utils: Add ProcessCallStack to collect stack traces for all threads in a process

- Also add a Printer class (print lines to logcat, fd, or strings)

Bug: 11324229
Change-Id: I78435ed49aa196a0efb45bf9b2d58b62c41737d3
diff --git a/include/utils/Printer.h b/include/utils/Printer.h
new file mode 100644
index 0000000..bb66287
--- /dev/null
+++ b/include/utils/Printer.h
@@ -0,0 +1,119 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_PRINTER_H
+#define ANDROID_PRINTER_H
+
+#include <android/log.h>
+
+namespace android {
+
+// Interface for printing to an arbitrary data stream
+class Printer {
+public:
+    // Print a new line specified by 'string'. \n is appended automatically.
+    // -- Assumes that the string has no new line in it.
+    virtual void printLine(const char* string = "") = 0;
+
+    // Print a new line specified by the format string. \n is appended automatically.
+    // -- Assumes that the resulting string has no new line in it.
+    virtual void printFormatLine(const char* format, ...) __attribute__((format (printf, 2, 3)));
+
+protected:
+    Printer();
+    virtual ~Printer();
+}; // class Printer
+
+// Print to logcat
+class LogPrinter : public Printer {
+public:
+    // Create a printer using the specified logcat and log priority
+    // - Unless ignoreBlankLines is false, print blank lines to logcat
+    // (Note that the default ALOG behavior is to ignore blank lines)
+    LogPrinter(const char* logtag,
+               android_LogPriority priority = ANDROID_LOG_DEBUG,
+               const char* prefix = 0,
+               bool ignoreBlankLines = false);
+
+    // Print the specified line to logcat. No \n at the end is necessary.
+    virtual void printLine(const char* string);
+
+private:
+    void printRaw(const char* string);
+
+    const char* mLogTag;
+    android_LogPriority mPriority;
+    const char* mPrefix;
+    bool mIgnoreBlankLines;
+}; // class LogPrinter
+
+// Print to a file descriptor
+class FdPrinter : public Printer {
+public:
+    // Create a printer using the specified file descriptor.
+    // - Each line will be prefixed with 'indent' number of blank spaces.
+    // - In addition, each line will be prefixed with the 'prefix' string.
+    FdPrinter(int fd, unsigned int indent = 0, const char* prefix = 0);
+
+    // Print the specified line to the file descriptor. \n is appended automatically.
+    virtual void printLine(const char* string);
+
+private:
+    enum {
+        MAX_FORMAT_STRING = 20,
+    };
+
+    int mFd;
+    unsigned int mIndent;
+    const char* mPrefix;
+    char mFormatString[MAX_FORMAT_STRING];
+}; // class FdPrinter
+
+class String8;
+
+// Print to a String8
+class String8Printer : public Printer {
+public:
+    // Create a printer using the specified String8 as the target.
+    // - In addition, each line will be prefixed with the 'prefix' string.
+    // - target's memory lifetime must be a superset of this String8Printer.
+    String8Printer(String8* target, const char* prefix = 0);
+
+    // Append the specified line to the String8. \n is appended automatically.
+    virtual void printLine(const char* string);
+
+private:
+    String8* mTarget;
+    const char* mPrefix;
+}; // class String8Printer
+
+// Print to an existing Printer by adding a prefix to each line
+class PrefixPrinter : public Printer {
+public:
+    // Create a printer using the specified printer as the target.
+    PrefixPrinter(Printer& printer, const char* prefix);
+
+    // Print the line (prefixed with prefix) using the printer.
+    virtual void printLine(const char* string);
+
+private:
+    Printer& mPrinter;
+    const char* mPrefix;
+};
+
+}; // namespace android
+
+#endif // ANDROID_PRINTER_H