompanying file Copyright.txt for details.
This software is distributed WITHOUT ANY WARRANTY; without even the
implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the License for more information.
============================================================================*/
#ifndef cmIfCommand_h
#define cmIfCommand_h
#include "cmCommand.h"
#include "cmFunctionBlocker.h"
class cmIfFunctionBlocker : public cmFunctionBlocker
{
public:
cmIfFunctionBlocker() {
this->HasRun = false; this->ScopeDepth = 0; }
virtual ~cmIfFunctionBlocker() {}
virtual bool IsFunctionBlocked(const cmListFileFunction& lff,
cmMakefile &mf,
cmExecutionStatus &);
virtual bool ShouldRemove(const cmListFileFunction& lff,
cmMakefile &mf);
std::vector<cmListFileArgument> Args;
std::vector<cmListFileFunction> Functions;
bool IsBlocking;
bool HasRun;
unsigned int ScopeDepth;
};
/// Starts an if block
class cmIfCommand : public cmCommand
{
public:
/**
* This is a virtual constructor for the command.
*/
virtual cmCommand* Clone()
{
return new cmIfCommand;
}
/**
* This overrides the default InvokeInitialPass implementation.
* It records the arguments before expansion.
*/
virtual bool InvokeInitialPass(const std::vector<cmListFileArgument>& args,
cmExecutionStatus &);
/**
* This is called when the command is first encountered in
* the CMakeLists.txt file.
*/
virtual bool InitialPass(std::vector<std::string> const&,
cmExecutionStatus &) { return false;};
/**
* The name of the command as specified in CMakeList.txt.
*/
virtual const char* GetName() const { return "if";}
/**
* Succinct documentation.
*/
virtual const char* GetTerseDocumentation() const
{
return "Conditionally execute a group of commands.";
}
/**
* This determines if the command is invoked when in script mode.
*/
virtual bool IsScriptable() const { return true; }
/**
* More documentation.
*/
virtual const char* GetFullDocumentation() const
{
return
" if(expression)\n"
" # then section.\n"
" COMMAND1(ARGS ...)\n"
" COMMAND2(ARGS ...)\n"
" ...\n"
" elseif(expression2)\n"
" # elseif section.\n"
" COMMAND1(ARGS ...)\n"
" COMMAND2(ARGS ...)\n"
" ...\n"
" else(expression)\n"
" # else section.\n"
" COMMAND1(ARGS ...)\n"
" COMMAND2(ARGS ...)\n"
" ...\n"
" endif(expression)\n"
"Evaluates the given expression. If the result is true, the commands "
"in the THEN section are invoked. Otherwise, the commands in the "
"else section are invoked. The elseif and else sections are "
"optional. You may have multiple elseif clauses. Note that "
"the expression in the else and endif clause is optional. Long "
"expressions can be used and there is a traditional order of "
"precedence. "
"Parenthetical expressions are evaluated first followed by unary "
"operators such as EXISTS, COMMAND, and DEFINED. "
"Then any EQUAL, LESS, GREATER, STRLESS, STRGREATER, STREQUAL, MATCHES "
"will be evaluated. Then NOT operators and finally AND, OR operators "
"will be evaluated. Possible expressions are:\n"
" if(<constant>)\n"
"True if the constant is 1, ON, YES, TRUE, Y, or a non-zero number. "
"False if the constant is 0, OFF, NO, FALSE, N, IGNORE, NOTFOUND, '', "
"or ends in the suffix '-NOTFOUND'. "
"Named boolean constants are case-insensitive. "
"If the argument is not one of these constants, "
"it is treated as a variable:"
"\n"
" if(<variable>)\n"
"True if the variable is defined to a value that is not a false "
"constant. False otherwise. "
"(Note macro arguments are not variables.)"
"\n"
" if(NOT <expression>)\n"
"True if the expression is not true."
"\n"
" if(<expr1> AND <expr2>)\n"
"True if both expressions would be considered true individually."
"\n"
" if(<expr1> OR <expr2>)\n"
"True if either expression would be considered true individually."
