blob: 08fa03f18a3aa1c9cbbae8c3f74bbfa4b2794100 [file] [log] [blame]
/*
* Copyright 2019 Google LLC
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "src/utils/SkShaderUtils.h"
#include "include/core/SkString.h"
#include "include/private/SkSLString.h"
#include "include/private/base/SkTArray.h"
#include "src/sksl/SkSLProgramSettings.h"
#include <cstddef>
namespace SkShaderUtils {
class GLSLPrettyPrint {
public:
GLSLPrettyPrint() {}
std::string prettify(const std::string& string) {
fTabs = 0;
fFreshline = true;
// If a string breaks while in the middle 'parse until' we need to continue parsing on the
// next string
fInParseUntilNewline = false;
fInParseUntil = false;
int parensDepth = 0;
// setup pretty state
fIndex = 0;
fLength = string.length();
fInput = string.c_str();
while (fLength > fIndex) {
/* the heart and soul of our prettification algorithm. The rules should hopefully
* be self explanatory. For '#' and '//' tokens we parse until we reach a newline.
*
* For long style comments like this one, we search for the ending token. We also
* preserve whitespace in these comments WITH THE CAVEAT that we do the newlines
* ourselves. This allows us to remain in control of line numbers, and matching
* tabs Existing tabs in the input string are copied over too, but this will look
* funny
*
* '{' and '}' are handled in basically the same way. We add a newline if we aren't
* on a fresh line, dirty the line, then add a second newline, ie braces are always
* on their own lines indented properly. The one funkiness here is structs print
* with the semicolon on its own line. Its not a problem for a glsl compiler though
*
* '(' and ')' are basically ignored, except as a sign we need to ignore ';' ala
* in for loops.
*
* ';' means add a new line
*
* '\t' and '\n' are ignored in general parsing for backwards compatability with
* existing shader code and we also have a special case for handling whitespace
* at the beginning of fresh lines.
*
* Otherwise just add the new character to the pretty string, indenting if
* necessary.
*/
if (fInParseUntilNewline) {
this->parseUntilNewline();
} else if (fInParseUntil) {
this->parseUntil(fInParseUntilToken);
} else if (this->hasToken("#") || this->hasToken("//")) {
this->parseUntilNewline();
} else if (this->hasToken("/*")) {
this->parseUntil("*/");
} else if ('{' == fInput[fIndex]) {
this->newline();
this->appendChar('{');
fTabs++;
this->newline();
} else if ('}' == fInput[fIndex]) {
fTabs--;
this->newline();
this->appendChar('}');
this->newline();
} else if (this->hasToken(")")) {
parensDepth--;
} else if (this->hasToken("(")) {
parensDepth++;
} else if (!parensDepth && this->hasToken(";")) {
this->newline();
} else if ('\t' == fInput[fIndex] || '\n' == fInput[fIndex] ||
(fFreshline && ' ' == fInput[fIndex])) {
fIndex++;
} else {
this->appendChar(fInput[fIndex]);
}
}
return fPretty;
}
private:
void appendChar(char c) {
this->tabString();
SkSL::String::appendf(&fPretty, "%c", fInput[fIndex++]);
fFreshline = false;
}
// hasToken automatically consumes the next token, if it is a match, and then tabs
// if necessary, before inserting the token into the pretty string
bool hasToken(const char* token) {
size_t i = fIndex;
for (size_t j = 0; token[j] && fLength > i; i++, j++) {
if (token[j] != fInput[i]) {
return false;
}
}
this->tabString();
fIndex = i;
fPretty.append(token);
fFreshline = false;
return true;
}
void parseUntilNewline() {
while (fLength > fIndex) {
if ('\n' == fInput[fIndex]) {
fIndex++;
this->newline();
fInParseUntilNewline = false;
break;
}
SkSL::String::appendf(&fPretty, "%c", fInput[fIndex++]);
fInParseUntilNewline = true;
}
}
// this code assumes it is not actually searching for a newline. If you need to search for a
// newline, then use the function above. If you do search for a newline with this function
// it will consume the entire string and the output will certainly not be prettified
void parseUntil(const char* token) {
while (fLength > fIndex) {
// For embedded newlines, this code will make sure to embed the newline in the
// pretty string, increase the linecount, and tab out the next line to the appropriate
// place
if ('\n' == fInput[fIndex]) {
this->newline();
this->tabString();
fIndex++;
}
if (this->hasToken(token)) {
fInParseUntil = false;
break;
}
fFreshline = false;
SkSL::String::appendf(&fPretty, "%c", fInput[fIndex++]);
fInParseUntil = true;
fInParseUntilToken = token;
}
}
// We only tab if on a newline, otherwise consider the line tabbed
void tabString() {
if (fFreshline) {
for (int t = 0; t < fTabs; t++) {
fPretty.append("\t");
}
}
}
// newline is really a request to add a newline, if we are on a fresh line there is no reason
// to add another newline
void newline() {
if (!fFreshline) {
fFreshline = true;
fPretty.append("\n");
}
}
bool fFreshline;
int fTabs;
size_t fIndex, fLength;
const char* fInput;
std::string fPretty;
// Some helpers for parseUntil when we go over a string length
bool fInParseUntilNewline;
bool fInParseUntil;
const char* fInParseUntilToken;
};
std::string PrettyPrint(const std::string& string) {
GLSLPrettyPrint pp;
return pp.prettify(string);
}
void VisitLineByLine(const std::string& text,
const std::function<void(int lineNumber, const char* lineText)>& visitFn) {
SkTArray<SkString> lines;
SkStrSplit(text.c_str(), "\n", kStrict_SkStrSplitMode, &lines);
for (int i = 0; i < lines.size(); ++i) {
visitFn(i + 1, lines[i].c_str());
}
}
std::string BuildShaderErrorMessage(const char* shader, const char* errors) {
std::string abortText{"Shader compilation error\n"
"------------------------\n"};
VisitLineByLine(shader, [&](int lineNumber, const char* lineText) {
SkSL::String::appendf(&abortText, "%4i\t%s\n", lineNumber, lineText);
});
SkSL::String::appendf(&abortText, "Errors:\n%s", errors);
return abortText;
}
void PrintShaderBanner(SkSL::ProgramKind programKind) {
const char* typeName = "Unknown";
if (SkSL::ProgramConfig::IsVertex(programKind)) {
typeName = "Vertex";
} else if (SkSL::ProgramConfig::IsFragment(programKind)) {
typeName = "Fragment";
}
SkDebugf("---- %s shader ----------------------------------------------------\n", typeName);
}
} // namespace SkShaderUtils