"\n"
" if(COMMAND command-name)\n"
"True if the given name is a command, macro or function that can be "
"invoked.\n"
" if(POLICY policy-id)\n"
"True if the given name is an existing policy "
"(of the form CMP<NNNN>).\n"
" if(TARGET target-name)\n"
"True if the given name is an existing target, built or imported.\n"
" if(EXISTS file-name)\n"
" if(EXISTS directory-name)\n"
"True if the named file or directory exists. "
"Behavior is well-defined only for full paths.\n"
" if(file1 IS_NEWER_THAN file2)\n"
"True if file1 is newer than file2 or if one of the two files "
"doesn't exist. "
"Behavior is well-defined only for full paths. "
"If the file time stamps are exactly the same, an "
"IS_NEWER_THAN comparison returns true, so that any dependent "
"build operations will occur in the event of a tie. "
"This includes the case of passing the same file name for both "
"file1 and file2.\n"
" if(IS_DIRECTORY directory-name)\n"
"True if the given name is a directory. "
"Behavior is well-defined only for full paths.\n"
" if(IS_SYMLINK file-name)\n"
"True if the given name is a symbolic link. "
"Behavior is well-defined only for full paths.\n"
" if(IS_ABSOLUTE path)\n"
"True if the given path is an absolute path.\n"
" if(<variable|string> MATCHES regex)\n"
"True if the given string or variable's value matches the given "
"regular expression.\n"
" if(<variable|string> LESS <variable|string>)\n"
" if(<variable|string> GREATER <variable|string>)\n"
" if(<variable|string> EQUAL <variable|string>)\n"
"True if the given string or variable's value is a valid number and "
"the inequality or equality is true.\n"
" if(<variable|string> STRLESS <variable|string>)\n"
" if(<variable|string> STRGREATER <variable|string>)\n"
" if(<variable|string> STREQUAL <variable|string>)\n"
"True if the given string or variable's value is lexicographically "
"less (or greater, or equal) than the string or variable on the right.\n"
" if(<variable|string> VERSION_LESS <variable|string>)\n"
" if(<variable|string> VERSION_EQUAL <variable|string>)\n"
" if(<variable|string> VERSION_GREATER <variable|string>)\n"
"Component-wise integer version number comparison (version format is "
"major[.minor[.patch[.tweak]]]).\n"
" if(DEFINED <variable>)\n"
"True if the given variable is defined. It does not matter if the "
"variable is true or false just if it has been set.\n"
" if((expression) AND (expression OR (expression)))\n"
"The expressions inside the parenthesis are evaluated first and "
"then the remaining expression is evaluated as in the previous "
"examples. Where there are nested parenthesis the innermost are "
"evaluated as part of evaluating the expression "
"that contains them."
"\n"
"The if command was written very early in CMake's history, predating "
"the ${} variable evaluation syntax, and for convenience evaluates "
"variables named by its arguments as shown in the above signatures. "
"Note that normal variable evaluation with ${} applies before the "
"if command even receives the arguments. "
"Therefore code like\n"
" set(var1 OFF)\n"
" set(var2 \"var1\")\n"
" if(${var2})\n"
"appears to the if command as\n"
" if(var1)\n"
"and is evaluated according to the if(<variable>) case "
"documented above. "
"The result is OFF which is false. "
"However, if we remove the ${} from the example then the command sees\n"
" if(var2)\n"
"which is true because var2 is defined to \"var1\" which is not "
"a false constant."
"\n"
"Automatic evaluation applies in the other cases whenever the "
"above-documented signature accepts <variable|string>:\n"
"1) The left hand argument to MATCHES is first checked to see "
"if it is a defined variable, if so the variable's value is "
"used, otherwise the original value is used. \n"
"2) If the left hand argument to MATCHES is missing it returns "
"false without error \n"
"3) Both left and right hand arguments to LESS GREATER EQUAL "
"are independently tested to see if they are defined variables, "
"if so their defined values are used otherwise the original "
"value is used. \n"
"4) Both left and right hand arguments to STRLESS STREQUAL "
"STRGREATER are independently tested to see if they are defined "
"variables, if so their defined values are used otherwise the "
"original value is used. \n"
"5) Both left and right hand argumemnts to VERSION_LESS "
"VERSION_EQUAL VERSION_GREATER are independently tested to see "
"if they are defined variables, if so their defined values are "
"used otherwise the original value is used. \n"
"6) The right hand argument to NOT is tested to see if it is a "
"boolean constant, if so the value is used, otherwise it is "
"assumed to be a variable and it is dereferenced. \n"
"7) The left and right hand arguments to AND OR are "
"independently tested to see if they are boolean constants, if "
"so they are used as such, otherwise they are assumed to be "
"variables and are dereferenced. \n"
;
}
// this is a shared function for both If and Else to determine if the
// arguments were valid, and if so, was the response true. If there is
// an error, the errorString will be set.
static bool IsTrue(const std::vector<std::string> &args,
std::string &errorString, cmMakefile *mf,
cmake::MessageType &status);
// Get a definition from the makefile. If it doesn't exist,
// return the original string.
static const char* GetVariableOrString(const char* str,
const cmMakefile* mf);
cmTypeMacro(cmIfCommand, cmCommand);
};
#endif